Journal articles: 'Extracellular hydrolytic activities'

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Lee, Fu Haw, Suet Ying Wan, Hooi Ling Foo, Teck Chwen Loh, Rosfarizan Mohamad, Raha Abdul Rahim, and Zulkifli Idrus. "Comparative Study of Extracellular Proteolytic, Cellulolytic, and Hemicellulolytic Enzyme Activities and Biotransformation of Palm Kernel Cake Biomass by Lactic Acid Bacteria Isolated from Malaysian Foods." International Journal of Molecular Sciences 20, no. 20 (October 9, 2019): 4979. http://dx.doi.org/10.3390/ijms20204979.

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Biotransformation via solid state fermentation (SSF) mediated by microorganisms is a promising approach to produce useful products from agricultural biomass. Lactic acid bacteria (LAB) that are commonly found in fermented foods have been shown to exhibit extracellular proteolytic, β-glucosidase, β-mannosidase, and β-mannanase activities. Therefore, extracellular proteolytic, cellulolytic, and hemicellulolytic enzyme activities of seven Lactobacillus plantarum strains (a prominent species of LAB) isolated from Malaysian foods were compared in this study. The biotransformation of palm kernel cake (PKC) biomass mediated by selected L. plantarum strains was subsequently conducted. The results obtained in this study exhibited the studied L. plantarum strains produced versatile multi extracellular hydrolytic enzyme activities that were active from acidic to alkaline pH conditions. The highest total score of extracellular hydrolytic enzyme activities were recorded by L. plantarum RI11, L. plantarum RG11, and L. plantarum RG14. Therefore, they were selected for the subsequent biotransformation of PKC biomass via SSF. The hydrolytic enzyme activities of treated PKC extract were compared for each sampling interval. The scanning electron microscopy analyses revealed the formation of extracellular matrices around L. plantarum strains attached to the surface of PKC biomass during SSF, inferring that the investigated L. plantarum strains have the capability to grow on PKC biomass and perform synergistic secretions of various extracellular proteolytic, cellulolytic, and hemicellulolytic enzymes that were essential for the effective biodegradation of PKC. The substantial growth of selected L. plamtraum strains on PKC during SSF revealed the promising application of selected L. plantarum strains as a biotransformation agent for cellulosic biomass.

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Gandolfi, R., F. Marinelli, A. Lazzarini, and F. Molinari. "Cell-bound and extracellular carboxylesterases from Streptomyces: hydrolytic and synthetic activities." Journal of Applied Microbiology 89, no. 5 (November 2000): 870–75. http://dx.doi.org/10.1046/j.1365-2672.2000.01194.x.

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Geoffry, Kiptoo, and Rajeshwara N. Achur. "A novel halophilic extracellular lipase with both hydrolytic and synthetic activities." Biocatalysis and Agricultural Biotechnology 12 (October 2017): 125–30. http://dx.doi.org/10.1016/j.bcab.2017.09.012.

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Qiu, Quan-Sheng, and Xue-Feng Su. "The influence of extracellular-side Ca2+ on the activity of the plasma membrane H+-ATPase from wheat roots." Functional Plant Biology 25, no. 8 (1998): 923. http://dx.doi.org/10.1071/pp98036.

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Plasma membrane vesicles were purified from wheat roots by discontinuous sucrose gradient centrifugation and two-phase partitioning methods. The influence of extracellular-side Ca2+ on the activity of the plasma membrane H+ -ATPase from wheat roots was studied. The results showed that the ATP hydrolytic activities of the plasma membrane H+ -ATPase were inhibited by the cytoplasmic-side Ca2+. Within 0~200 µmol/L the ATPase activity decreased gradually with the increase in Ca2+ concentration; the ATPase activity was inhibited by 40% when Ca2+ concentration was 1000 µmol/L. However, the ATP hydrolytic activities were recovered by the presence of extracellular-side Ca2+. Results showed that the ATPase activities were increased with the increase in extracellular-side Ca2+; when the extracellular-side Ca2+ was 1000 µmol/L, the ATPase activity was recovered by 87.5%. Further studies found that the extracellular-side Ca2+ increased the DPH polarisation and decreased the MC540 fluorescence intensity, showing that membrane fluidity was decreased and membrane stacking was increased by the external Ca2+. The above results suggested that the plasma membrane H+ -ATPase could be regulated by the extracellular side Ca2+ through affecting the plasma membrane physical states.

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Ziervogel, K., A. D. Steen, and C. Arnosti. "Changes in the spectrum and rates of extracellular enzyme activities in seawater following aggregate formation." Biogeosciences Discussions 6, no. 6 (December 1, 2009): 11293–316. http://dx.doi.org/10.5194/bgd-6-11293-2009.

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Abstract. Marine snow aggregates are heavily colonized by heterotrophic microorganisms that express high levels of hydrolytic activities, making aggregates hotspots for carbon remineralization in the ocean. To assess how aggregate formation influences the ability of seawater microbial communities to access organic carbon, we compared hydrolysis rates of six polysaccharides in coastal seawater after aggregates had been formed (via incubation on a roller table) with hydrolysis rates in seawater from the same site that had not incubated on a roller table (referred to as whole seawater). Hydrolysis rates in the aggregates themselves were up to three orders of magnitude higher on a volume basis than in whole seawater. The enhancement of enzyme activity in aggregates relative to whole seawater differed by substrate, suggesting that the enhancement was under cellular control, rather than due to factors such as lysis or grazing. A comparison of hydrolysis rates in whole seawater with those in aggregate-free seawater, i.e. the fraction of water from the roller bottles that did not contain aggregates, demonstrated a nuanced microbial response to aggregate formation. Activities of laminarinase and xylanase enzymes in aggregate-free seawater were higher than in whole seawater, while activities of chondroitin, fucoidan, and arabinogalactan hydrolyzing enzymes were lower than in whole seawater. These data suggest that aggregate formation enhanced production of laminarinase and xylanase enzymes, and the enhancement also affected the surrounding seawater. Decreased activities of chondroitin, fucoidan, and arabinoglactan-hydrolyzing enzymes in aggregate-free seawater relative to whole seawater are likely due to shifts in enzyme production by the aggregate-associated community, coupled with the effects of enzyme degradation. Enhanced activities of laminarin- and xylan-hydrolyzing enzymes in aggregate-free seawater were due at least in part to cell-free enzymes. Measurements of enzyme lifetime using commercial enzymes suggest that hydrolytic lifetimes of cell-free enzymes may be sufficiently long to affect carbon remineralization in areas far from their site of production. Aggregate formation may be an important mechanism shaping the spectrum of enzymes active in the ocean, stimulating production of cell-free enzymes and leading to spatial and temporal decoupling of enzyme activity from the microorganisms that produced them.

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Ziervogel, K., A. D. Steen, and C. Arnosti. "Changes in the spectrum and rates of extracellular enzyme activities in seawater following aggregate formation." Biogeosciences 7, no. 3 (March 15, 2010): 1007–15. http://dx.doi.org/10.5194/bg-7-1007-2010.

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Abstract. Marine snow aggregates are heavily colonized by heterotrophic microorganisms that express high levels of hydrolytic activities, making aggregates hotspots for carbon remineralization in the ocean. To assess how aggregate formation influences the ability of seawater microbial communities to access organic carbon, we compared hydrolysis rates of six polysaccharides in coastal seawater after aggregates had been formed (via incubation on a roller table) with hydrolysis rates in seawater from the same site that had not incubated on a roller table (referred to as whole seawater). Hydrolysis rates in the aggregates themselves were up to three orders of magnitude higher on a volume basis than in whole seawater. The enhancement of enzyme activity in aggregates relative to whole seawater differed by substrate, suggesting that the enhancement was under cellular control, rather than due to factors such as lysis or grazing. A comparison of hydrolysis rates in whole seawater with those in aggregate-free seawater, i.e. the fraction of water from the roller bottles that did not contain aggregates, demonstrated a nuanced microbial response to aggregate formation. Activities of laminarinase and xylanase enzymes in aggregate-free seawater were higher than in whole seawater, while activities of chondroitin, fucoidan, and arabinogalactan hydrolyzing enzymes were lower than in whole seawater. These data suggest that aggregate formation enhanced production of laminarinase and xylanase enzymes, and the enhancement also affected the surrounding seawater. Decreased activities of chondroitin, fucoidan, and arabinoglactan-hydrolyzing enzymes in aggregate-free seawaters relative to whole seawater are likely due to shifts in enzyme production by the aggregate-associated community, coupled with the effects of enzyme degradation. Enhanced activities of laminarin- and xylan-hydrolyzing enzymes in aggregate-free seawater were due at least in part to cell-free enzymes. Measurements of enzyme lifetime using commercial enzymes suggest that hydrolytic cell-free enzymes may be active over timescales of days to weeks. Considering water residence times of up to 10 days in the investigation area (Apalachicola Bay), enzymes released from aggregates may be active over timescales long enough to affect carbon cycling in the Bay as well as in the adjacent Gulf of Mexico. Aggregate formation may thus be an important mechanism shaping the spectrum of enzymes active in the ocean, stimulating production of cell-free enzymes and leading to spatial and temporal decoupling of enzyme activity from the microorganisms that produced them.

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Tropeano, Mauro, Susana Vázquez, Silvia Coria, Adrián Turjanski, Daniel Cicero, Andrés Bercovich, and Walter Mac Cormack. "Extracellular hydrolytic enzyme production by proteolytic bacteria from the Antarctic." Polish Polar Research 34, no. 3 (June 1, 2013): 253–67. http://dx.doi.org/10.2478/popore-2013-0014.

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AbstractCold−adapted marine bacteria producing extracellular hydrolytic enzymes are important for their industrial application and play a key role in degradation of particulate organic matter in their natural environment. In this work, members of a previously−obtained protease−producing bacterial collection isolated from different marine sources from Potter Cove (King George Island, South Shetlands) were taxonomically identified and screened for their ability to produce other economically relevant enzymes. Eighty−eight proteolytic bacterial isolates were grouped into 25 phylotypes based on their Amplified Ribosomal DNA Restriction Analysis profiles. The sequencing of the 16S rRNA genes from representative isolates of the phylotypes showed that the predominant culturable protease−producing bacteria belonged to the class Gammaproteobacteria and were affiliated to the genera Pseudomonas, Shewanella, Colwellia, and Pseudoalteromonas, the latter being the predominant group (64% of isolates). In addition, members of the classes Actinobacteria, Bacilli and Flavobacteria were found. Among the 88 isolates screened we detected producers of amylases (21), pectinases (67), cellulases (53), CM−cellulases (68), xylanases (55) and agarases (57). More than 85% of the isolates showed at least one of the extracellular enzymatic activities tested, with some of them producing up to six extracellular enzymes. Our results confirmed that using selective conditions to isolate producers of one extracellular enzyme activity increases the probability of recovering bacteria that will also produce additional extracellular enzymes. This finding establishes a starting point for future programs oriented to the prospecting for biomolecules in Antarctica.

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Elshafie, Hazem S., and Ippolito Camele. "Rhizospheric Actinomycetes Revealed Antifungal and Plant-Growth-Promoting Activities under Controlled Environment." Plants 11, no. 14 (July 18, 2022): 1872. http://dx.doi.org/10.3390/plants11141872.

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Actinomycetes has large habitats and can be isolated from terrestrial soil, rhizospheres of plant roots, and marine sediments. Actinomycetes produce several bioactive secondary metabolites with antibacterial, antifungal, and antiviral properties. In this study, some Actinomycetes strains were isolated from the rhizosphere zone of four different plant species: rosemary, acacia, strawberry, and olive. The antagonistic activity of all isolates was screened in vitro against Escherichia coli and Bacillus megaterium. Isolates with the strongest bioactivity potential were selected and molecularly identified as Streptomyces sp., Streptomyces atratus, and Arthrobacter humicola. The growth-promoting activity of the selected Actinomycetes isolates was in vivo evaluated on tomato plants and for disease control against Sclerotinia sclerotiorum. The results demonstrated that all bacterized plants with the studied Actinomycetes isolates were able to promote the tomato seedlings’ growth, showing high values of ecophysiological parameters. In particular, the bacterized seedlings with Streptomyces sp. and A. humicola showed low disease incidence of S. sclerotiorum infection (0.3% and 0.2%, respectively), whereas those bacterized with S. atratus showed a moderate disease incidence (7.6%) compared with the positive control (36.8%). In addition, the ability of the studied Actinomycetes to produce extracellular hydrolytic enzymes was verified. The results showed that A. humicola was able to produce chitinase, glucanase, and protease, whereas Streptomyces sp. and S. atratus produced amylase and pectinase at high and moderate levels, respectively. This study highlights the value of the studied isolates in providing bioactive metabolites and extracellular hydrolytic enzymes, indicating their potential application as fungal-biocontrol agents.

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Păceşilă, Ioan. "Evaluation of Halobacterial Extracellular Hydrolytic Activities in Several Natural Saline and Hypersaline Lakes from Romania." British Biotechnology Journal 4, no. 5 (January 10, 2014): 541–50. http://dx.doi.org/10.9734/bbj/2014/10239.

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Satria, Heri, Yandri, Nurhasanah, Suripto Dwi Yuwono, and Dian Herasari. "Extracellular hydrolytic enzyme activities of indigenous actinomycetes on pretreated bagasse using choline acetate ionic liquid." Biocatalysis and Agricultural Biotechnology 24 (March 2020): 101503. http://dx.doi.org/10.1016/j.bcab.2020.101503.

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LUCACI, ANCA IOANA, SIMONA NEAGU, ROXANA COJOC, ROBERT RUGINESCU, IOAN ARDELEAN, and MĂDĂLIN ENACHE. "Benefits of understanding the enzymatic activities in saline Lake Letea in the Danube Delta." Romanian Biotechnological Letters 26, no. 2 (February 2, 2021): 2448–54. http://dx.doi.org/10.25083/rbl/26.2/2448.2454.

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The purpose of this paper was to isolate halophiles from Letea saline lake and to performed a screening for industrially relevant extracellular enzymes. The investigations were conducted from October 2016 until May 2018. After a random selection of colonies that grew on the medium culture, 82 isolates were investigated. Based on their salt requirements and tolerance, it was remarked the presence of isolates belonging to halotolerant and moderate halophilic bacteria. Morphological and biochemical tests were used to characterize them. The ability of the tested isolates to produce extracellular enzymes was evaluated on the culture medium with salinity varying between 0-4M and supplemented with a specific substrate. The highest hydrolytic activities were recorded for casein at 0M NaCl, 1M NaCl, 2M NaCl, and Tween 80 and inulin at 0M NaCl, 1M NaCl, 2M NaCl, and 3M NaCl.

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Liu, Zhihua, Ying Huang, Rongshu Zhang, Guiping Diao, Haijuan Fan, and Zhiying Wang. "Chitinase GenesLbCHI31andLbCHI32fromLimonium bicolorWere Successfully Expressed inEscherichia coliand Exhibit Recombinant Chitinase Activities." Scientific World Journal 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/648382.

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The two chitinase genes,LbCHI31andLbCHI32fromLimonium bicolor, were, respectively, expressed inEscherichia coliBL21 strain. The intracellular recombinant chitinases, inrCHI31 and inrCHI32, and the extracellular exrCHI31 and exrCHI32 could be produced intoE. coli. The exrCHI31 and exrCHI32 can be secreted into extracellular medium. The optimal reaction condition for inrCHI31 was 5 mmol/L of Mn2+at 40°C and pH 5.0 with an activity of 0.772 U usingAlternaria alternatacell wall as substrate. The optimal condition of inrCHI32 was 5 mmol/L of Ba2+at 45°C and pH 5.0 with an activity of 0.792 U usingValsa sordidacell wall as substrate. The optimal reaction condition of exrCHI31 was 5 mmol/L of Zn2+at 40°C and pH 5.0, and the activity was 0.921 U using theA. alternatacell wall as substrate. Simultaneously, the optimal condition of exrCHI32 was 5 mmol/L of K+at 45°C and pH 5.0, withV. sordidacell wall as the substrate, and the activity was 0.897 U. Furthermore, the activities of extracellular recombinant enzymes on fungal cell walls and compounds were generally higher than those of the intracellular recombinant enzymes. Recombinant exrCHI31 and exrCHI32 have better hydrolytic ability on cell walls of different fungi than synthetic chitins and obviously showed activity againstA. alternata.

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Gupta, Sonika, Parul Sharma, Kamal Dev, and Anuradha Sourirajan. "Halophilic Bacteria of Lunsu Produce an Array of Industrially Important Enzymes with Salt Tolerant Activity." Biochemistry Research International 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/9237418.

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The halophilic bacterial isolates SS1, SS2, SS3, SS5, and SS8 were characterized for production of industrially important enzymes like amylase, protease, lipase, and glutaminase. Halophilic bacterial isolates SS1 and SS3 exhibited salt dependent extracellular amylase and protease activities. Both the halophilic isolates SS1 and SS3 exhibited maximum amylase and protease activities in the presence of 1.5 and 1.0 M NaCl, respectively, with the optimum pH 8 and temperature 40°C. SS2 showed maximum extracellular protease and lipase activities in the presence of 0.75 M NaCl, at optimum pH of 7, and temperature 37°C. The glutaminase activity of SS3 increased with increase in concentration of NaCl up to 2.5 M. The optimum pH and temperature for L-glutaminase activity of SS3 was 8 and 40°C, respectively. The combined hydrolytic activities of these halophilic bacterial isolates can be used for bioconversion of organic materials to useful products.

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Moreau, Robert A., and Thomas S. Seibles. "Production of extracellular enzymes by germinating cysts of Phytophthora infestans." Canadian Journal of Botany 63, no. 10 (October 1, 1985): 1811–16. http://dx.doi.org/10.1139/b85-255.

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Cysts of Phytophthora infestans were prepared and allowed to germinate in water for 0 to 20 h. The activities of 11 different types of hydrolytic enzymes were detected in the extracellular germination medium. A time-course study revealed that most of the enzyme activities increased very little during germination. However, esterase activity increased 45-fold during germination. The rate of appearance of esterase activity closely paralleled the rate of germ tube growth. The intracellular levels of esterase activity were low throughout germination. These observations suggest that esterase is secreted during germination. Cysts also were allowed to germinate in the presence of various potential metabolic inhibitors and their effect on the appearance of esterase activity and on germ tube growth was measured. With each compound that inhibited the rate of germ tube growth, there was a nearly proportionate inhibition in the rate of appearance of extracellular esterase.

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Jindo, K., K. Matsumoto, C. García Izquierdo, T. Sonoki, and M. A. Sanchez-Monedero. "Methodological interference of biochar in the determination of extracellular enzyme activities in composting samples." Solid Earth 5, no. 2 (July 29, 2014): 713–19. http://dx.doi.org/10.5194/se-5-713-2014.

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Abstract. Biochar application has received increasing attention as a means to trap recalcitrant carbon and enhance soil fertility. Hydrolytic enzymatic assays, such as β-glucosidase and phosphatase activities, are used for the assessment of soil quality and composting process, which are based on use of p-nitrophenol (PNP) derivatives as substrate. However, sorption capacity of biochar can interfere with colorimetric determination of the hydrolysed PNP, either by the sorption of the substrate or the reaction product of hydrolysis into biochar surface. The aim of the present work is to study the biochar sorption capacity for PNP in biochar-blended composting mixtures in order to assess its impact on the estimation of the colorimetric-based enzymatic assays. A retention test was conducted by adding a solution of known amounts of PNP in universal buffer solution (pH = 5, 6.5 and 11, corresponding to the β-glucosidase, acid and alkaline phosphatase activity assays, respectively), in samples taken at the initial stage and after maturation stage from four different composting piles (two manure composting piles; PM: poultry manure, CM: cow manure and two other similar piles containing 10% of additional biochar (PM + B, CM + B)). The results show that biochar-blended composts (PM + B, CM + B) generally exhibited low enzymatic activities, compared to manure compost without biochar (PM, CM). In terms of the difference between the initial and maturation stage of composting process, the PNP retention in biochar was shown higher at maturation stage, caused most probably by an enlarged proportion of biochar inside compost mixture after the selective degradation of easily decomposable organic matter. TThe retention of PNP on biochar was influenced by pH dependency of sorption capacity of biochar and/or PNP solubility, since PNP was more efficiently retained by biochar at low pH values (5 and 6.5) than at high pH values (11).

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Jindo, K., K. Matsumoto, C. García Izquierdo, T. Sonoki, and M. A. Sanchez-Monedero. "Methodological interference of biochar in the determination of extracellular enzyme activities in composting samples." Solid Earth Discussions 6, no. 1 (March 26, 2014): 919–35. http://dx.doi.org/10.5194/sed-6-919-2014.

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Abstract. Biochar application has received increasing attention as a means to trap recalcitrant carbon and enhance soil fertility. Hydrolytic enzymatic assays, such as β-glucosidase and phosphatase activities, are used for the assessment of soil quality and composting process, which are based on use of p-nitrophenol (PNP) derivatives as substrate. However, sorption capacity of biochar can interfere colorimetric determination of the hydrolysed PNP, either by the sorption of the substrate or the reaction-product of hydrolysis into biochar surface. The aim of the present work is to study the biochar sorption capacity for PNP in biochar-blended composting mixtures in order to assess its impact on the estimation of the colorimetric-based enzymatic assays. A retention test was conducted by adding a solution of known amounts of PNP in universal buffer solution (pH = 5, 6.5 and 11, corresponding to the β-glucosidase, acid and alkaline phosphatase activity assays, respectively), in samples taken at the initial stage and after maturation stage from 4 different composting piles (two manure composting piles (PM: poultry manure, CM: cow manure) and two other similar piles containing 10% of additional biochar (PM + B, CM + B)). The results show that biochar blended composts (PM + B, CM + B) generally exhibited low enzymatic activities, compared to manure compost without biochar (PM, CM). In terms of the difference between the initial and maturation stage of composting process, the PNP retention in biochar was shown more clearly at maturation stage, caused by an enlarged proportion of biochar inside compost mixture after the selective degradation of easily decomposable organic matter. The retention of PNP was more pronounced at low pH (5 and 6.5) than at high pH (11), 3 reflecting on pH dependency of sorption 49 capacity of biochar and/or PNP 50 solubility.

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Balebona, M. Carmen, Manuel J. Andreu, M. Angeles Bordas, Irene Zorrilla, Miguel A. Moriñigo, and Juan J. Borrego. "Pathogenicity of Vibrio alginolyticusfor Cultured Gilt-Head Sea Bream (Sparus aurataL.)." Applied and Environmental Microbiology 64, no. 11 (November 1, 1998): 4269–75. http://dx.doi.org/10.1128/aem.64.11.4269-4275.1998.

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ABSTRACT The in vivo and in vitro pathogenic activities of whole cells and extracellular products of Vibrio alginolyticus for cultured gilt-head sea bream were evaluated. The 50% lethal doses ranged from 5.4 × 104 to 1.0 × 106 CFU/g of body weight. The strains examined had the ability to adhere to skin, gill, and intestinal mucus of sea bream and to cultured cells of a chinook salmon embryo cell line. In addition, the in vitro ability ofV. alginolyticus to adhere to mucus and skin cells of sea bream was demonstrated by scanning electron microscopy. The biological activities of extracellular products of V. alginolyticus were hydrolytic activities; the products were able to degrade sea bream mucus. V. alginolyticus was cytotoxic for fish cell lines and lethal for sea bream. Moreover, the extracellular products could degrade sea bream tissues. However, experiments performed with the bath immersion inoculation technique demonstrated that V. alginolyticus should be considered a pathogen for sea bream only when the mucus layer is removed and the skin is damaged.

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Alam, S., H. Shah, and N. Magan. "Water availability affects extracellular hydrolytic enzyme production by Aspergillus flavus and Aspergillus parasiticus." World Mycotoxin Journal 2, no. 3 (August 1, 2009): 313–22. http://dx.doi.org/10.3920/wmj2008.1108.

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The objectives of this study were to examine the effect of different water activities (aw; 0.99, 0.96 and 0.94) and time (up to 120 h) on quantitative and specific enzyme production during germination and initial growth of Aspergillus flavus and A. parasiticus strains at 25 °C. This is an important early indicator of potential for aflatoxin production under conducive conditions. Qualitative API ZYM generic enzyme strips were used to identify key hydrolytic enzymes produced. Subsequently, the temporal effects of aw on the total/specific activity of the key 4-5 hydrolytic enzymes were determined using 4-nitrophenyl substrates in a 96-well microtitre plate assay. The main enzymes produced by germinating conidia of A. flavus were esterase, lipase, acid phosphatase, β-glucosidase and N-acetyl-β-D-glucosaminidase, while for A. parasiticus these were alkaline phosphatase, lipase, acid phosphatase and β-fucosidase for both total (µmol 4-nitrophenol/min/g) and specific activity (nmol 4-nitrophenol/min/µg protein). There were significant increases in the specific activity of all these enzymes of germinating spores of A. flavus (0-120 h) except for β-glucosidase which was maximum at 72 h. The total/specific activities of the enzymes produced by A. flavus were maximum at 0.99 aw, with the exception of acid phosphatase and N-acetyl-β-D-glucosaminidase at 0.94 aw. For A. parasiticus, maximum total activity occurred at 0.99 aw for fucosidase activity, while specific activity was found to be higher at lower aw levels. These enzymes are important in early colonisation of food matrices by these species and single factors (aw, time) and two-way interactions were all statistically significant for the enzymes assayed for both species. These enzymes could be used as an early and rapid indicator of the activity of Aspergillus section flavi species and suggests that rapid infection may occur over a wide range of aw conditions.

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DELGADO, Jerónimo, Gloria MORO, Ana SABORIDO, and Alicia MEGÍAS. "T-tubule membranes from chicken skeletal muscle possess an enzymic cascade for degradation of extracellular ATP." Biochemical Journal 327, no. 3 (November 1, 1997): 899–907. http://dx.doi.org/10.1042/bj3270899.

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The chicken T-tubule Mg2+-ATPase is an integral membrane glycoprotein that presents properties different from those of other ATPases located in skeletal muscle cells and exhibits ATP-hydrolysing activity on the extracellular side of the transverse tubule (TT) membranes. In this study we demonstrate that TT vesicles purified from chicken skeletal muscle possess ecto-ADPase and ecto-5ʹ-nucleotidase activities that, along with ecto-ATPase, are able to sequentially degrade extracellular ATP to ADP, AMP and adenosine. Characterization studies of these TT ectonucleotidases revealed remarkable differences between ecto-ATPase and ecto-ADPase activities with respect to thermal stability, temperature dependence of the hydrolytic activity, effect of ionic strength, kinetic behaviour, divalent cation preference and responses to azide, N-ethylmaleimide, NaSCN, Triton X-100 and concanavalin A. Ecto-ATPase, but not ecto-ADPase, was inhibited by a polyclonal antibody against the chicken TT ecto-ATPase. On the basis of these results we propose that ATP and ADP hydrolysis are accomplished by two distinct enzymes and therefore the TT ecto-ATPase is not an apyrase. 5ʹ-Nucleotidase activity was inhibited by adenosine 5ʹ-[α,β-methylene]diphosphate and concanavalin A, followed simple Michaelis-Menten kinetics and was released from the membranes by treatment with phosphatidylinositol-specific phospholipase C, indicating that AMP hydrolysis in T-tubules is catalysed by a typical ecto-5ʹ-nucleotidase. Results obtained from electrophoresis experiments under native conditions suggest that ecto-ATPase, ecto-ADPase and 5ʹ-nucleotidase might be associated, forming functional complexes in the T-tubule membranes. The TT ectonucleotidases constitute an enzymic cascade for the degradation of extracellular ATP that might be involved in the regulation of purinergic signalling in the muscle fibre.

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Barik, Adyasa, Sudip Kumar Sen, Geetanjali Rajhans, and Sangeeta Raut. "Purification and Optimization of Extracellular Lipase from a Novel Strain Kocuria flava Y4." International Journal of Analytical Chemistry 2022 (February 5, 2022): 1–10. http://dx.doi.org/10.1155/2022/6403090.

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The exogenous lipolytic activities of Kocuria sp. have been recognized earlier but the genus further contains many more unexplored strains. In this study, the extracellular lipase activity of Kocuria flava Y4 (GenBank accession no. MT773277), isolated from Dioscorea villosa during our previous study, was regulated by different physicochemical parameters, such as pH, temperature, shaking speed, and incubation time. For efficient immobilization of the extracellular lipase, 4% sodium alginate, 50 mL of 25 nM CaCl2.2H2O solution, and 15 min. Hardening time of gel beads in calcium chloride was used. For the first time, K. flava Y4 lipase was purified using ammonium sulphate precipitation followed by dialysis and DEAE-Sepharose anion exchange chromatography with Sepharose-6B gel filtration chromatography, yielding ∼15-fold purified lipase with a final yield of 96 U/mL. The SDS-PAGE of purified lipase displayed a single strong band, indicating a monomeric protein of 45 kDa. At a temperature of 35°C and pH 8, the purified lipase showed maximum hydrolytic activity. Using p-nitrophenyl acetate (p-NPA) as the hydrolysis substrate, the values of Km and Vmax derived from the Lineweaver–Burk plot were 4.625 mM and 125 mol/min−1mg−1, respectively.

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Esteves, Ana Cristina, Márcia Saraiva, António Correia, and Artur Alves. "Botryosphaeriales fungi produce extracellular enzymes with biotechnological potential." Canadian Journal of Microbiology 60, no. 5 (May 2014): 332–42. http://dx.doi.org/10.1139/cjm-2014-0134.

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Phytopathogenic fungi are known for producing an arsenal of extracellular enzymes whose involvement in the infection mechanism has been suggested. However, these enzymes are largely unknown and their biotechnological potential also remains poorly understood. In this study, the production and thermostability of extracellular enzymes produced by phytopathogenic Botryosphaeriaceae was investigated. Hydrolytic and oxidative activities were detected and quantified at different temperatures. Most strains (70%; 37/53) were able to produce simultaneously cellulases, laccases, xylanases, pectinases, pectin lyases, amylases, lipases, and proteases. Surprisingly for mesophilic filamentous fungi, several enzymes proved to be thermostable: cellulases from Neofusicoccum mediterraneum CAA 001 and from Dothiorella prunicola CBS 124723, lipases from Diplodia pinea (CAA 015 and CBS 109726), and proteases from Melanops tulasnei CBS 116806 were more active at 70 °C than at any of the other temperatures tested. In addition, lipases produced by Diplodia pinea were found to be significantly more active than any other known lipase from Botryosphaeriales. The thermal activity profile and the wide array of activities secreted by these fungi make them optimal producers of biotechnologically relevant enzymes that may be applied in the food and the health industries (proteases), the pulp-and-paper and biofuel industries (cellulases), or even in the detergent industry (lipases, proteases, amylases, and cellulases).

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Hewins, Daniel B., Xiaozhu Chuan, Edward W. Bork, and Cameron N. Carlyle. "Measuring the effect of freezing on hydrolytic and oxidative extracellular enzyme activities associated with plant litter decomposition." Pedobiologia 59, no. 5-6 (November 2016): 253–56. http://dx.doi.org/10.1016/j.pedobi.2016.09.002.

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Jones, Susan E., and Maurice A. Lock. "Seasonal determinations of extracellular hydrolytic activities in heterotrophic and mixed heterotrophic/autotrophic biofilms from two contrasting rivers." Hydrobiologia 257, no. 1 (April 1993): 1–16. http://dx.doi.org/10.1007/bf00013991.

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Admassie, Mesele, Yitbarek Woldehawariat, and Tesfaye Alemu. "In Vitro Evaluation of Extracellular Enzyme Activity and Its Biocontrol Efficacy of Bacterial Isolates from Pepper Plants for the Management of Phytophthora capsici." BioMed Research International 2022 (September 26, 2022): 1–13. http://dx.doi.org/10.1155/2022/6778352.

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Phytophthora capsici is one of the most devastating fungal pathogens, causing severe diseases that lead to economic loss in the pepper industry. As a result of the infections, the chemical approach is becoming more popular. Biological control, on the other hand, is better suited to controlling fungal pathogens. The biological control approach significantly reduces the problems associated with chemical applications while restoring natural environmental balance. As a result, the overall findings indicate that certain bacterial isolates play a beneficial role in lytic enzyme production and biocontrol activities against P. capsici. Bacterial isolates obtained from the pepper plants were screened for lytic enzyme and anti-oomycete activity against Phytophthora capsici in Ethiopia. Sixty bacterial isolates were isolated and tested against Phytophthora capsici. From these bacterial isolates, different inhibition zones and hydrolytic enzyme production were detected. Biochemical tests using an automated machine (MALDI-TOF, VITEK 2 compact and 16S rRNA) revealed that three of them, AAUSR23, AAULE41, and AAULE51, showed a high inhibition zone and high production of hydrolytic enzymes and were identified as Enterobacter cloacae (AAUSR23), Pseudomonas fluorescens (AAULE41), and undetermined (AAULE51). The effects of diffusable metabolite isolate AAULE51 has a 66.7% inhibition zone against Phytophthora capsici, followed by AAULE41 and AAUSR23, which have 59.7% and 14.1% inhibition zones, respectively. These bacterial isolates showed high production of hydrolytic enzymes like protease, cellulase, chitinase, and lipase (5-34 diameter of inhibition zone). As a result, the overall findings show that selected bacterial isolates play a beneficial role in lytic enzyme production and for their biocontrol activities against P. capsici.

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Turner, Benjamin L. "Variation in pH Optima of Hydrolytic Enzyme Activities in Tropical Rain Forest Soils." Applied and Environmental Microbiology 76, no. 19 (August 13, 2010): 6485–93. http://dx.doi.org/10.1128/aem.00560-10.

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ABSTRACT Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly among enzymes and soils. Enzymes were grouped into three classes based on their pH optima: (i) enzymes with acidic pH optima that were consistent among soils (cellobiohydrolase, β-xylanase, and arylsulfatase), (ii) enzymes with acidic pH optima that varied systematically with soil pH, with the most acidic pH optima in the most acidic soils (α-glucosidase, β-glucosidase, and N-acetyl-β-glucosaminidase), and (iii) enzymes with an optimum pH in either the acid range or the alkaline range depending on soil pH (phosphomonoesterase and phosphodiesterase). The optimum pH values of phosphomonoesterase were consistent among soils, being 4 to 5 for acid phosphomonoesterase and 10 to 11 for alkaline phosphomonoesterase. In contrast, the optimum pH for phosphodiesterase activity varied systematically with soil pH, with the most acidic pH optima (3.0) in the most acidic soils and the most alkaline pH optima (pH 10) in near-neutral soils. Arylsulfatase activity had a very acidic optimum pH in all soils (pH ≤3.0) irrespective of soil pH. The differences in pH optima may be linked to the origins of the enzymes and/or the degree of stabilization on solid surfaces. The results have important implications for the interpretation of hydrolytic enzyme assays using fluorogenic substrates.

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Ravi, Bhargavi, Valentine Nkongndem Nkemka, Xiying Hao, Jay Yanke, Tim A. McAllister, Hung Lee, Chitraichamy Veluchamy, and Brandon H. Gilroyed. "Effect of Bioaugmentation with Anaerobic Fungi Isolated from Ruminants on the Hydrolysis of Corn Silage and Phragmites australis." Applied Sciences 11, no. 19 (September 30, 2021): 9123. http://dx.doi.org/10.3390/app11199123.

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Anaerobic fungi produce extracellular hydrolytic enzymes that facilitate degradation of cellulose and hemicellulose in ruminants. The purpose of this work was to study the impact of three different anaerobic fungal species (Anaeromyces mucronatus YE505, Neocallimastix frontalis 27, and Piromyces rhizinflatus YM600) on hydrolysis of two different lignocellulosic substrates, corn (Zea mays L.) silage and reed (Phragmites australis (Cav.) Trin. ex Steud.). Biomass from each plant species was incubated anaerobically for 11 days either in the presence of live fungal inoculum or with heat-inactivated (control) inoculum. Headspace gas composition, dry matter loss, soluble chemical oxygen demand, concentration of volatile fatty acids, and chemical composition were measured before and after hydrolysis. While some microbial activity was observed, inoculation with anaerobic fungi did not result in any significant difference in the degradation of either type of plant biomass tested, likely due to low fungal activity or survival under the experimental conditions tested. While the premise of utilizing the unique biological activities of anaerobic fungi for biotechnology applications remains promising, further research on optimizing culturing and process conditions is necessary.

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Baltar, Federico, Catherine Legrand, and Jarone Pinhassi. "Cell-free extracellular enzymatic activity is linked to seasonal temperature changes: a case study in the Baltic Sea." Biogeosciences 13, no. 9 (May 13, 2016): 2815–21. http://dx.doi.org/10.5194/bg-13-2815-2016.

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Abstract. Extracellular enzymatic activities (EEAs) are a crucial step in the degradation of organic matter. Dissolved (cell-free) extracellular enzymes in seawater can make up a significant contribution of the bulk EEA. However, the factors controlling the proportion of dissolved EEA in the marine environment remain unknown. Here we studied the seasonal changes in the proportion of dissolved relative to total EEA (of alkaline phosphatase (APase), β-glucosidase (BGase), and leucine aminopeptidase (LAPase)), in the Baltic Sea for 18 months. The proportion of dissolved EEA ranged between 37 and 100, 0 and 100, and 34 and 100 % for APase, BGase, and LAPase, respectively. A consistent seasonal pattern in the proportion of dissolved EEA was found among all the studied enzymes, with values up to 100 % during winter and < 40 % during summer. A significant negative relation was found between the proportion of dissolved EEA and temperature, indicating that temperature might be a critical factor controlling the proportion of dissolved relative to total EEA in marine environments. Our results suggest a strong decoupling of hydrolysis rates from microbial dynamics in cold waters. This implies that under cold conditions, cell-free enzymes can contribute to substrate availability at large distances from the producing cell, increasing the dissociation between the hydrolysis of organic compounds and the actual microbes producing the enzymes. This might also suggest a potential effect of global warming on the hydrolysis of organic matter via a reduction of the contribution of cell-free enzymes to the bulk hydrolytic activity.

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Skočaj, Matej, Andrej Gregori, Maja Grundner, Kristina Sepčić, and Mija Sežun. "Hydrolytic and oxidative enzyme production through cultivation of Pleurotus ostreatus on pulp and paper industry wastes." Holzforschung 72, no. 9 (September 25, 2018): 813–17. http://dx.doi.org/10.1515/hf-2017-0179.

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AbstractThe growth of oyster mushroom (Pleurotus ostreatus) on pulp and paper industry wastes was studied. Specifically, the question was investigated whether solid-state fermentation ofP. ostreatuson paper-mill deinking sludge and primary sludge substrates is appropriate for production of enzymes, relevant to the pulp and paper industry. Following fermentation, extracellular protein was extracted and the specific activities of four enzymes were determined, namely, the cellulase, xylanase, lipase and peroxidase. Furthermore, the effects of the pH of the extraction buffer on these enzyme activities were determined, along with the effects of the incubation time. The data show thatP. ostreatuscan grow on solid wastes from the pulp and paper industry, which could help to minimize the waste volume and to decrease the ecological impact. Furthermore, the solid wastes in focus are good substrates for the production of commercially interesting enzymes.

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Ortiz-Cortés, Lourdes Yaret, Lucía María Cristina Ventura-Canseco, Miguel Abud-Archila, Víctor Manuel Ruíz-Valdiviezo, Irving Oswaldo Velázquez-Ríos, and Peggy Elizabeth Alvarez-Gutiérrez. "Evaluation of temperature, pH and nutrient conditions in bacterial growth and extracellular hydrolytic activities of two Alicyclobacillus spp. strains." Archives of Microbiology 203, no. 7 (June 22, 2021): 4557–70. http://dx.doi.org/10.1007/s00203-021-02332-4.

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Rasmussen, Lauren, and Ola A. Olapade. "Influence of zinc on bacterial populations and their proteolytic enzyme activities in freshwater environments: a cross-site comparison." Canadian Journal of Microbiology 62, no. 4 (April 2016): 320–28. http://dx.doi.org/10.1139/cjm-2015-0638.

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Temporal responses of indigenous bacterial populations and proteolytic enzyme (i.e., aminopeptidase) activities in the bacterioplankton assemblages from 3 separate freshwater environments were examined after exposure to various zinc (Zn) concentrations under controlled microcosm conditions. Zn concentrations (ranging from 0 to 10 μmol/L) were added to water samples collected from the Kalamazoo River, Rice Creek, and Huron River and examined for bacterial abundance and aminopeptidase activities at various time intervals over a 48 h incubation period in the dark. The results showed that the Zn concentrations did not significantly influence total bacterial counts directly; however, aminopeptidase activities varied significantly to increasing zinc treatments over time. Also, analysis of variance and linear regression analyses revealed significant positive relationships between bacterial numbers and their hydrolytic enzyme activities, suggesting that both probably co-vary with increasing Zn concentrations in aquatic systems. The results from this study serve as additional evidence of the ecological role of Zn as an extracellular peptidase cofactor on the dynamics of bacterial assemblages in aquatic environments.

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Gomoiu, Ioana, Roxana Cojoc, Robert Ruginescu, Simona Neagu, Madalin Enache, Gabriel Maria, Maria Dumbrăvician, et al. "Brackish and Hypersaline Lakes as Potential Reservoir for Enzymes Involved in Decomposition of Organic Materials on Frescoes." Fermentation 8, no. 9 (September 16, 2022): 462. http://dx.doi.org/10.3390/fermentation8090462.

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This study highlights the decomposing role through the hydrolytic activities of fungi isolated from natural environments represented by brackish and hypersaline lakes in Romania. Novel strains belonging to the Penicillium, Aspergillus, and Emericellopsis genera were isolated and screened for the ability to produce extracellular hydrolytic enzymes, i.e., proteases, lipases, amylases, cellulases, xylanases, and pectinases. According to salt requirements, they were classified as moderate halophilic and halotolerant strains. Agar plate-based assays with Tween 80, slide cultures with organic deposits, and quantitative evaluation allowed the selection of Aspergillus sp. BSL 2-2, Penicillium sp. BSL 3-2, and Emericellopsis sp. MM2 as potentially good decomposers of organic matter not only in lakes but also on deposits covering the mural paintings. Experiments performed on painted experimental models revealed that only Penicillium sp. BSL 3-2 decomposed Paraloid B72, transparent dispersion of casein, beeswax, sunflower oil, and soot. Moreover, using microscopic, spectroscopic, and imaging methods, it was proved the efficiency of Penicillium sp. BSL 3-2 for decomposition of organic deposits artificially applied on frescoes fragments.

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Pandey, Nidhi, Munesh Kumar Gupta, and Ragini Tilak. "Extracellular hydrolytic enzyme activities of the different Candida spp. isolated from the blood of the Intensive Care Unit-admitted patients." Journal of Laboratory Physicians 10, no. 04 (October 2018): 392–96. http://dx.doi.org/10.4103/jlp.jlp_81_18.

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ABSTRACT BACKGROUND: Candida spp. secretes various extracellular hydrolytic enzymes. These enzymes are the important virulence factor for the pathogenesis of Candida. We assessed four different enzymatic activities of Candida isolates obtained from bloodstream infections. MATERIALS AND METHODS: We isolated 79 strains of different Candida species from the blood of the Intensive Care Unit-admitted patients. Species were identified by conventional methods including culture characteristic, germ tube, sugar assimilation, and Dalmau's culture technique. Phospholipase, proteinase, hemolysin, and esterase enzymatic activities were determined by the Plate method. RESULTS: Non albicans candida were the most common isolates from the blood of the ICU admitted patient with a predominance of Candida tropicalis. Hemolytic activity was the most prominent enzyme activity followed by the proteinase activity. Candida albicans (89.86%) was the major proteinase producer, while 95.8% of C. tropicalis produced hemolysin. No esterase activity was shown by the Candida glabrata and Candida krusei. CONCLUSION: No significant difference was observed between the two most common causative agents of candidemia: C. albicans and C. tropicalis.

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Kim, Hyun-Woo, Joo-Youn Nam, Seok-Tae Kang, Dong-Hoon Kim, Kyung-Won Jung, and Hang-Sik Shin. "Hydrolytic activities of extracellular enzymes in thermophilic and mesophilic anaerobic sequencing-batch reactors treating organic fractions of municipal solid wastes." Bioresource Technology 110 (April 2012): 130–34. http://dx.doi.org/10.1016/j.biortech.2012.01.146.

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34

Thompson, Grant L., Terrence H. Bell, and Jenny Kao-Kniffin. "Rethinking Invasion Impacts across Multiple Field Sites Using European Swallowwort (Vincetoxicum rossicum) as a Model Invader." Invasive Plant Science and Management 11, no. 3 (September 2018): 109–16. http://dx.doi.org/10.1017/inp.2018.22.

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AbstractEuropean swallowwort [Vincetoxicum rossicum (Kleopow) Barbarich] is found in the northeastern United States and southeastern Canada. It forms dense growth patterns that reduce plant and insect biodiversity, and lab assays show that it produces allelopathic compounds that affect microbial activity. Consequently, we hypothesized that V. rossicum alters soil microbiome composition and activity in invaded habitats, which may impact ecosystem properties and processes. We sampled soil from a similar time point within a growing season at each of five sites in New York State where V. rossicum was both present and absent. We measured bacterial and fungal microbiome composition, available soil nitrogen (N), soil respiration (CO2 flux), and soil extracellular enzyme activities. Microbial composition varied across field sites, but only fungal composition was affected by invasion. No significant differences were found between the invaded and uninvaded plots at any of the sites for available soil ammonium, nitrate, or respiration, though extractable N varied greatly between sites. Microbial hydrolytic extracellular enzyme activities suggest decreased protein degradation and increased oxidative enzyme activity with V. rossicum invasion, which is relevant to soil N and carbon cycling processes. Although V. rossicum impacted rhizosphere microbial composition and activity, it was not associated with large perturbations in ecosystem function when examined across multiple invasion sites during this short-term study.

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Tiquia, S. M. "Extracellular Hydrolytic Enzyme Activities of the Heterotrophic Microbial Communities of the Rouge River: An Approach to Evaluate Ecosystem Response to Urbanization." Microbial Ecology 62, no. 3 (May 25, 2011): 679–89. http://dx.doi.org/10.1007/s00248-011-9871-2.

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36

Renchinkhand, Gereltuya, Urgamal Magsar, Hyoung Churl Bae, Suk-Ho Choi, and Myoung Soo Nam. "Identification of β-Glucosidase Activity of Lentilactobacillus buchneri URN103L and Its Potential to Convert Ginsenoside Rb1 from Panax ginseng." Foods 11, no. 4 (February 12, 2022): 529. http://dx.doi.org/10.3390/foods11040529.

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Lentilactobacillus buchneri isolated from Korean fermented plant foods produces β-glucosidase, which can hydrolyze ginsenoside Rb1 from Panax ginseng to yield ginsenoside Rd. The aim of this study was to determine the mechanisms underlying the extracellular β-glucosidase activity obtained from Lentilactobacillus buchneri URN103L. Among the 17 types of lactic acid bacteria showing positive β-glucosidase activity in the esculin iron agar test, only URN103L was found to exhibit high hydrolytic activity on ginsenoside Rb1. The strain showed 99% homology with Lentilactobacillus buchneri NRRLB 30929, whereby it was named Lentilactobacillus buchneri URN103L. Supernatants of selected cultures with β-glucosidase activity were examined for hydrolysis of the major ginsenoside Rb1 at 40 °C, pH 5.0. Furthermore, the β-glucosidase activity of this strain showed a distinct ability to hydrolyze major ginsenoside Rb1 into minor ginsenosides Rd and Rg3. Lentilactobacillus buchneri URN103L showed higher leucine arylamidase, valine arylamidase, α-galactosidass, β–galactosidase, and β-glucosidase activities than any other strain. We conclude that β-glucosidase from Lentilactobacillus buchneri URN103L can effectively hydrolyze ginsenoside Rb1 into Rd and Rg3. The converted ginsenoside can be used in functional foods, yogurts, beverage products, cosmetics, and other health products.

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Neher, Deborah, Yong Bao, and Senyu Chen. "Effect of soil disturbance and biocides on nematode communities and extracellular enzyme activity in soybean cyst nematode suppressive soil." Nematology 13, no. 6 (2011): 687–99. http://dx.doi.org/10.1163/138855410x541230.

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AbstractSoybean cyst nematode (SCN), Heterodera glycines, remains a major yield-limiting pathogen of soybean. Natural suppression of SCN exists and becomes increasingly attractive; however, ecological mechanisms leading to the suppressive state are rarely studied. A glasshouse experiment was performed to determine the effects of soil disturbance and biocides on nematode community and extracellular enzyme activities in the SCN-suppressive soil collected in 2007 and 2008. Soil disturbance was simulated by passing soil through a sieve (aperture 5 mm) and compared with no-disturbance (non-sieve) treatment. Composition of microbial communities was manipulated by applying captan (fungicide), streptomycin (bactericide), captan plus streptomycin, or no biocide. SCN egg population density, proportion of second-stage juveniles (J2) parasitised by fungi, nematode communities in the soil, and plant weight in each pot were determined 70 days after planting soybean. In addition, the activities of six selected hydrolytic and oxidative extracellular enzymes representing cellulase, chitinase, serine protease, collagenase and peroxidase were measured. Soil disturbance resulted in an increase in SCN egg population density and reduction in the proportion of J2 parasitised by fungi. Biocide treatments increased SCN egg population density and the proportion of J2 parasitised by fungi at the end of experiment. Values of nematode community diversity index decreased and dominance and maturity indices increased in the disturbed soil compared with the no-disturbance treatment. Biocide treatments reduced maturity index values exclusively. With soil disturbance, the activity of extracellular enzyme L-proline aminopeptidase activity declined to less than half of that under no-disturbance in 2007. This experiment showed that both bacteria and fungi were potentially involved in the soil suppressiveness to SCN: soil disturbance and biocide application may reduce natural soil suppressiveness that was potentially associated with soil nematode community diversity and microbial enzyme activities.

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Gupta, Pratima, Kalpana Samant, and Avinash Sahu. "Isolation of Cellulose-Degrading Bacteria and Determination of Their Cellulolytic Potential." International Journal of Microbiology 2012 (2012): 1–5. http://dx.doi.org/10.1155/2012/578925.

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Eight isolates of cellulose-degrading bacteria (CDB) were isolated from four different invertebrates (termite, snail, caterpillar, and bookworm) by enriching the basal culture medium with filter paper as substrate for cellulose degradation. To indicate the cellulase activity of the organisms, diameter of clear zone around the colony and hydrolytic value on cellulose Congo Red agar media were measured. CDB 8 and CDB 10 exhibited the maximum zone of clearance around the colony with diameter of 45 and 50 mm and with the hydrolytic value of 9 and 9.8, respectively. The enzyme assays for two enzymes, filter paper cellulase (FPC), and cellulase (endoglucanase), were examined by methods recommended by the International Union of Pure and Applied Chemistry (IUPAC). The extracellular cellulase activities ranged from 0.012 to 0.196 IU/mL for FPC and 0.162 to 0.400 IU/mL for endoglucanase assay. All the cultures were also further tested for their capacity to degrade filter paper by gravimetric method. The maximum filter paper degradation percentage was estimated to be 65.7 for CDB 8. Selected bacterial isolates CDB 2, 7, 8, and 10 were co-cultured withSaccharomyces cerevisiaefor simultaneous saccharification and fermentation. Ethanol production was positively tested after five days of incubation with acidified potassium dichromate.

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Pitson, S. M., R. J. Seviour, B. M. McDougall, J. R. Woodward, and B. A. Stone. "Purification and characterization of three extracellular (1→3)-β-d-glucan glucohydrolases from the filamentous fungus Acremonium persicinum." Biochemical Journal 308, no. 3 (June 15, 1995): 733–41. http://dx.doi.org/10.1042/bj3080733.

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Three (1-->3)-beta-D-glucanases (GNs) were isolated from the culture filtrates of the filamentous fungus Acremonium persicinum and purified by (NH4)2SO4 precipitation followed by anion-exchange and gel-filtration chromatography. Homogeneity of the purified proteins was confirmed by SDS/PAGE, isoelectric focusing and N-terminal amino acid sequencing. All three GNs (GN I, II and III) are non-glycosylated, monomeric proteins with apparent molecular masses, estimated by SDS/PAGE, of 81, 85 and 89 kDa respectively. pI values for the three enzymes are 5.3, 5.1, and 4.4 respectively. The pH optimum for GN I is 6.5, and 5.0 for GN II and III. All three purified enzymes displayed stability over the pH range 4.5-10.0. Optimum activities for GN I, II and III were recorded at 65, 55 and 60 degrees C respectively, with both GN II and III having short-term stability up to 50 degrees C and GN I up to 55 degrees C. The purified GNs have high specificity for (1-->3)-beta-linkages and hydrolysed a range of (1-->3)-beta- and (1-->3)(1-->6)-beta-D-glucans, with laminarin from Laminaria digitata being the most rapidly hydrolysed substrate of those tested. K(m) values for GN I, II, and III against L. digitata laminarin were 0.1, 0.23 and 0.22 mg/ml respectively. D-Glucono-1,5-lactone does not inhibit any of the three GNs, some metals ions are mild inhibitors, and N-bromosuccinimide and KMnO4 are strong inhibitors. All three GNs acted in an exo-hydrolytic manner, determined by the release of alpha-glucose as the initial and major product of hydrolysis of (1-->3)-beta-D-glucans, and confirmed by viscometric analysis and the inability to cleave periodate-oxidized laminarin, and may be classified as (1-->3)-beta-D-glucan glucohydrolases (EC 3.2.1.58).

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Sugano, Junko, Ndegwa Maina, Janne Wallenius, and Kristiina Hildén. "Enhanced Lignocellulolytic Enzyme Activities on Hardwood and Softwood during Interspecific Interactions of White- and Brown-Rot Fungi." Journal of Fungi 7, no. 4 (March 31, 2021): 265. http://dx.doi.org/10.3390/jof7040265.

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Wood decomposition is a sophisticated process where various biocatalysts act simultaneously and synergistically on biopolymers to efficiently break down plant cell walls. In nature, this process depends on the activities of the wood-inhabiting fungal communities that co-exist and interact during wood decay. Wood-decaying fungal species have traditionally been classified as white-rot and brown-rot fungi, which differ in their decay mechanism and enzyme repertoire. To mimic the species interaction during wood decomposition, we have cultivated the white-rot fungus, Bjerkandera adusta, and two brown-rot fungi, Gloeophyllum sepiarium and Antrodia sinuosa, in single and co-cultivations on softwood and hardwood. We compared their extracellular hydrolytic carbohydrate-active and oxidative lignin-degrading enzyme activities and production profiles. The interaction of white-rot and brown-rot species showed enhanced (hemi)cellulase activities on birch and spruce-supplemented cultivations. Based on the enzyme activity profiles, the combination of B. adusta and G. sepiarium facilitated birch wood degradation, whereas B. adusta and A. sinuosa is a promising combination for efficient degradation of spruce wood, showing synergy in β-glucosidase (BGL) and α-galactosidase (AGL) activity. Synergistic BGL and AGL activity was also detected on birch during the interaction of brown-rot species. Our findings indicate that fungal interaction on different woody substrates have an impact on both simultaneous and sequential biocatalytic activities.

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Tajuddin, Natasha, Mohammed Rizman-Idid, Peter Convey, and Siti Aisyah Alias. "Thermal adaptation in a marine-derived tropical strain of Fusarium equiseti and polar strains of Pseudogymnoascus spp. under different nutrient sources." Botanica Marina 61, no. 1 (January 26, 2018): 9–20. http://dx.doi.org/10.1515/bot-2017-0049.

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AbstractWe documented relative growth rates (RGRs) and activities of extracellular hydrolytic enzymes (EHEs) of one marine-derived tropical strain ofFusarium equisetioriginally isolated from Malaysia and two polar strains ofPseudogymnoascusspp. from the Arctic and Antarctic under various temperatures and different nutrient conditions. RGRs and relative enzyme activities (RAs) of protease, amylase and cellulase were screened in seawater nutrient assay plates augmented with either skim milk, soluble starch or carboxymethylcellulose with trypan blue, respectively, across culture temperatures between 5°C and 40°C. Measures of RGR were fitted into third-degree polynomial and Brière-2 temperature-dependent models to estimate optimum temperatures for growth (Topt) and maximum growth rates (RGRmax), and were used to calculate temperature coefficients (Q10) and activation energies (Ea) for growth. All studied strains showed highest RGR and RA when grown using a skim milk nutrient assay.Toptfor growth was 25°C inF. equisetiand 20°C inPseudogymnoascusspp. OnlyF. equisetishowed cellulase activity. These data suggest a preference for protein-based substrates over plant-derived substrates for metabolism in these fungal strains. The tropicalF. equiseticould utilise higher levels of thermal energy for growth than the polar strains ofPseudogymnoascusspp., implying adaptation of these fungi to different bioclimatic regions.

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Blättel, V., M. Larisika, P. Pfeiffer, C. Nowak, A. Eich, J. Eckelt, and H. König. "β-1,3-Glucanase fromDelftia tsuruhatensisStrain MV01 and Its Potential Application in Vinification." Applied and Environmental Microbiology 77, no. 3 (December 17, 2010): 983–90. http://dx.doi.org/10.1128/aem.01943-10.

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ABSTRACTDuring vinification microbial activities can spoil wine quality. As the wine-related lactic acid bacteriumPediococcus parvulusis able to produce slimes consisting of a β-1,3-glucan, must and wine filtration can be difficult or impossible. In addition, the metabolic activities of several wild-type yeasts can also negatively affect wine quality. Therefore, there is a need for measures to degrade the exopolysaccharide fromPediococcus parvulusand to inhibit the growth of certain yeasts. We examined an extracellular β-1,3-glucanase fromDelftia tsuruhatensisstrain MV01 with regard to its ability to hydrolyze both polymers, the β-1,3-glucan fromPediococcusand that from yeast cell walls. The 29-kDa glycolytic enzyme was purified to homogeneity. It exhibited an optimal activity at 50°C and pH 4.0. The sequencing of the N terminus revealed significant similarities to β-1,3-glucanases from different bacteria. In addition, the investigations indicated that this hydrolytic enzyme is still active under wine-relevant parameters such as elevated ethanol, sulfite, and phenol concentrations as well as at low pH values. Therefore, the characterized enzyme seems to be a useful tool to prevent slime production and undesirable yeast growth during vinification.

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Ayuningrum, Diah, Aninditia Sabdaningsih, and Oktavianto Eko Jati. "The Potential of Phylogenetically Diverse Culturable Actinobacteria from Litopenaeus vannamei Pond Sediment as Extracellular Proteolytic and Lipolytic Enzyme Producers." Tropical Life Sciences Research 33, no. 3 (September 30, 2022): 165–92. http://dx.doi.org/10.21315/tlsr2022.33.3.10.

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Enzymes are catalysts that can increase the reaction time of a biochemical process. Hydrolytic enzymes have a pivotal role in degrading organic waste in both terrestrial and aquatic environments. The aims of this study were (1) to investigate the ability of actinobacteria isolated from Litopenaeus vannamei pond sediment to produce proteolytic and lipolytic enzymes, (2) to identify promising candidates using 16S rRNA gene amplification, and (3) to construct a phylogenetic tree based on the 16S rRNA genes. A skim milk agar medium was used in the preliminary experiment of the proteolytic assay, and a Tween 20/80 medium was used in the lipolytic assay. Fifteen and 20 (out of 40) actinobacterial isolates showed great potential for proteolytic and lipolytic activities, respectively. Furthermore, four actinobacteria isolates produced both enzyme types with proteolytic and lipolytic index scores of 1–6.5. The most promising candidates were SA 2.2 (IM8), SC 2.1 (IM6), SD 1.5 (IM6) and SE 1.1 (IM8). BLAST homology results showed a high similarity between the actinobacteria isolates and Streptomyces verucosisporus, S. mangrovicola, S. barkulensis and Nocardiopsis lucentensis, respectively. Therefore, actinobacteria from Litopenaeus vannamei pond sediment are high-potential proteolytic and lipolytic enzyme producers.

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GAHFIF, Ouahiba, Yasmina SOUAGUI, Zahra AZZOUZ, Sadrati NOUARI, Zahir AMGHAR Zahir AMGHAR, Nawel BOUCHERBA, Mouloud KECHA, Said BENALLAOUA, and Azzeddine Bettache. "Isolation and Screening of Fungal Culture Isolated From Algerian Soil for the Production of Cellulase and Xylanase." Journal of Drug Delivery and Therapeutics 10, no. 5-s (October 15, 2020): 108–13. http://dx.doi.org/10.22270/jddt.v10i5-s.4493.

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Lignocellulolytic enzymes constitute a very large group of extracellular proteins secreting by fungi who is ecologically involved in the degradation of a variety of complex materials, a property that is attributed to a battery of enzymes produced by these microorganisms like cellulases and xylanases who are of significant industrial value and relevance. Forty fungal isolated from rich soil in organic matter were screened for lignocellulolytic enzymes production, its organized on the basis of their hydrolytic potential of cellulose and xylan. The isolates strains presented enzymatic activity which was ranked as follows: cellulolytic (56%), xylanolytic (44%). Some selected strains that produce high levels of enzymes (cellulase, xylanase) grown in submerged fermentation (SmF) and were quantitatively evaluated. The fermentation experiments were carried out in shake flasks. The highest CMCase (5,10 IU/ml) and xylanase (98,25 IU/ml) activities were obtained from Trichoderma sp strain Mtr6 isolate. Keywords: Fungi, Trichoderma sp, lignocellulolytic enzymes, soil, screening, organic matter.

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Kadowaki, Marco, Mariana Godoy, Patricia Kumagai, Antonio Costa-Filho, Andrew Mort, Rolf Prade, and Igor Polikarpov. "Characterization of a New Glyoxal Oxidase from the Thermophilic Fungus Myceliophthora thermophila M77: Hydrogen Peroxide Production Retained in 5-Hydroxymethylfurfural Oxidation." Catalysts 8, no. 10 (October 19, 2018): 476. http://dx.doi.org/10.3390/catal8100476.

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Myceliophthora thermophyla is a thermophilic industrially relevant fungus that secretes an assortment of hydrolytic and oxidative enzymes for lignocellulose degradation. Among them is glyoxal oxidase (MtGLOx), an extracellular oxidoreductase that oxidizes several aldehydes and α-hydroxy carbonyl substrates coupled to the reduction of O2 to H2O2. This copper metalloprotein belongs to a class of enzymes called radical copper oxidases (CRO) and to the “auxiliary activities” subfamily AA5_1 that is based on the Carbohydrate-Active enZYmes (CAZy) database. Only a few members of this family have been characterized to date. Here, we report the recombinant production, characterization, and structure-function analysis of MtGLOx. Electron Paramagnetic Resonance (EPR) spectroscopy confirmed MtGLOx to be a radical-coupled copper complex and small angle X-ray scattering (SAXS) revealed an extended spatial arrangement of the catalytic and four N-terminal WSC domains. Furthermore, we demonstrate that methylglyoxal and 5-hydroxymethylfurfural (HMF), a fermentation inhibitor, are substrates for the enzyme.

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Duncan, Shona M., Ryuji Minasaki, Roberta L. Farrell, Joanne M. Thwaites, Benjamin W. Held, Brett E. Arenz, Joel A. Jurgens, and Robert A. Blanchette. "Screening fungi isolated from historicDiscoveryHut on Ross Island, Antarctica for cellulose degradation." Antarctic Science 20, no. 5 (May 16, 2008): 463–70. http://dx.doi.org/10.1017/s0954102008001314.

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AbstractTo survive in Antarctica, early explorers of Antarctica's Heroic Age erected wooden buildings and brought in large quantities of supplies. The introduction of wood and other organic materials may have provided new nutrient sources for fungi that were indigenous to Antarctica or were brought in with the materials. From 30 samples taken fromDiscoveryHut, 156 filamentous fungi were isolated on selective media. Of these, 108 were screened for hydrolytic activity on carboxymethyl cellulose, of which 29 demonstrated activities. Endo-1, 4-β-glucanase activity was confirmed in the extracellular supernatant from seven isolates when grown at 4°C, and also when they were grown at 15°C.Cladosporium oxysporumandGeomycessp. were shown to grow on a variety of synthetic cellulose substrates and to use cellulose as a nutrient source at temperate and cold temperatures. The research findings from the present study demonstrate that Antarctic filamentous fungi isolated from a variety of substrates (wood, straw, and food stuffs) are capable of cellulose degradation and can grow well at low temperatures.

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Kobayashi, Donald Y., Ralph M. Reedy, Jeffrey D. Palumbo, Jun-Ma Zhou, and Gary Y. Yuen. "A clp Gene Homologue Belonging to the Crp Gene Family Globally Regulates Lytic Enzyme Production, Antimicrobial Activity, and Biological Control Activity Expressed by Lysobacter enzymogenes Strain C3." Applied and Environmental Microbiology 71, no. 1 (January 2005): 261–69. http://dx.doi.org/10.1128/aem.71.1.261-269.2005.

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ABSTRACT Lysobacter enzymogenes strain C3, a biological control agent for plant diseases, produces multiple extracellular hydrolytic enzymes and displays antimicrobial activity against various fungal and oomycetous species. However, little is known about the regulation of these enzymes or their roles in antimicrobial activity and biocontrol. A study was undertaken to identify mutants of strain C3 affected in extracellular enzyme production and to evaluate their biocontrol efficacy. A single mini-Tn5-lacZ 1 -cat transposon mutant of L. enzymogenes strain C3 that was globally affected in a variety of phenotypes was isolated. In this mutant, 5E4, the activities of several extracellular lytic enzymes, gliding motility, and in vitro antimicrobial activity were reduced. Characterization of 5E4 indicated that the transposon inserted in a clp gene homologue belonging to the Crp gene family of regulators. Immediately downstream was a second open reading frame similar to that encoding acetyltransferases belonging to the Gcn5-related N-acetyltransferase superfamily, which reverse transcription-PCR confirmed was cotranscribed with clp. Chromosomal deletion mutants with mutations in clp and between clp and the acetyltransferase gene verified the 5E4 mutant phenotype. The clp gene was chromosomally inserted in mutant 5E4, resulting in complemented strain P1. All mutant phenotypes were restored in P1, although the gliding motility was observed to be excessive compared with that of the wild-type strain. clp mutant strains were significantly affected in biological control of pythium damping-off of sugar beet and bipolaris leaf spot of tall fescue, which was partially or fully restored in the complemented strain P1. These results indicate that clp is a global regulatory gene that controls biocontrol traits expressed by L. enzymogenes C3.

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Hassan, Waseem, Yu’e Li, Tahseen Saba, Jianshuang Wu, Safdar Bashir, Saqib Bashir, Mansour K. Gatasheh, Zeng-Hui Diao, and Zhongbing Chen. "Temperature responsiveness of soil carbon fractions, microbes, extracellular enzymes and CO₂ emission: mitigating role of texture." PeerJ 10 (May 5, 2022): e13151. http://dx.doi.org/10.7717/peerj.13151.

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The interaction of warming and soil texture on responsiveness of the key soil processes i.e. organic carbon (C) fractions, soil microbes, extracellular enzymes and CO2 emissions remains largely unknown. Global warming raises the relevant question of how different soil processes will respond in near future, and what will be the likely regulatory role of texture? To bridge this gap, this work applied the laboratory incubation method to investigate the effects of temperature changes (10–50 °C) on dynamics of labile, recalcitrant and stable C fractions, soil microbes, microbial biomass, activities of extracellular enzymes and CO2 emissions in sandy and clayey textured soils. The role of texture (sandy and clayey) in the mitigation of temperature effect was also investigated. The results revealed that the temperature sensitivity of C fractions and extracellular enzymes was in the order recalcitrant C fractions > stable C fractions > labile C fractions and oxidative enzymes > hydrolytic enzymes. While temperature sensitivity of soil microbes and biomass was in the order bacteria > actinomycetes > fungi ≈ microbial biomass C (MBC) > microbial biomass N (MBN) > microbial biomass N (MBP). Conversely, the temperature effect and sensitivity of all key soil processes including CO2 emissions were significantly (P < 0.05) higher in sandy than clayey textured soil. Results confirmed that under the scenario of global warming and climate change, soils which are sandy in nature are more susceptible to temperature increase and prone to become the CO2-C sources. It was revealed that clayey texture played an important role in mitigating and easing off the undue temperature influence, hence, the sensitivity of key soil processes.

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Tarazona, Eva, María A. Ruvira, Teresa Lucena, M. Carmen Macián, David R. Arahal, and María J. Pujalte. "Vibrio renipiscarius sp. nov., isolated from cultured gilthead sea bream (Sparus aurata)." International Journal of Systematic and Evolutionary Microbiology 65, Pt_6 (June 1, 2015): 1941–45. http://dx.doi.org/10.1099/ijs.0.000200.

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Two strains of Gram-negative, facultatively anaerobic, slightly halophilic bacteria, isolated from healthy gilthead sea bream (Sparus aurata) cultured in Spanish Mediterranean fish farms, were different from their closest relatives, Vibrio scophthalmi and V. ichthyoenteri, by phenotypic, phylogenetic and genomic standards. The strains were negative for decarboxylase tests and lacked extracellular hydrolytic activities, but were able to ferment d-mannitol, sucrose, cellobiose and d-gluconate, among other carbohydrates. The major cellular fatty acids were C16: 1 and C16: 0, in agreement with other species of the genus Vibrio. Their 16S rRNA gene sequences were 98.4 and 97.2 % similar to those of the type strains of V. scophthalmi and V. ichthyoenteri, and the similarities using other housekeeping genes (ftsZ, rpoD, recA, mreB and gyrB) and indices of genomic resemblance (average nucleotide identity and estimated DNA–DNA hybridization) between the isolates and those type strains were clearly below intraspecific levels, supporting the recognition of the strains as members of a separate novel species. Thus, we propose the name Vibrio renipiscarius sp. nov., with DCR 1-4-2T ( = CECT 8603T = KCTC 42287T) as the type strain.

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Ellwood, NTW, MM Pasella, C. Totti, and S. Accoroni. "Growth and phosphatase activities of Ostreopsis cf. ovata biofilms supplied with diverse dissolved organic phosphorus (DOP) compounds." Aquatic Microbial Ecology 85 (November 5, 2020): 155–66. http://dx.doi.org/10.3354/ame01946.

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It is becoming increasingly evident that the use of organic nutrients is widespread among many aquatic phototrophic organisms. Simultaneously, incidents of eutrophication of coastal waters are becoming more common due to rises in organic nutrient loads deriving from anthropogenic activities and natural terrestrial processes. In the northern Adriatic Sea, blooms of the toxic dinoflagellate Ostreopsis cf. ovata are reported as a frequent phenomenon linked to particular environmental conditions, including increased organic nutrient loads. Ostreopsis blooms typically produce a mucilaginous biofilm that can cover all benthic substrata. In order to clarify the role of dissolved organic phosphorus (DOP) in the onset and maintenance of an O. cf. ovata bloom, we investigated the growth rates in the presence of a range of phosphomonoesters (PMEs) (D-fructose 1,6-disphosphate, β-glycerophosphate, α-D-glucose 1-phosphate, guanosine 5’-monophosphate and phytic acid) and phosphodiesters (PDEs) (DNA and RNA). Levels of both phosphomonoesterase (PMEase) and phosphodiesterase (PDEase) activities were assessed in the O. cf. ovata biofilms. The results showed that O. cf. ovata growth is not inhibited in media containing a wide range of DOP and diverse ratios of PME:PDE compared to those containing inorganic phosphorus. Much of the hydrolytic activity was associated with bacteria and with extracellular polymeric substances (EPSs). Our findings suggest that the success of O. cf. ovata stems from the collective participation of all components of the biofilm (O. cf. ovata, EPSs and bacteria) that allows it to thrive in phosphorus-limited environments, but where the main source of phosphorus is organic.

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Journal articles on the topic 'Extracellular hydrolytic activities'

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