Academic literature on the topic 'Decolourization assay'

Sudarshanapowder (SP) is one of the most effective Ayurveda powder preparations for paediatric febrile conditions. The objective of the present study was to evaluate thein vitroandin vivoantioxidant potentials of SP. Thein vitroantioxidant effects were evaluated using ABTS radical cation decolourization assay where the TROLOX equivalent antioxidant capacity (TEAC) was determined. Thein vivoantioxidant activity of SP was determined in Wistar rats using the Lipid Peroxidation (LPO) assay in serum. Thein vitroassay was referred to as the TROLOX equivalent antioxidant capacity (TEAC) assay. For thein vivoassay, animals were dosed for 21 consecutive days and blood was drawn to evaluate the MDA level. Thein vitroantioxidant activity of 0.5 μg of SP was equivalent to 14.45 μg of standard TROLOX. The percentage inhibition against the radical formation was50.93±0.53%. The SP showed a statistically significant (p<0.01) decrease in the serum level of thiobarbituric acid-reactive substance in the test rats when compared with the control group. These findings suggest that the SP possesses potent antioxidant activity which may be responsible for some of its reported bioactivities.

Sacha inchi (Plukenetia volubilis) shell is a potential source of phenolics with an-tioxidative activity and its extract can be used to prevent lipid oxidation in some food matrices. However, the sacha inchi extract has been fully exploited due to the dark brown colour properties associated with pigments. Thus, de-colourization of sacha inchi shells before extraction using solvents could be a means to bring about the extract with a lighter colour, which could be applied in foods without constraints. The effects of different solvents used for decolour-ization in sacha inchi (Plukenetia volubilis) shell powder on antioxidant proper-ties were investigated. The solvents used were methanol, acetone, chloroform and propanol. The ethanolic extracts' total phenolic content (TPC) and total flavonoid content (TFC) decreased when solvents were employed for prior de-colourization. Among all solvents, the ethanolic extracts from sacha inchi shell powder decolourized using chloroform (CHE) showed the highest TPC (9.94 mg GAE/g dry extract) and TFC (7.20 mg CE/g dry extract). Also, extracts from chloroform decolourized shell powder had the highest antioxidant activities (2,410.01, 111.60 and 4.58 µmol TE/g dry extract for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scaveng-ing activities, ferric reducing antioxidant power (FRAP), respectively, and 0.52 mmol EDTA /g dry extract for metal chelating assay) compared to other ex-tracts. Therefore, chloroform was the appropriate solvent for decolourization, and the resulting extract had higher antioxidant properties than others.

Abstract Background Lignin is a complex polymer of phenyl propanoid units found in the vascular tissues of the plants as one of lignocellulose materials. Many bacteria secrete enzymes to lyse lignin, which can be essential to ease the production of bioethanol. Current research focused on the study of ligninolytic bacteria capable of producing lignin peroxidase (LiP) which can help in lignin biodegradation and bioethanol production. Ligninolytic bacterial strains were isolated and screened from the soil samples of Simlipal Biosphere Reserve (SBR), Odisha (India), for the determination of their LiP activity. Enzymatic assay and optimization for the LiP activity were performed with the most potent bacterial strain. The strain was identified by morphological, biochemical, and molecular methods. Results In this study, a total of 16 bacteria (Simlipal ligninolytic bacteria [SLB] 1–16) were isolated from forest soils of SBR using minimal salt medium containing lignin. Out of the 16 isolates, 9 isolates showed decolourization of methylene blue dye on LB agar plates. The bacterial isolates such as SLB8, SLB9, and SLB10 were able to decolourize lignin with 15.51%, 16.80%, and 33.02%, respectively. Further enzyme assay was performed using H2O2 as substrate and methylene blue as an indicator for these three bacterial strains in lignin containing minimal salt medium where the isolate SLB10 showed the highest LiP activity (31.711 U/mg). The most potent strain, SLB10, was optimized for enhanced LiP enzyme activity using response surface methodology. In the optimized condition of pH 10.5, temperature 30 °C, H2O2 concentration 0.115 mM, and time 42 h, SLB10 showed a maximum LiP activity of 55.947 U/mg with an increase of 1.76 times from un-optimized condition. Further chemical optimization was performed, and maximum LiP activity as well as significant dye-decolourization efficiency of SLB10 has been found in bacterial growth medium supplemented individually with cellulose, yeast extract, and MnSO4. Most notably, yeast extract and MnSO4-supplemented bacterial culture medium were shown to have even higher percentage of dye decolourization compared to normal basal medium. The bacterial strain SLB10 was identified as Bacillus mycoides according to morphological, biochemical, and molecular (16S rRNA sequencing) characterization and phylogenetic tree analysis. Conclusion Result from the present study revealed the potential of Bacillus mycoides bacterium isolated from the forest soil of SBR in producing LiP enzyme that can be evaluated further for application in lignin biodegradation and bioethanol production. Scaling up of LiP production from this potent bacterial strain could be useful in different industrial applications. Graphical Abstract

Introduction: Mangrove is a complex and unique ecosystem which experiences periodical tidal flooding inundated with low, moderate and high salinity water. Its muddy soil is rich in organic matter derived from the efficient nutrient cycling system and decomposition of mangrove leaves. An adaptation of mangrove microorganisms towards these environmental factors could promote the production of interesting bioactive compounds and enzymes. Methods: This study determines to unravel the identity and biotechnological potential of a Kuantan mangrove actinomycete, strain K3-13, through morphology observation, molecular identification, antimicrobial test and xylan degradation test. Results: The orange-colored mycelium-forming isolates produced spores after a long incubation period, and showed characteristics that resembled Micromonaspora colonies. Phylogenetic analysis of the 16S rRNA gene sequence of strain K3-13 indicated that the highest similarity was to Micromonospora carbonacea DSM43168 (99%). It was observed that K3-13 produced blue diffusible pigment upon cultivation on agar media. Cross streak assay conducted to detect antimicrobial activity indicated that K1-13 has strong antibacterial activity against Bacillus subtilis and Staphylococcus aureus. K3-13 also showed positive xylanase activity by exhibiting decolourization zone in the agar-based assay using azo-xylan as substrate. Conclusions: On the basis of its ability to produce blue pigment, antimicrobial activity against at least two test organisms and positive xylan degrading activity, Micromonaspora K3-13 is concluded as strain worth exploring for its potential biotechnological application as a natural dye, antibacterial drugs and Xylan biodegraders.

Introduction: Mangrove is a complex and unique ecosystem which experiences periodical tidal flooding inundated with low, moderate and high salinity water. Its muddy soil is rich in organic matter derived from the efficient nutrient cycling system and decomposition of mangrove leaves. An adaptation of mangrove microorganisms towards these environmental factors could promote the production of interesting bioactive compounds and enzymes. Methods: This study determines to unravel the identity and biotechnological potential of a Kuantan mangrove actinomycete, strain K3-13, through morphology observation, molecular identification, antimicrobial test and xylan degradation test. Results: The orange-colored mycelium-forming isolates produced spores after a long incubation period, and showed characteristics that resembled Micromonaspora colonies. Phylogenetic analysis of the 16S rRNA gene sequence of strain K3-13 indicated that the highest similarity was to Micromonospora carbonacea DSM43168 (99%). It was observed that K3-13 produced blue diffusible pigment upon cultivation on agar media. Cross streak assay conducted to detect antimicrobial activity indicated that K1-13 has strong antibacterial activity against Bacillus subtilis and Staphylococcus aureus. K3-13 also showed positive xylanase activity by exhibiting decolourization zone in the agar-based assay using azo-xylan as substrate. Conclusions: On the basis of its ability to produce blue pigment, antimicrobial activity against at least two test organisms and positive xylan degrading activity, Micromonaspora K3-13 is concluded as strain worth exploring for its potential biotechnological application as a natural dye, antibacterial drugs and Xylan biodegraders.

Aim: The work was aimed at assessing the potential of Chlorella vulgaris in remediation of reactive dyes. Place and Duration of Study: Department of Biological Sciences, Department of Plant Biology and Department of Biochemistry, Bayero University, Kano, Nigeria, between January 2019 and December 2019. Methodology: Wastewater containing individual reactive dyes: reactive red 198 (RR198), reactive yellow 176 (RY176), reactive green 19 (RG19), reactive orange 122 (RO122), reactive red 195 (RR195) and reactive violet 1 (RV1) were collected from a local fabric re-dyeing pit at Kofar Na’isa, Kano, Nigeria. The green microalga C. vulgaris was cultured in Bold Basal medium (BBM) at 30 ± 2°C and subjected to adsorption and decolourization assays of the dyes. Results: The highest dye removal efficiency by enzymatic action was recorded after 48 hours, while that for the biomass adsorption was at day 14, at pH 11.3 and temperature of 30°C. The percentage dye removal by adsorption and decolourization were within the ranges of 68.1-97.8% and 69.8-99.9% respectively. Dye removal decreased with increase in contact time until saturation is attained. Freundlich’s isotherm model was best fitted for the adsorption of the dyes with a strong linear correlation coefficient, R2 ranging from 0.954-0.811. There was a strong linear relationship and high statistical significance among the dyes for both decolourization and adsorption (P value; .01). Conclusion: Chlorella vulgaris was found to be effective in the removal of reactive dyes from textile wastewater samples. The results revealed C. vulgaris to be a cost-effective and eco-friendly biosorbent that can be used for the treatment of wastewaters containing toxic dyes.

To date, environmental monitoring is mainly focused on traditional chemical techniques, or on the assessment of specific biomarkers. However, these analyses are affected by several limitations: mainly, they are expensive, spot-sampling and time-consuming. In order to overcome these drawbacks, new biological monitoring methods, such as biosensors and biological early warning system (BEWS) are under development. These kinds of devices, built around whole cells, enzymes and antibodies, are well-suited to cooperatively and continuously monitor the environmental conditions. The key-factor of this very promising approach is the biological sensing element. Whole cell systems and enzymes are well suited for environmental monitoring: they are able to determine the bioavailable and toxic concentration of xenobiotics, especially if the source and nature of the compound cannot be predicted. Microorganisms usually detect a broad spectrum of chemicals, and represent a good opportunity for low cost, long shelf-life, and wide range of conditions in which they can be applied. Besides, enzymes are effective when a particular kind of pollutant would be detected because is possible to fine tune their metabolic behaviour by means of protein engineering. In this work, three biological sensing elements, related to three different index of toxicity were evaluated, in order to develop new biosensors for environmental monitoring: a broad toxicity index associated to the decrease of light emission (EC50 or half effective concentration) of a bioluminescent bacterium, Vibrio fischeri, a metal toxicity connected to the metal-regulated production of a siderophore (pyoverdine) by the soil and water microorganism Pseudomonas fluorescens, and finally an index of toxicity given by PAHs, was related to the metabolization of these compounds by laccase of Trametes versicolor. One of the first step during the assessment of a new biological sensing element is the study of the effect of physical-chemical parameters. The tested physical-chemical parameters (temperature, pH, inoculum percentage (v/v) and carbon source) influenced both microbial sensible elements (V. fischeri and P. fluorescens), therefore, these sensible elements can be used in a whole-cell biosensor for in-situ application, even if the response is affected by the environmental variables. Furthermore, the light emission of V. fischeri was highly variable, although a more stable bioluminescence was obtained by means of a glucose fed-batch: this is one step towards the direct application of this system, usually tailored for laboratory assays, to estimate the broad acute toxicity directly in situ in a portable device. Regarding the interaction between P. fluorescens and Fe3+, Cu2+, and Zn2+, the minimum inhibitory concentration (MIC) and the pyoverdine critical concentration (PCC) obtained values were compared to those indicated in the WHO Guidelines for drinking water quality and in European directive 98/83/EC: MICs of Fe3+, Cu2+ and Zn2+ are always above the threshold specified, whilst PCCs are very near to the recommended thresholds for iron and copper. The PCC was not determined for zinc in the tested range of concentration and conditions. These results highlighted that this sensible element should be further investigated for the development of a biosensor able to monitor metals in the environment. The last and most promising sensing element assessed in this work was the lccβ laccase of T. versicolor. A combination of computational docking (SwissDock) and molecular biology techniques was used to generate rationally engineered laccases with increased ability to process large and persistent PAHs. These mutated isoforms were produced by heterologous expression in P. pastoris, successfully purified, and characterized by means of biochemical assays. The activity of the enzymes was initially tested and characterized with phenolic and non phenolic substrates at different pH (3.0-8.0): the best mutated enzyme F162A/L164A (M1) showed an increased specific activity (UI/mg) in comparison with the wild type, in every tested condition. This result was in agreement with those obtained by computational docking simulations (estimated free binding energy), validating the rational design approach. Moreover, decolourization assays of large aromatic dyes, used as model compounds, have shown that the mutated enzymes are reactive towards molecules with chemical structure resembling that of aromatic organic pollutants. By means of example, enzyme mutants with a larger binding pocket (e.g. M1) showed higher activity against triphenylmethane dyes (e.g. Methyl Green), especially without a mediator of the reaction (HBT), and high stability under a variety of temperature conditions (4, 22 °C, room temperature). Therefore, the best enzyme should be integrated on an appropriate transducer (e.g. electrode), and coupled to a wireless platform generating a BEWS for environmental monitoring.