Academic literature on the topic 'Biokataláza'

“Sustavska biokataliza” (engl. systems biocatalysis), odnosno provedba kaskadnih reakcija koje oponašaju stanične metaboličke puteve danas se sve češće primjenjuje. Kaskadne reakcije imaju brojne prednosti nad tradicionalnim kemijskim postupcima, međutim, za uspješnu optimizaciju i prenošenje takvih kompleksnih sustava u veće, industrijsko mjerilo potrebno je primijeniti reakcijsko inženjerstvo. U ovom preglednom radu navedeni su primjeri uspješne primjene matematičkog modeliranja na razvoj enzimskih kaskadnih reakcija koji pokazuju važnost i potencijal te metodologije.

Zbog bolje učinkovitosti i sigurnosti potreba za enantiomerno čistim kiralnim spojevima u stalnom je porastu, pogotovo u farmaceutskoj industriji. Da bi se te potrebe zadovoljile potrebne su nove, učinkovitije i jeftinije ali i ekološki prihvatljive metode njihove priprave. U skladu s tim veliku je pažnju privukla biokataliza gdje se kao biokatalizatori koriste mikroorganizmi ili enzimi izolirani iz njih. Posljednjih godina znanstvena zajednica se okrenula istraživanju upotrebe svježeg, netaknutog biljnog materijala kao biokatalizatora. Upotreba biljnog materijala ne zahtijeva dodatak skupih kofaktora budući da se različiti enzimski sustavi i potrebni kofaktori, te njihov regeneracijski sustav već nalaze u biljnom tkivu. Ovisno o upotrijebljenoj biljci (voću, povrću, začinima), pojedini enantiomeri se mogu dobiti u visokom prinosu i s visokim enantiomernim viškom, što je kritični faktor za razvoj biološki aktivnih spojeva i njihovu bioaktivnost. U ovom radu dan je pregled istraživanja potencijalne upotrebe različitih biljnih vrsta i njihovih dijelova kao biokatalizatora u stereoselektivnim transformacijama pogodnih spojeva s ciljem dobivanja novih enentiomerno čistih spojeva. Primjena biljnih biokatalitičkih sustava u skladu je s principima zelene kemije i predstavlja značajnu alternativu sintetskim kemijskim postupcima.

For a sustainable future, there is a call to increase the market share of bio-based technologies and materials. Microbial-based technologies have the potential and the ability to contribute substantively on many levels to global efforts to achieve sustainability. Development and utilization of microbial technologies is, however, an extensive process involving numerous steps, including the discovery of novel technologies and the development of industrially viable production systems. In the presented thesis, individual steps of microbial biotechnology development were addressed. In the first part of the study, a variety of methodological approaches were employed in order to study the effect of the anthropogenic activity (i.e., decades lasting production of penicillin G) on the structure of soil microbial communities. Moreover, both cultivable and non-cultivable fractions of populations were subjected to functional screening in order to unravel the biotechnological potential of the microorganisms in terms of production of enzymes involved in biotransformation of beta-lactam antibiotics: penicillin G acylase (PGA) and alpha amino acid ester hydrolase (AEH). Our results indicated that the impacted communities harbour a microbial community with increased diversity and richness. However, on the...

Nitrilases are enzymes which catalyze the hydrolysis of nitriles to corresponding carboxylic acids. These enzymes have a great potential in biocatalysis, for example in the synthesis of mandelic acid and mandelamide, because of their chemo- and enantioselectivity. As bioremediation agents they are also applicable to sites contaminated with organic nitriles. In this work, activities of recombinant strains of E. coli expressing hypothetical nitrilases from fungi Giberella moniliformis and Nectria haematococca mpVI 77-13-4 were studied, as well as the biodegradation potential of bacteria from Rhodococcus and Nocardia genera towards benzonitrile herbicides dichlobenil (2,6-dichlorobenzonitrile), ioxynil (3,5-diiodo-4- hydroxybenzonitrile) and bromoxynil (3,5-dibromo-4-hydroxybenzonitrile). The hypothetical fungal nitrilases were expressed as functional enzymes. Nitrilase from G. moniliformis showed highest activity towards benzonitrile (30.9 U/mg protein), total activity yield was 2,560 U/l cell culture. The preferred substrate of the nitrilase from N. haematococca was phenylacetonitrile (12.3 U/mg prot.), total activity yield was 28,050 U/l cell culture. Nitrilase from N. haematococca was also able to hydrolyze mandelonitrile (5.9 U/mg prot.). Soil bacteria Rhodococcus rhodochrous PA-34, Nocardia globerula...

Nitrilases are enzymes which catalyze the hydrolysis of a nitrile into the corresponding carboxylic acid and ammonia. These enzymes are potentially applicable in biocatalysis and bioremediation because of their advantages over the conventional (chemical) methods of nitrile hydrolysis (lower demand for energy, safety, simplicity, high yields, selectivity). In this work, genome mining was used to search for the sequences of hypothetical nitrilases from filamentous fungi. The amino acid sequences of previously characterized fungal nitrilases were used as the templates. Then the new synthetic genes together with other genes from our nitrilase library were expressed in E. coli and the substrate specificities of the enzymes thus produced were compared. Significant attention was focused on the relationships between the sequence of the enzyme and its substrate specificity. The arylacetonitrilases from Arthroderma benhamiae (NitAb) and Nectria haematococca (NitNh) were purified and characterized. Their substrate specificities, kinetic parameters, pH and temperature profiles and subunit and holoenzyme size were assessed. NitAb and NitNh together with other recombinant fungal nitrilases were employed in the hydrolysis of high concentrations of (R,S)-mandelonitrile in a batch or fed-batch mode. Nitrilase from...

11 Abstract Penicillin G acylases (PGAs) belong among enantioselective enzymes catalyzing a hydrolysis of stable amide bond in a broad spectrum of substrates, often having high application potential. PGAEc from Escherichia coli and PGAA from microorganism Achromobacter sp. CCM 4824 were used to catalyze enantioselective hydrolyses of seven selected N-phenylacetylated (N-PhAc) α/β-amino acid racemates. The PGAA showed higher stereoselectivity for three (S) enantiomers: N-PhAc-β-homoleucine, N-PhAc-α-tert- leucine and N-PhAc-β-leucine. We have constructed a homology model of PGAA that was used in molecular docking experiments with the same substrates. In-silico experiments reproduced the data from experimental enzymatic resolutions confirming validity of employed modeling protocol. We employed this protocol to evaluate enantiopreference of PGAA towards seven new substrates with application potential. For five of them, high enantioselectivity of PGAA was predicted for. PGAA was further studied in kinetically controlled syntheses of β-lactam antibiotics (SSBA). The PGAA was significantly more efficient at synthese of ampicillin and amoxicillin (higher S/H ratio and product accumulation) compared with PGAEc . Analogously to prediction of enantioselectivity of PGAA towards new substrates this protocol was applied...