Assessment of C-type halohydrin dehalogenase stability

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Biokataliza u doba zelene revolucije

U dobu zelene revolucije sve više raste svijest o potrebi razvoja održivijih alternativa tradicionalnim industrijskim procesima. Gotovo svi industrijski procesi upotrebljavaju katalizatore koji su nerazgradivi i mogu biti štetni za okoliš. S druge strane, biokatalizatori su enzimi – molekule evoluirale u fiziološkom okruženju koje su u potpunosti biorazgradive, a u blagim reakcijskim uvjetima fiziološkog pH, temperature i tlaka okoline pokazuju najveću katalitičku aktivnost i učinkovitost. Biokatalizu ljudi primjenjuju još od starog vijeka u proizvodnji hrane poput sira, kiselog tijesta, piva, vina i octa bez znanja o pozadini procesa koji se odvija, a u posljednjih nekoliko desetljeća porasla je i njezina primjena u industriji, posebice u proizvodnji lijekova i kemikalija. Prepoznate su sve prednosti koje imaju biokatalizatori, poput njihove velike selektivnosti, velike specifičnosti prema supstratu i biorazgradivosti, te postaje sve jasnije da biokataliza može pomoći ispunjenju ciljeva održivog razvoja i implementaciji zelene kemije u industrijske procese s maksimalnim iskorištenjem resursa uz minimalno stvaranje otpada. Iako biokataliza ispunjava gotovo sva načela zelene kemije i potencijal biokatalizatora eksponencijalno raste razvojem inovacija i tehnološkog napretka, posebno u područjima biotehnologije i molekularne biologije, sama prisutnost biokatalizatora u kemijskom procesu ne podrazumijeva održivost procesa. Ekološku prihvatljivost, ali i ekonomsku isplativost, procesa je potrebno dokazati što ranije tijekom njegova razvoja praćenjem raznih procesnih pokazatelja kako bi se uštedjeli i vrijeme i novac

Application of Mathematical Modelling in Development of Enzymatic Cascade Reactions

“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. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna.Today, systems biocatalysis, i.e., the implementation of cascade reactions that mimic cellular metabolic pathways, is increasingly being used. Cascade reactions have numerous advantages over traditional chemical processes; however, in order to successfully optimize and transfer such complex systems to a larger, industrial scale, it is necessary to apply reaction engineering. This review paper provides examples of the successful application of mathematical modelling in development of enzymatic cascade reactions that demonstrate the importance and potential of this methodology. This work is licensed under a Creative Commons Attribution 4.0 International License

Enzyme Reaction Engineering as a Tool to Investigate the Potential Application of Enzyme Reaction Systems

It is widely recognized and accepted that although biocatalysis is an exquisite tool to synthesize natural and unnatural compounds under mild process conditions, much can be done to better understand these processes as well as detect resulting bottlenecks and help to resolve them. This is the precise purpose of enzyme reaction engineering, a scientific discipline that focuses on investigating enzyme reactions with the goal of facilitating their implementation on an industrial scale. Even though reaction schemes of enzyme reactions often seem simple, in practice, the interdependence of different variables is unknown, very complex and may prevent further applications. Therefore, in this work, important aspects of the implementation of enzyme reactions are discussed using simple and complex examples, along with principles of mathematical modelling that provide explanations for why some reactions do not proceed as planned

Exploring the Variable Sky with LINEAR. III. Classification of Periodic Light Curves

We describe the construction of a highly reliable sample of ~7000 optically faint periodic variable stars with light curves obtained by the asteroid survey LINEAR across 10,000 deg^2 of the northern sky. The majority of these variables have not been cataloged yet. The sample flux limit is several magnitudes fainter than most other wide-angle surveys; the photometric errors range from ~0.03 mag at r = 15 to ~0.20 mag at r = 18. Light curves include on average 250 data points, collected over about a decade. Using Sloan Digital Sky Survey (SDSS) based photometric recalibration of the LINEAR data for about 25 million objects, we selected ~200,000 most probable candidate variables with r < 17 and visually confirmed and classified ~7000 periodic variables using phased light curves. The reliability and uniformity of visual classification across eight human classifiers was calibrated and tested using a catalog of variable stars from the SDSS Stripe 82 region and verified using an unsupervised machine learning approach. The resulting sample of periodic LINEAR variables is dominated by 3900 RR Lyrae stars and 2700 eclipsing binary stars of all subtypes and includes small fractions of relatively rare populations such as asymptotic giant branch stars and SX Phoenicis stars. We discuss the distribution of these mostly uncataloged variables in various diagrams constructed with optical-to-infrared SDSS, Two Micron All Sky Survey, and Wide-field Infrared Survey Explorer photometry, and with LINEAR light-curve features. We find that the combination of light-curve features and colors enables classification schemes much more powerful than when colors or light curves are each used separately. An interesting side result is a robust and precise quantitative description of a strong correlation between the light-curve period and color/spectral type for close and contact eclipsing binary stars (β Lyrae and W UMa): as the color-based spectral type varies from K4 to F5, the median period increases from 5.9 hr to 8.8 hr. These large samples of robustly classified variable stars will enable detailed statistical studies of the Galactic structure and physics of binary and other stars and we make these samples publicly available

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Mathematical modelling of Trametes versicolor growth on different carbohydrates

Gljiva bijelog truljenja Trametes versicolor proizvodi različite izvanstanične enzime od kojih su najpoznatiji lakaze, lignin peroksidaze i mangan peroksidaze. Lakaze (benzenediol: oxygen oxidoreductase, EC 1.10.3.2) su oksidaze koje kataliziraju oksidaciju supstrata prijenosom elektrona i istovremenom redukcijom kisika u vodu. Ekološki su prihvatljive jer im je za katalitičko djelovanje potreban samo kisik iz zraka, pri čemu kao jedini nusproizvod nastaje voda. Kataliziraju reakcije oksidacije velikog broja supstrata. U ovom radu je istraživan uzgoj gljive bijelog truljenja Trametes versicolor u obliku micelijskih peleta na glukozi, fruktozi i saharozi. Rast biomase u submerznim uvjetima šaržnog uzgoja na glukozi i fruktozi opisan je Monodovim kinetičkim modelom. Prilikom rasta gljive na saharozi, pretpostavljeno je da je hidroliza saharoze do glukoze i fruktoze katalizirana invertazom, što je opisano Michaelis-Menteničinom kinetikom, nakon čega slijedi rast gljive paralelno na glukozi i fruktozi. Nadalje, u radu su provedena istraživanja proizvodnje lakaze na otpadu iz industrije papira. Istraženi su utjecaji sastava hranjive podloge (početne koncentracije micelijskih peleta, koncentracije industrijskog otpada, kvaščevog ekstrakta i peptona) na aktivnost enzima lakaze.White-rot fungus Trametes versicolor produces different extracellular enzymes and the best known are laccase, lignin-peroxidase and manganese-peroxidase Laccases (EC 1.10.3.2, p-diphenol: dioxygen oxidoreductases) are oxidases that catalyze substrate oxidation by electron transfer and simultaneous reduction of oxygen to water. They are environmentally ideal while they require only air for their catalytic function and produce water as the only by product. They have a very wide substrate range. In this work the growth of white-rot fungus Trametes versicolor on glucose, fructose and sucrose in a form of mycelial pellets was investigated. Biomass growth in submerged batch conditions on glucose and fructose was described using the Monod kinetic model. It was assumed that, during the biomass growth on sucrose, sucrose enzymatic decomposition to glucose and fructose is catalyzed with invertase which was described with the Michaelis-Menten kinetics. After the sucrose enzymatic decomposition, Trametes versicolor grows simultaneous on glucose and fructose. Furthermore, in this work the production of laccase using waste from paper industry was investigated. The effect of the nutrient medium composition (initial mycelial pellets concentration, initial industrial waste concentration, yeast and peptone concentration) on laccase activity was studied

Mathematical modelling of Trametes versicolor growth on different carbohydrates

Gljiva bijelog truljenja Trametes versicolor proizvodi različite izvanstanične enzime od kojih su najpoznatiji lakaze, lignin peroksidaze i mangan peroksidaze. Lakaze (benzenediol: oxygen oxidoreductase, EC 1.10.3.2) su oksidaze koje kataliziraju oksidaciju supstrata prijenosom elektrona i istovremenom redukcijom kisika u vodu. Ekološki su prihvatljive jer im je za katalitičko djelovanje potreban samo kisik iz zraka, pri čemu kao jedini nusproizvod nastaje voda. Kataliziraju reakcije oksidacije velikog broja supstrata. U ovom radu je istraživan uzgoj gljive bijelog truljenja Trametes versicolor u obliku micelijskih peleta na glukozi, fruktozi i saharozi. Rast biomase u submerznim uvjetima šaržnog uzgoja na glukozi i fruktozi opisan je Monodovim kinetičkim modelom. Prilikom rasta gljive na saharozi, pretpostavljeno je da je hidroliza saharoze do glukoze i fruktoze katalizirana invertazom, što je opisano Michaelis-Menteničinom kinetikom, nakon čega slijedi rast gljive paralelno na glukozi i fruktozi. Nadalje, u radu su provedena istraživanja proizvodnje lakaze na otpadu iz industrije papira. Istraženi su utjecaji sastava hranjive podloge (početne koncentracije micelijskih peleta, koncentracije industrijskog otpada, kvaščevog ekstrakta i peptona) na aktivnost enzima lakaze.White-rot fungus Trametes versicolor produces different extracellular enzymes and the best known are laccase, lignin-peroxidase and manganese-peroxidase Laccases (EC 1.10.3.2, p-diphenol: dioxygen oxidoreductases) are oxidases that catalyze substrate oxidation by electron transfer and simultaneous reduction of oxygen to water. They are environmentally ideal while they require only air for their catalytic function and produce water as the only by product. They have a very wide substrate range. In this work the growth of white-rot fungus Trametes versicolor on glucose, fructose and sucrose in a form of mycelial pellets was investigated. Biomass growth in submerged batch conditions on glucose and fructose was described using the Monod kinetic model. It was assumed that, during the biomass growth on sucrose, sucrose enzymatic decomposition to glucose and fructose is catalyzed with invertase which was described with the Michaelis-Menten kinetics. After the sucrose enzymatic decomposition, Trametes versicolor grows simultaneous on glucose and fructose. Furthermore, in this work the production of laccase using waste from paper industry was investigated. The effect of the nutrient medium composition (initial mycelial pellets concentration, initial industrial waste concentration, yeast and peptone concentration) on laccase activity was studied

1st Croatian Biospeleological expedition - Biokovo 2017

Biokovo Mountain in Croatia is a Dinaric hotspot of subterranean biodiversity and its area of 196 km 2 is protected as a nature park. Until now, more than 400 caves have been registered here, however, only in about 30% of them biospeleological research has been carried out. It is hypothesized that over 1000 caves exist in highly karstified Biokovo Mt. Biospeleological research of the area started at the beginning of 20th century and deep caves were infrequently explored after the year 1980. Previous research recorded more than 90 troglobiotic species in this area and most of them are endemic. The primary goal of the Expedition was a systematic survey of eight deep caves (depth over 250 m), one of which was never before biospeleologically surveyed. We also surveyed other caves from which material for detailed faunistic analysis was missing. The main part of the expedition took place from 17 th to 25 th June 2017, with 52 participants. Fauna was collected by hand and by pitfall traps with baits, in the total of 26 caves. Five deep caves were completely surveyed (depth up to 710 m), the topographic map was made when missing, and fauna was photographed. Microclimatic conditions were measured and in two caves data loggers were placed. According to preliminary results, around 10 new species for science have been found from following groups: leeches (Hirudinea), spiders (Araneae), harvestmen (Opiliones), woodlice (Isopoda), centipedes (Chilopoda), springtails (Collembola), two-pronged bristletails (Diplura) and beetles (Coleoptera). These results confirm that deep caves of Biokovo Mt are still underexplored and that detailed and systematic research is needed.