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Investigation of mixing efficiency inside microreactors using integrated pH-sensing films
No full textCilj ovog rada bio je pripremiti pH-senzorski film na osnovi lakmusa i metil crvenog sol-gel postupkom uz tetraetoksisilan (TEOS) i feniltrimetoskisilan (FTMS) kao prekursore. Zatim primijeniti pripremljene filmove u mikroreaktorima sa i bez statičkih miješalica 3D-ispisanih stereolitografijom (engl. Stereolithography, SLA) od High Temp smole i digitalnom obradom svjetla (engl. Digital Light Processing, DLP) od Anycubic Basic smole s ciljem ispitivanja efikasnosti miješanja. Pripremljeni pH-senzorski filmovi karakterizirani su mjerenjem kontaktnog kuta na goniometru uz vodu i dijodometan kao testne kapljevine. Efikasnost miješanja pratila se promjenom boje pH-senzorskog filma analizom fotografija mikroreaktora tijekom istraživanja u programu Color Picker AR i određivanjem vrijednosti h (engl. hue). Ispitivanje efikasnosti miješanja provedeno je na način da su se u kanalima mikroreaktora u kontakt dovodile otopine pH-vrijednosti 2 i 11, 2 i 7 te 7 i 11 pri jednakom protoku. Najuočljivija promjena boje pH-senzorskog filma i posljedično najbolje praćenje efikasnosti miješanja postignuto je korištenjem otopina pH 2 i 11. Efikasnost miješanja se s navedenom kombinacijom otopina pratila tijekom 20 ciklusa u trajanju od 2 min prilikom čega je u svakom ciklusu jedna od otopina bila u suvišku. pH-senzorski film na osnovi lakmusa i metil crvenog nije pokazivao promjenu boje u otopinama različitih pH-vrijednosti pa je za ispitivanje efikasnosti miješanja korišten film na osnovi lakmusa i titanijevog dioksida, TiO2. Promjena boje pH-senzorskog filma odvijala se nakon jedne minute, a film je pokazivao promjenu boje tijekom cijelog istraživanja čime se potvrdila mogućnost njegove višestruke upotrebe. Ispitivanjem efikasnosti miješanja zaključeno je da u mikroreaktorima sa statičkim miješalicama dolazi do poboljšanja miješanja otopina.The aim of this research was to prepare pH-sensor film based on litmus and methyl red by sol-gel method with tetraethoxysilane (TEOS) and phenyltrimethoxysilane (PTMS) as precursors and to apply prepared pH-sensor film in microreactors without and with two types of static mixers for investigation of mixing efficiency. Microreactors made of High Temp resin were 3D printed by stereolithography (SLA) and microreactors made of Anycubic Basic resin were 3D printed by digital light processing (DLP). Prepared pH-sensor films were characterized by measuring contact angle using water and diiodomethane as test liquids. Mixing efficiency was observed through color change of pH-sensor films and determining hue value in program Color Picker AR. The research was carried out in a way that solutions of pH values of 2 and 11, 2 and 7 and 7 and 11 were mixed inside channels of microreactors at an equal flow rate. The most notable color change of pHsensor film and consequently the best monitoring of mixing efficiency was achieved using solutions of pH 2 and 11. Mixing efficiency was observed with that combination of solutions during 20 cycles lasting 2 minutes. In every cycle, one of the solutions was in excess. pH-sensor film based on litmus and methyl red did not show color change in solutions of different pH values so it was not used in mixing efficiency tests. Instead, pH-sensor film based on litmus and titanium dioxide, TiO2 was used. pH-sensor film changed color after 1 minute and the film showed color change during entire duration of research. This showed that the film can be used multiple times. By observing mixing efficiency, it was concluded that there is an improvement in mixing in microreactors with static mixers
Influence of 3D printing parameters on chemical and mechanical properties of polyvinyl butyral and thermoplastic polyuretane
No full textAditivna proizvodnja je proces trodimenzionalog ispisivanja tijela prethodno dizajniranog u računalnom programu koji se temelji na nanošenju materijala sloj po sloj do konačnog proizvoda. Proizvodnja rastaljenim filamentom jedan je od postupaka aditivne proizvodnje koji se temelji na nanošenju zagrijanog materijala sloj po sloj. Ovim postupkom 3D-ispisane su epruvete od poli(vinil-butirala) i plastomernog poliuretana pod kutovima 0° i 45° u različitim debljinama sloja. U svrhu karakterizacije 3D-ispisanih dijelova izrađenih različitim debljinama slojeva i pod različitim kutovima provedeno je mehaničko ispitivanje statičkim vlačnim testom. Provedeno je ispitivanje kemijskih svojstava testom bubrenja kako bi se ispitala topljivost ovih materijala u različitim otapalima i FTIR analiza za potvrdu kemijskog sastava uzorka. Ispitivanje toplinskih svojstava istraženo je razlikovnom pretražnom kalorimetrijom. Rezultati ispitivanja svojstava pokazali su kako uzorci ispisani pod kutom od 0° imaju veću vlačnu čvrstoću od uzoraka ispisanih pod kutom od 45°. Testom bubrenja utvrđena su otapala u kojima materijali najviše bubre, a FTIR analizom potvrđene su karakteristične skupine za oba materijala. Razlikovnom pretražnom kalorimetrijom utvrđeno je da plastomerni poliuretan sadrži amorfnu i kristalnu fazu, dok poli(vinil-butiral) pokazuje amorfna svojstva.Additive manufacturing is the process of three-dimensional printing of a body previously designed in a computer program. Fused filament fabrication is one of the processes of additive manufacturing, which is based on the application of heated material layer by layer to the desired model. Using this process, test tubes made of poly(vinyl-butyral) and thermoplastic polyurethane were printed at angles of 0° and 45° in different layer thicknesses. For the purpose of characterizing 3D-printed parts made with different layer thicknesses and at different angles, mechanical a static tensile tests were performed. Chemical properties were tested by swelling test to test the solubility of these materials in different solvents and FTIR analysis was perfomed to confirm the chemical composition of the sample. Thermal properties were tested by differential scanning calorimetry. The test results showed that samples printed at an angle of 0° have higher tensile strength than samples printed at an angle of 45°. The swelling test determined the solvents in which the materials swell the most, and the FTIR analysis confirmed the characteristic groups for both materials. Differential scanning calorimetry showed that thermoplastic polyurethane contains amorphous and crystalline phases, while poly(vinyl-butyral) shows amorphous properties
Production, properties and recycling of polyethylene terephthalate bottles
No full textPoli(etilen-tereftalat) jedan je od najviše primjenjivanih polimera u posljednja dva desetljeća, a potražnja za njim kroz godine sve više raste. Odlična svojstva, kao što su visoko talište, niska propusnost na plinove (vodenu paru, O2, CO2), inertnost prema otapalima i kemikalijama, čvrstoća i tvrdoća, žilavost i toplinska stabilnost, omogućuju mu primjenu u brojnim industrijskim granama. Široka mu je primjena u prehrambenoj, tekstilnoj, automobilskoj i građevinskoj industriji pa i u medicini, ali najvažniju primjenu nalazi u izradi PET boca koje su tijekom godina postale najvažnijim proizvodom PET-a. Proizvodnja PET boca odvija se dvama procesima, a oni su injekcijsko prešanje PET predoblika i razvlačno puhanje PET boca koji se mogu odvijati u jednoj ili dvije zasebne faze. Injekcijskim prešanjem rastaljeni se PET ubrizgava u kalupne šupljine gdje poprima oblik predoblika te se kao takav izbacuje iz kalupa, a potom se razvlačnim puhanjem formira u PET boce. Tako nastale boce imaju primarnu ulogu u pakiranju obične i mineralne vode te bezalkoholnih gaziranih pića, no vremenom su postale i ambalaža za pakiranje drugih proizvoda poput mlijeka i mliječnih proizvoda, voćnih sokova, piva, lijekova, kemikalija, kozmetičkih proizvoda, sredstava za čišćenje, umaka, začina i sl. Jedan od glavnih razloga tako široke primjene PET boca mogućnost je njihovog potpunog recikliranja koje je izrazito bitno s obzirom da PET sudjeluje u stvaranju velike količine plastičnog otpada. Prije samog postupka recikliranja, potrebno je provesti pripremu za recikliranje koja se sastoji od sakupljanja, razvrstavanja, usitnjavanja, pranja i sušenja PET boca. Najzastupljeniji postupci recikliranja su mehaničko i kemijsko recikliranje, a kemijsko se recikliranje može provesti metanolizom, hidrolizom ili glikolizom.Polyethylene terephthalate is one of the most used polymers in the last two decades, with its demand increasing over the years. Its excellent properties, such as high melting temperature, low gas permeability (water vapor, O2, CO2), inertness to solvents and chemicals, strength and hardness, toughness and thermal stability, allow it to be used in numerous industrial branches. It is widely used in food, textile, automotive and construction industries as well as in medicine but its most important application is in the production of PET bottles, which have become the most important PET product over the years. The production of PET bottles is carried out by two processes: injection molding of PET preforms and stretch blow molding of PET bottles, which can take place in one or two separate phases. In the injection molding process, molten PET is injected into mold cavities where it takes the shape of a preform. These preforms are then ejected from the mold and formed into the PET bottles through stretch blow moulding. These bottles have a primary role in the packaging of still and mineral water and soft carbonated drinks, but over time they have also become packaging for other products such as milk and dairy products, fruit juices, beer, pharmaceuticals, chemicals, cosmetic products, cleaning agents, sauces, spices etc. One of the main reasons for the widespread use of PET bottles is their ability to be fully recycled, which is extremely important considering that PET is involved in generating large amounts of plastic waste. Before the actual recycling process, it is necessary to carry out preparation for recycling, which consists of collecting, sorting, shredding, washing and drying of PET bottles. The most common recycling methods are mechanical and chemical recycling, with chemical recycling being carried out through methanolysis, hydrolysis or glycolysis
UV degradation of PLA biocomposites reinforced with olive waste (wood andleaves)
No full textU svrhu ovog rada provedena je UV razgradnja biokompozita proizvedenih od poli(mliječne kiseline) (PLA) s dodatkom otpada masline u različitim udjelima (2,5%, 5%, 7,5% i 10 mas.%), bez i s dodatkom plastifikatora trietil citrata (TEC) u udjelu od 20 mas.%. Cilj je istražiti utjecaj UV zračenja na svojstva PLA biokompozita koji se mogu koristiti kao ambalažni materijali zbog njihove zdravstvene i ekološke sigurnosti. Svi uzorci su podvrgnuti UV razgradnji tijekom 720h. Promjene u strukturi nakon UV zračenja praćene su Infracrvenom spektroskopijom s Fourierovom transformacijom (FTIR) dok su toplinska svojstva određena diferencijalnom pretražnom kalorimetrijom (DSC). Rezultati su pokazali da UV razgradnja utječe na kemijsku i toplinsku stabilnost biokompozita, što ima značajan utjecaj na njihovu dugovječnost i primjenjivost kao ambalažnog materijala.This study investigated the UV degradation of biocomposites made from poly(lactic acid) (PLA) with the addition of olive waste at various content (2.5%, 5%, 7.5%, and 10 wt.%), withouth and with the addition of the plasticizer triethyl citrate (TEC) at a concentration of
20 wt%. The aim was to investigated the effect of UV irradiation on the properties of PLA biocomposites that can be used as a packaging material due to their health and environmental safety. All samples were subjected to UV degradation over a period of 720h to examine the changes caused by photodegradation. Measurements were conducted using Fourier Transform Infrared Spectroscopy (FTIR) to investigate structural changes induced by UV irradiation, and Differential Scanning Calorimetry (DSC) to determine thermal properties. The results indicated that UV degradation affects the chemical and thermal stability of the biocomposites, which has a significant impact on their longevity and suitability as packaging materials
Isotope ratio mass spectrometry in environmental forensics
No full textForenzika okoliša bavi se istragama onečišćenje okoliša sa svrhom određivanja vrste onečišćivala, pripadajućega izvora onečišćenja i samog počinitelja. Onečišćenje okoliša koje se smatra kažnjivim dijelom, narušava okoliš i zdravlje organizama. Jedna od analitičkih tehnika koju istražitelji koriste prilikom traganja za izvorom onečišćenja u okolišu je masena spektrometrija omjera izotopa. Masenom spektrometrijom omjera izotopa nastoji se odrediti izotopni sastav neke tvari na temelju stabilnih izotopa lakših elemenata. Stabilni izotopi koji su prisutni u tvarima, služe kao prostorni obilježivači ili forenzički rečeno izotopni otisci prstiju.
Na temelju izotopnih otisaka moguće je ući u trag onečišćenja policikličkih aromatskih ugljikovodika, kloriranih alifatskih ugljikovodika, polikloriranih aromatskih ugljikovodika,
n-alkanima, metil-tertbutil eteru, pesticidima, eksplozivima i drugim onečišćivalima u okolišu. Cilj ovoga rada je opisati tehniku masene spektrometrije omjera izotopa kao forenzički alat u rješavanju postojećih onečišćenja okoliša.Environmental forensics deals with environmental pollution investigations with the purpose of determining the type of pollutant, the associated source of pollution and the perpetrator. Environmental pollution, which is considered a punishable offense, damages the environment and the health of organisms. One of the analytical techniques that investigators use when searching for the source of pollution in the environment is isotope ratio mass spectrometry. Isotope ratio mass spectrometry is used to determine the isotopic composition of a substance based on stable isotopes of lighter elements. Stable isotopes that are present in substances serve as spatial markers or, in forensic terms, isotopic fingerprints. On the basis of isotopic prints, it is possible to trace the pollution of polycyclic aromatic hydrocarbons, chlorinated aliphatic hydrocarbons, polychlorinated aromatic hydrocarbons, n-alkanes, methyl-tertbutyl ether, pesticides, explosives and other pollutants in the environment. The aim of this paper is to describe the isotope ratio mass spectrometry technique as a forensic tool in solving existing environmental pollution
Synthesis, characterization and biological investigation of new indene systems
No full textGlavni cilj ovog rada je sintetizirati i okarakterizirati nove derivate indena te ispitati njihovu biološku aktivnost na nekoliko mikrobnih specija. Sintetski put derivata odvijao se u dva koraka. U prvom koraku dobiveni su derivati 1-3 koji reakcijom redukcije daju konačne produkte 4-6. Produkti su izolirani uz pomoć kolonske kromatografije te su u potpunosti spektroskopski okarakterizirani. Svim sintetiziranim spojevima ispitana je antimikrobna aktivnost na specije Bacillus subtilis 3020, Pseudomonas aeruginosa 3011, Candida lipolytica 59 i Aspergillus niger 405.The main objective of this study is to synthesize and characterize new indene derivates and to test their biological activity on certain microbes. The synthetic pathway of the derivative took place in two steps. In the first step, derivatives 1-3 were obtained, to give the final products 4-6 through the reduction reaction. The products are isolated by column chromatography and spectroscopically characterized. All synthesized compounds were tested for antimicrobial activity against the species Bacillus subtilis 3020, Pseudomonas aeruginosa 3011, Candida lipolytica 59 and Aspergillus niger 405
Application of nanocomposites in aerospace technology
No full textOvaj rad razmatra ključne zahtjeve za materijale u zrakoplovstvu, kao i svojstva koja oni moraju imati kako bi se osigurala visoka sigurnost, pouzdanost i optimalne performanse tijekom leta. Glavni predmet interesa su nanokompoziti koji kombiniraju punila nanometarskih veličina s polimernim, keramičkim ili metalnim matricama. Ovi materijali donose značajna poboljšanja u odnosu na konvencionalne kompozite i pojedinačne komponente, nudeći izvrsna mehanička, električna i toplinska svojstva te visoku otpornost na koroziju i trošenje. Rad daje pregled višefunkcionalnih svojstava nanokompozita koja, između ostalog, proizlaze iz homogene disperzije nanopunila u matrici te razmatra njihove primjene u zrakoplovstvu. Prikazana je moguća primjena nanokompozita u baznim strukturnim dijelovima, komponentama pogonskih i senzorskih sustava, zaštitnim premazima te unutrašnjosti zrakoplova. Nekoliko specifičnih primjera modernih zrakoplova ilustrira kako integracija nanokompozita može unaprijediti performanse i pružiti uvid u buduće trendove istraživanja unutar zrakoplovne industrije.This paper examines the key requirements for aerospace materials, and the properties they must possess to ensure high reliability, safety and optimal performance during flight.
The primary focus is on nanocomposites which combine nanoscale fillers with polymer, ceramic or metal matrices. These materials offer significant improvements over conventional composites or individual components, including excellent mechanical, electrical and thermal properties as well as high resistance to corrosion and wear. The paper reviews the multifunctional properties of nanocomposites, which, among other factors, result from the homogeneous dispersion of nanofillers in the matrix and considers their applications in aerospace. The potential use of nanocomposites in structural components, propulsion and sensor system, protective coatings, and aircraft interiors is presented. Several specific examples of modern aircraft illustrate how the integration of nanocomposites can enhance performance and provide insight into future research trends within the aerospace industry
Biological activity of bioactive glasses in the field of tissue engineering
No full textInženjerstvo koštanog tkiva interdisciplinarno je područje koje razvija materijale i metode za liječenje, popravljanje i zamjenu oštećenog koštanog tkiva. Bioaktivno staklo je materijal koji pokazuje odlična svojstva za primjenu u inženjerstvu koštanog tkiva. Bioaktivnost, osteoinduktivnost i osteoproduktivnost svojstva su koja mu omogućuju stvaranje direktne veze s tkivom. Reakcijom bioaktivnog stakla u fiziološkom okruženju dolazi do razgradnje stakla i otpuštanja iona koji potiču okoštavanje i aktiviraju bitne gene. Optimiranjem karakteristika bioaktivnog stakla poput sastava, mikrostrukture i makrostrukture može se značajno utjecati na bioaktivna svojstva materijala. Posebice je zanimljiva raznolikost u sastavu što se tiče odabira kemijskih elemenata, udjela i koncentracija pojedinih komponenata, koji se pažljivo optimiraju kako bi se postigla željena svojstva. Ovim završnim radom dan je uvid u strukturu i svojstva bioaktivnih stakala koja se primjenjuju u području inženjerstva koštanog tkiva, a osobito onih koja imaju najvažniju ulogu u stvaranju direktne veze s koštanim tkivom.Bone tissue engineering is an interdisciplinary field that develops methods to treat, repair, and replace damaged bone tissue. Bioactive glass is a material that shows excellent properties for use in bone tissue engineering. Bioactivity, osteoinductivity and osteoconductivity are properties that enable it to form a direct bond with the tissue.
The reaction of bioactive glass in a physiological environment leads to the degradation of glass and the release of ions that promote ossification and activate relevant genes.
By optimizing the characteristics of bioactive glass, such as composition, microstructure and macrostructure, the bioactive properties can be significantly influenced. The variety in the composition is particularly interesting as regards the selection of chemical elements, the ratio and concentration of individual components, which are carefully optimized in order to achieve the desired properties. This paper provides insight into the structure and properties of bioactive glasses that are used in the field of bone tissue engineering, especially those that play the most important role in creating a direct bond with bone tissue
Biodegradation of polystyrene microplastic particles by bacterial culture of Bacillus cereus
No full text''Tradicionalna'' plastika koju dobivamo iz ugljena, prirodnog plina i nafte jedna je od ekološki štetnijih tvari koje proizvodi čovjek, no ona je vrlo važna i koristna za izgradnju kvalitetnog životnog okruženja. Plastika je iznimno primjenjiv materijal; transparentan, isplativ, lagan, jak i izdržljiv, te posjeduje svojstva koja ga čine korisnima u medicini, poljoprivredi, domaćinstvu te u industrijskoj primjeni. Iako su navedena svojstva poželjna, vrlo stabilna struktura plastike otežava proces biorazgradnje. Plastični materijali se prekomjerno koriste, neodgovorno odbacuju te kao takvi opstaju u tlu, moru i slatkovodnim ekosustavima te se razlažu na manje čestice. Sve plastične čestice manje od 5 mm nazivaju se mikroplastikom (MP). Kroz godine istraživanja, utvrđeni su štetni učinci aditiva koji se dodaju plastici tijekom procesa proizvodnje. Stoga je od izuzetne važnosti pronaći učinkovitu metodu uklanjanja mikroplastike iz okoliša. Sadašnje znanje o aerobnoj biorazgradnji ističe potencijal mikrobnih kultura za uklanjenje mikroplastike iz okoliša. U ovom radu ispitala se biorazgradnja polistirena (PS) primjenom bakterijske kulture Bacillus cereus pri određenim optimalnim uvjetima. Plan eksperimenta biorazgradnje dizajniran je prema punom faktorskom planu. Na temelju preliminarnih pokusa odredili su se značajni čimbenici za biorazgradnju PS-a. Tijekom procesa pratio se broj izraslih stanica bakterija (CFU), koncentracija ukupnog organskog ugljika (TOC), ukupnog ugljika (TC) i anorganskog ugljika (IC) te je provedena LC/MS analiza u svrhu identificiranja otpuštenih aditiva s površine MP-a ili nastalih razgradnih organskih produkata. Uzorci su okarakterizirani FTIR-ATR analizom. Na kraju svih procesa biorazgradnje ispitana je i ekotoksičnost filtrata primjenom bakterije Vibrio fischeri radi utvrđivanja postojećih potencijalnih štetnih učinaka na ispitivani organizam. Eksperimentalni rezultati obrađeni su korištenjem statističke analize varijance (ANOVA). Rezultati pokusa ukazuju da je bolji rast bakterije Bacillus cereus uočen pri najmanjoj veličini čestica (<300 μm), najmanjoj vrijednosti koncentracije (50 mg/L) i najnižem broju okretaja (100 o/min). S obzirom na navedene optimalne uvjete, ispitivana bakterijska kultura ima sposobnost biorazgradnje MP-a."Conventional" plastic, derived from coal, natural gas and petroleum, is one of the most polluting substances produced by man, but it is very important and useful for building a livable environment. Plastic is extremely versatile, transparent, inexpensive, lightweight, strong and durable, and has properties that make it useful in medicine, agriculture, household and industry. Although these properties are desirable, a very stable plastic structure makes biodegradation difficult. Plastics are overused, irresponsibly discarded, and thus survive in soil, marine, and freshwater ecosystems where they decompose into smaller particles. All plastic particles smaller than 5 mm are called microplastics. Over the years, research has identified the harmful effects of additives added to plastics during the production process. Therefore, it is extremely important to find an effective method to remove microplastics from the environment. Current knowledge on biotechnological aerobic biodegradation shows the potential of microbial cultures to remove microplastics from the environment. In this work, the biodegradation of polystyrene (PS) was studied using a bacterial culture of Bacillus cereus under certain optimal conditions. The experimental design for biodegradation was designed according to the Full Factorial Plan. Based on preliminary experiments, important factors for the biodegradation of PS were determined. During the experiments, the colony forming number (CFU), the concentration of total organic carbon (TOC), total carbon (TC) and inorganic carbon (IC) were monitored, and LC / MS analysis was performed to identify the additives released from the surface of MP and the resulting organic degradation products. Samples were characterized by FTIR-ATR analysis. At the end of all biodegradation processes, the ecotoxicity of the filtrate was tested using Vibrio fischeri to determine the potential adverse effects present on the test organism. The experimental results were evaluated using statistical analysis of variance (ANOVA). The experimental results show that better growth of the bacterium Bacillus cereus was observed at the smallest particle size (< 300 μm), the smallest concentration value (50 mg/L) and the lowest rotation speed (100 rpm). Under the mentioned optimal conditions, the tested bacterial culture was able to biodegrade MPs
Evaluation of nitrilases as biocatalysts for the synthesis of (R)-4-chloro-3-hydroxybutyric acid
No full textEnzimi nitrilaze kataliziraju reakcije hidrolize nitrila u karboksilne kiseline i amonijak, bez stvaranja slobodnih amidnih međuprodukata. Iz tog razloga nitrilaza se može koristiti kao biokatalizator u reakcijama pretvorbe (R)-4-klor-3-hidroksibutironitrila (KHB) u (R)-4-klor-3-hidroksibutansku kiselinu, pri čemu dolazi do spontane ciklizacije produkta u (R)-3-hidroksi-γ-butirolakton (HBL). HBL se koristi u sintezi različitih polimera, otapala i farmaceutika kao kiralni građevni blok. Enzimski katalizirani procesi sve se češće primjenjuju za sintezu HBL-a jer koriste blage reakcijske uvjete, postižu visoku selektivnost te mogu pružiti ekonomski isplativ postupak sinteze ove vrijedne kemikalije. Brojni, već postojeći kemijski putevi sinteze HBL-a, pokušavaju se što manje koristiti jer ih većina ima nedostatke poput skupih ili opasnih reaktanata, intenzivnih procesnih uvjeta, te niskih iskorištenja i selektivnosti, što uzrokuje poskupljenje procesa izdvajanja produkta. U ovom radu provedena je evaluacija 24 nitrilaze u reakciji sinteze HBL-a. Tijekom ispitivanja korišteni su isti početni uvjeti, koncentracija supstrata (KHB) i masena koncentracija nitrilaza te je reakcija praćena 6 sati. Enzim s najvećim iskorištenjem na produktu izabran je za sljedeći korak, kinetičko istraživanje. Određeni su kinetički parametri, nitrilazom katalizirane sinteze (R)-4-klor-3-hidroksibutanske kiseline iz (R)-4-klor-3-hidroksibutironitrila, iz kojih je razvijen matematički model. Sastoji se od kinetičkog modela i bilanci tvari u reaktoru. Utvrđeno je da enzim ima nizak afinitet prema supstratu te da reakcija prati Michaelis-Menteničinu kinetiku uz inhibicijski učinak supstrata i produkta. Model je uspješno validiran provedbom reakcije u šest različitih kotlastih reaktora s različitim početnim uvjetima u reaktoru. Uzorci reakcijske smjese su analizirani na tekućinskom kromatografu visoke djelotvornosti i plinskom kromatografu. Iz navedenih eksperimenata procijenjena je konstanta deaktivacije te je zaključeno da početni uvjeti u reaktoru utječu na stabilnost enzima.Nitrilases catalyze nitrile hydrolysis reactions to carboxylic acids and ammonia, without the formation of free amide intermediates. For this reason, nitrilases can be used as a biocatalyst in conversion reactions (R)-4-chlorine-3-hydroxybutyronitrile (KHB) into (R)-4-chlorine-3-hydroxybutane acid, where spontaneous cycling of the product occurs in (R)-3-hydroxy-γ-butyrobactone (HBL). HBL is used in the synthesis of various polymers, solvents and pharmaceuticals as a chiral building block. Enzyme catalyzed processes are increasingly used for the synthesis of HBL because of the mild reaction conditions, high selectivity and can provide an economically viable synthesis process for this valuable chemical. While numerous, already existing chemical pathways of HBL synthesis are attempted to be used as little as possible because most of them have defects such as expensive or dangerous reactants, intense process conditions, and low utilization and selectivity, which causes the product extraction process to increase. In this work, a panel of 24 nitrilases was evaluated. During the study, the same initial conditions were used, the concentration of the substrate (KHB) and the mass concentration of nitrilase, while the reaction was monitored for 6 hours. The enzyme with the highest obtained product yield was chosen for the next step, i.e., kinetic research. Kinetic parameters of nitrilase catalyzed synthesis (R)-4-chlorine-3-hydroxybutanic acid from (R)-4-chlorine-3-hydroxybutironitrile were determined, from which the mathematical model was developed. It consists of a kinetic model and a balance of substances in the reactor. It was found that the enzyme has a low affinity for the substrate and that the reaction accompanies Michaelis-Menten's kinetics and the inhibition effect of the substrate and the product. The model was successfully validated by the implementation of the reaction in six different batch reactors with different initial conditions in the reactor. Samples of the reaction mixture were analyzed on a high-efficiency liquid chromatograph and a gas chromatograph. From these experiments, the deactivation constant was evaluated and it was concluded that the initial conditions in the reactor affect the stability of the enzyme