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Abstract: The purpose of this master's thesis was to determine the ability of certain organisms of the kingdom Fungi to produce a series of enzymes in their active form by solid-state fermentation. In this study, two types of fungi were used, Pleurotus ostreatus and Ganoderma lucidum. For this purpose, different growth media, cultivation times (8 and 10 days), extraction procedures (shaking and homogenization) and extraction medium (distilled water, sodium citrate buffer and sodium phosphate buffer) were used. First, for P. ostreatus mushroom, the optimization of the extraction procedure and time for isolation of enzymes in their active form (α-amylase, glucoamylase, cellulase, laccase, and protease) was studied. It was observed that the highest total protein concentration in mycelium extract was obtained by 8 min of homogenization (0.8607 mg/mL, and distilled water). Using the shaking procedure, the highest enzyme activities were achieved for α-amylase (24 h, 8.0413 U/mL, and sodium citrate buffer) and protease (3 h, 0.0040 U/mL, and sodium citrate buffer). With the homogenization process, the highest activities were achieved for the enzymes glucoamylase (10 min, 6.7113 U/mL, and sodium citrate buffer) and laccase (8 min, 12.2500 U/mL, and sodium citate buffer). For the mushroom G. lucidum, the growth medium and the extraction procedure were optimized, using the same extraction medium (sodium citrate buffer). In this case, α-amylase, glucoamylase, cellulase, laccase, protease, catalase, peroxidase, superoxidase dismutase (SOD), and lipase were studied. It was observed that the highest total protein concentration was obtained with 4 min of homogenization (0.0338 mg/mL). Furthermore, using the homogenization process, the highest activities were achieved for α-amylase (4 min, 16.3459 U/mL) and SOD (4 min, 9.2615 U/mL). With the shaking procedure, the highest activities were achieved for cellulase (3 h, 1.6332 U/mL), lipase (3 h, 16.924 U/mL), glucoamylase (3 h, 14.6737 U/mL), peroxidase (3 h, 0.0156 U/mL), protease (3 h, 0.0080 U/mL) and laccase (24 h, 20.7083 U/mL).
Keywords: medicinal mushrooms, Pleurotus ostreatus, Ganoderma lucidum, total proteins, enzymes activities.
Published in DKUM: 06.07.2022; Views: 367; Downloads: 26
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Abstract: Fatty ester synthesis with immobilized 1,3-specific lipase from Mucor Miehei is described. 1,2-Isopropylidene glycerol was peoduced by condensation of glycerol with acetone was esterified with oleic acid in the presence of a Mucor Miehei lipaze (Lipozyme TM) to obtain 1,2 isopropylidene- 3-oleoyl glycerol. The effects of various process parameters (temperature and pressure)and various ratios (enzyme/substrate) have been investigated to determine optimal conditions for the esterification process. The highest conversion of oleic acid (80% w/w) was obtained at 55 oC and 57.057 bar, while the optimal addition of lipase to substrate was determined to be 0,096 g per gram of reaction mixture. The esterification can be modelled successfully as a reverse second order reaction. Thermodynamic properties of the reaction system at 55 oC and 0.057 bar were also determined. Activation energy was 20.82 kJ/mole, entropy of activation -0,26 kJ/(Kmole) and free energy of activation was 103.32 kJ/mole.
Keywords: chemical engineering, biotechnology, esterification, syntheses, esters, enzymes, lipase, Mucor miehei, reaction kinetics, reaction thermodynamics, 1, 2-isopropylidene-3-oleoyl glycerol
Published in DKUM: 06.06.2012; Views: 2062; Downloads: 91
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Abstract: Ischnoderma resinosum produced extracellular ligninolytic enzymes laccase and MnP. The activity of laccase achieved the maximum on day 10 (29.4 U L-1), the MnP on day 14 (34.5 U L-1). Laccase and Mn-peroxidase were purified from the culture liquid using gel permeation and ion-exchange chromatographies. Purified Mn-peroxidase performed decolorization of all textile dyes tested (Reactive Black 5, Reactive Blue 19, Reactive Red 22 and Reactive Yellow 15). Laccase was inactive with Reactive Black 5 and Reactive Red 22, while all dyes were decolorized after addition of the redox mediators violuric acid (VA) and hydroxybenzotriazole (HBT). The culture liquid from I. resinosum cultures was also able to decolorize all dyes as well as the synthetic dyebaths in the presence of VA and HBT. The highest decolorization rates were detected in acidic pH (3-4).
Keywords: Ischnoderma resinosum, Basidiomycetes, Laccase, Mn-peroxidase, Textile dyes, ligninolytic enzymes
Published in DKUM: 01.06.2012; Views: 1574; Downloads: 84
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Abstract: A novel protease produced by Bacillus cereus grown on wool as carbon and nitrogen source was purified. B. cereus protease is a neutral metalloprotease with a molecular mass of 45.6 kDa. The optimum activity was at 45 °C and pH 7.0. The substrate specificity was assessed using oxidized insulin B-chain and synthetic peptide substrates. The cleavage of the insulin B-chain was determined to be Asn3, Leu6, His10-Leu11, Ala14, Glu21, after 12 h incubation. Among the peptide substrates, the enzyme did not exhibit activity towards ester substrates; with p-nitroanilide, the kinetic data indicate that aliphatic and aromatic amino acids were the preferred residues at the P1 position. For furylacryloyl peptides substrates, which are typical substrates for thermolysin, the enzyme exhibited high hydrolytic activity with a Km values of 0.858 and 2.363 mM for N-(3-[2-Furyl]acryloyl)-Ala-Phe amide and N-(3-[2-Furyl]acryloyl)-Gly-Leu amide, respectively. The purified protease hydrolysed proteins substrates such as azocasein, azocoll, keratin azure and wool.
Keywords: textile finishing, enzymatic modification, wool fibre, enzymes, Bacilus cereus, specificity, kinetics, metalloprotease
Published in DKUM: 01.06.2012; Views: 1933; Downloads: 98
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