Preparation of cross-linked tyrosinase aggregates

2008-02-01
Aytar, Burcu Selin
Bakir, Ufuk
Tyrosinase from mushroom was immobilized as a cross-linked enzyme aggregate (CLEA) via precipitation with ammonium sulfate and cross-linking with glutaraldehyde. The effects of precipitation and cross-linking on CLEA activity were investigated and the immobilized tyrosinase was characterized. Sixty percent ammonium sulfate saturation and 2% glutaraldehyde were used; a 3-h cross-linking reaction at room temperature, at pH 7.0 was performed; particle sizes of the aggregates were reduced; consequently, 100% activity recovery was achieved in CLEAs with enhanced thermal and storage stabilities. Slight changes in optimum pH and temperature values of the enzyme were recorded after immobilization. Although immobilization did not affect V-max, substrate affinity of the enzyme increased. Highly stable CLEAs were also prepared from crude mushroom tyrosinase with 100% activity recovery.
PROCESS BIOCHEMISTRY

Suggestions

Degradation of chlorinated compounds by Penicillium camemberti in batch and up-flow column reactors
Taseli, BK; Gökçay, Celal Ferdi (Elsevier BV, 2005-02-01)
A Penicillium camemberti strain isolated in this laboratory was studied for its ability to degrade chlorinated compounds including pentachlorophenol (PCP), 2-chlorophenol and trichloroacetic acid. The batch experiments were conducted in shake flasks using PCP as co-substrate resulting in around 56% PCP removal by the fungus. Experiments in shake flasks not containing acetate but Tween 80, produced 86% of PCP and 53% of 2-chlorophenol removals in 21 days. PCP was also fed to a column reactor with an adsorbab...
Substrate interactions during the biodegradation of benzene, toluene and phenol mixtures
Abu Hamed, T; Bayraktar, E; Mehmetoglu, T; Mehmetoglu, U (Elsevier BV, 2003-09-30)
Benzene, toluene and phenol were degraded completely at high initial concentrations by Pseudomonas putida F I ATCC 700007. Two hundred and fifty milligram per litre benzene, 225 mg/l toluene and 200 mg/l phenol were degraded individually in 19, 14 and 3 5 h, respectively. The biodegradation times increased on increasing the substrate concentration. The maximum biodegradation rates were 149 mg benzene/g dry cell h for 60 mg/l benzene, 44 mg toluene/g dry cell h for 110 mg/l toluene and 102 mg phenol/g dry ce...
SURVIVAL KINETICS OF LACTIC-ACID STARTER CULTURES DURING AND AFTER FREEZE-DRYING
BOZOGLU, F; OZILGEN, M; BAKIR, U (Elsevier BV, 1987-09-01)
Survival kinetics of lactic acid starter cultures were modeled considering the microorganism and external medium interfacial area as the critical factors determining the resistance of the microorganisms to freeze-drying. Surviving fraction of the microorganisms increased with the increasing biomass concentration during freeze-drying, and this is attributed to the mutual shielding effect of the microorganisms against the severe conditions of the external medium. Survival of the microorganisms over the storag...
Bacilysin biosynthesis by a partially-purified enzyme fraction from Bacillus subtilis
Yazgan, A; Özcengiz, Gülay; Ozcengiz, E; Kilinc, K; Marahiel, MA; Alaeddinoglu, NG (Elsevier BV, 2001-10-04)
Biosynthesis of dipeptide antibiotic bacilysin by a partially purified enzyme prepared from Bacillus subtilis PY79 was studied. Cell material was desintegrated by treatment with lysozyme and sonication and the extract was subjected to ammonium sulfate fractionation. Bacilysin-synthesizing enzyme activity was precipitated between 40% to 70% ammonium sulfate saturation. In vitro enzymatical synthesis of bacilysin was confirmed by performing thin layer chromatographic comparison of the antibiotic formed with t...
Production of L-aspartic acid by biotransformation and recovery using reverse micelle and gas hydrate methods
Aydogan, Oezlem; Bayraktar, Emine; Parlaktuna, Mahmut; Mehmetoglu, Tanju; Mehmetoglu, Uelkue (Informa UK Limited, 2007-01-01)
L-Aspartic acid (L-Asp) was produced using Escherichia coli (ATCC 11303), and its recovery from the reaction mixture was studied using reverse micelle and gas hydrate methods. The effect of initial substrate concentration on L-Asp production was also investigated, and inhibition was shown to occur above 0.75 mol L-1. The values of the kinetic constants were determined as r(max) = 2.33 x 10(-4) mol L-1 min(-1), K-M = 0.19 mol L-1, and K-ss = 3.98 mol L-1. The reverse micelle phase used for extraction contain...
Citation Formats
B. S. Aytar and U. Bakir, “Preparation of cross-linked tyrosinase aggregates,” PROCESS BIOCHEMISTRY, pp. 125–131, 2008, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/65002.