Preparation of cross-linkedtyrosinase aggregates

Download

index.pdf

Date

2006

Author

Aytar, Burcu Selin

Metadata

Show full item record

Item Usage Stats

209
views

421
downloads

The aim of this study was to prepare cross-linked enzyme aggregate (CLEA) from crude mushroom (Agaricus bisporus) extract. However, the optimization of CLEA production was performed by using pure tyrosinase. Important parameters were determined as protein, ammonium sulfate and glutaraldehyde concentrations, CLEA particle size, and cross-linking temperature and period. On the other hand, the order of ammonium sulfate and glutaraldehyde addition did not affect the yield of CLEA. Optimum CLEA preparation conditions were 60 % ammonium sulfate saturation, 2 % (v/v) glutaraldehyde, and 3 hour cross-linking reaction at room temperature. Particle size of the CLEAs should be reduced by mechanical stirring to eliminate mass transfer limitations. Under these circumstances, 100 % recovery was obtained from both pure and crude tyrosinases. Optimum temperature and the activation energy for catechol oxidation were determined as 34 oC and 16.9 kcal/mol for CLEAs, whereas, 32 oC and 12.5 kcal/mol for the free enzyme. Furthermore, the thermostability of CLEAs was significantly higher than the free enzyme. CLEAs, prepared from crude mushroom extract, retained 72 % of its maximum activity in eight months storage at 4 oC. Moreover, changing the storage temperature from 4 oC to room temperature did not decrease CLEAs stabilities.

Subject Keywords

Research.

URI

http://etd.lib.metu.edu.tr/upload/2/12607318/index.pdf
https://hdl.handle.net/11511/16250

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Inhibitory effects of plant originated extracts on bovine lens aldose reductase Zaimoğlu, Selin; Çoruh, Nursen; Department of Biotechnology (2004) Aldose reductase, E.C.1.1.1.21, catalyzes the reduction of different types of aldehydes to their corresponding alcohols, and especially reduces various aldo-sugars using NADPH as the coenzyme. Under hyperglycemic conditions aldose reductase is involved in the development of diabetic complications. As a result, interest has been placed over the years on the development of potent aldose reductase inhibitors for possible use in the therapy of these severe diabetic complications. In this study, aldose reductase...
Removing algae from stabilization pond effluents by using trickling filters Kaya, Devrim; Dilek, Filiz Bengü; Department of Environmental Engineering (2005) The objective of this study is to remove turbidity originating from algae present in oxidation ponds effluents by an easy and inexpensive method. For this reason, a novel lab-scale Step Feed Dual Treatment (SFDT) process was constructed and the efficiency of trickling filter (TF) to remove algae and organic matter was investigated. SFDT process developed in this study is the unique, inexpensive and new system to scavenge algae from oxidation pond effluents. In this system, influent is first treated in a sta...
Degradation of decabromodiphenyl ether (BDE-209) in microcosms mimicking sediment environment subjected to comparative bioremediation strategies Demirtepe, Hale; İmamoğlu, İpek (Elsevier BV, 2019-03-01) The aim of this study was to examine bioremediation strategies for BDE-209 contaminated sediments. Sediment microcosms were established to observe anaerobic debromination of BDE-209 under conditions representing three bioremediadon strategies: biostimulation, bioaugmentation and natural attenuation. To simulate biostimulation, a defined mineral medium containing both a carbon source (sodium formate) and electron donor (ethanol) was added into sediments. Bioaugmentation was established by enrichment of the s...
Optimising clarification of carrot juice by bacterial crude pectinase Uzuner, Sibel; Çekmecelioğlu, Deniz (2015-12-01) This study was undertaken to search for potential use of crude bacterial pectinase enzyme produced from Bacillus subtilis grown on hazelnut shell hydrolysate in clarification of carrot juice and to optimize the enzyme load, pH and time using the Box-Behnken response surface methodology (RSM). The carrot juice was treated with the crude pectinase enzyme (5.60 U mL(-1)) at different concentrations (0.1-0.5%), pH (4-7), and time (2-6 h). The obtained enzyme was also compared with commercial fungal pectinase at...
Preparation and investigation of poly(methylmethacrylate) nano-capsules containing haloxyfop-R-methyl and their release behavior Mahmoudian, Mehdi; Torbati, Samaneh; AliMirzayi, Neda; Nozad, Ehsan; Kochameshki, Mahmoud Ghasemi; Shokri, Aref (Informa UK Limited, 2019-12-06) In this study, the preparation and characterization of haloxyfop-R-methyl herbicide loaded in poly(methylmethacrylate) (PMMA) nano-capsules by emulsion polymerization and its release behavior were investigated. The chemical characterizations of PMMA/haloxyfop-R-methyl nano-capsules were confirmed by FT-IR spectroscopy method, and the surface morphology was studied by field emission scanning electron microscopy and transmission electron microscopy. Also, the herbicide loading and encapsulation efficiency wer...

Citation Formats

B. S. Aytar, “Preparation of cross-linkedtyrosinase aggregates,” M.S. - Master of Science, Middle East Technical University, 2006.