Author:
Georgiev Danail,Dobrev Georgi,Shilev Stefan
Abstract
Aim: To characterize the enzyme phytase produced by phytase-active Candida melibiosica 2491 for subsecuent use in feed industry. Methods: C. melibiosica 2491 had been selected among 118 strains as the most productive strain of phytase. In present study, the enzyme was first purified through electrophoresis grade in four steps: precipitation with organic solvent, ultrafiltration, gel chromatography and Denaturing gel electrophoresis (SDS–PAGE). Results: Higher levels of purification were obtained using ethanol. The gel chromatography showed an elution maximum at 11-12 fractions that characterize the corresponding one as high-molecular weight phytase. The purification level was found to be 19.5 folds with specific enzyme activity of 2.75 U/mg protein and yield – 19.64 %. Furthermore, the molecular weight of purified phytase was estimated to 35.9 кDa, with optimum of pH – at 4.5 and optimum of temperature at 55 °C. Maximum phytase activity in case of whole cells was found at 50 оС, which was less than using the purified enzyme. It was activated through 5 mM of Ba2+, 10 mM of Mn2+ and K+ ions. Total inhibition effect was achieved from Fe3+, Hg2+ and Zn2+. Copper ions (Cu2+) in concentrations at 5 mM conducted to partial inhibition effect, but at 10 mM the phytase activity was equal to zero. Low inhibition effect was determined in case of cobalt ions (Co2+) at concentrations of 10 mM. The phytase displayed broad substrate specificity and the Km for phytate was estimated to be 0.21 mM under the experimental conditions, while Vmax – 19.9 µМ/ml. Conclusion: Although the phytase produced by C. melibiosica 2491 is a promising enzyme to be used successfully in feed production, more investigations are needed to ensure its advantages.
Publisher
Faculty of Food and Agriculture, United Arab Emirates University
Subject
Agronomy and Crop Science,Animal Science and Zoology,Applied Microbiology and Biotechnology,Food Science
Cited by
4 articles.
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