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Microbial Transglutaminase: Purification, Characterisation and Bioactive properties.

Mabel, M. J. (2012) Microbial Transglutaminase: Purification, Characterisation and Bioactive properties. PhD thesis, University of Mysore.

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Abstract

Transglutaminase (TG; protein-glutamine γ-glutamyl transferase EC 2.3.2.13) is an enzyme which can modify proteins by amine incorporation, cross-linking and deamidation. The enzyme is of interest to food industries, because of its capability to modify the functional properties of proteins. The cross-linking property of TG useful in improving nutritional properties of foods by incorporating essential amino acids like lysine to proteins and the possibility of improving the functional properties of foods by TG treatment is promising. In view of the tremendous market potential for TG, there exists enough scope for screening new sources of the enzyme which in turn is a promising step towards the development of novel protein foods. Screening and selection of bacterial, fungal and actinomycete species for microbial transglutaminase production under submerged fermentation conditions was carried out. Streptomyces griseocarneus MTCC 328 was found to produce the enzyme at about 0.09 U/ml. The enzyme exhibited calcium independent activity and was extracellular in nature. The optimization of media for the enzyme production using statistically based experimental designs resulted in an enhanced enzyme activity of 0.32 U/ml. The enzyme was purified by ammonium sulphate precipitation, followed by successive chromatographies on CM-cellulose and Sephadex G-75 columns with a 34 fold purification and specific activity of 1.5 U/mg proteins. The purified enzyme was found to have optimum activity at 37 - 45 0C and in a range of pH 6.0-7.0. The activity of the purified enzyme was inhibited by Cu2+, Zn2+, Hg2+, Co2+ and NEM (N-ethyl maleimide), which suggests the presence of a thiol group in the MTG’s active site. The bioactive property of the purified enzyme was confirmed by cross-linking 11S protein fractions of soybean. The effect of purified enzyme in improving the quality attributes of transglutaminase mediated fructooligosaccharides, a low calorie prebiotic enriched yoghurt was studied with respect to physicochemical properties such pH, syneresis or whey separation, and sensory attributes like colour, texture etc during 15 days of storage. Transglutaminase from the novel source isolated in this study was found to be potent in improving the physicochemical properties of fructooligosaccharides enriched yoghurt.

Item Type: Thesis (PhD)
Uncontrolled Keywords: microbial transglutaminase production, food industries, submerged fermentation
Subjects: 600 Technology > 08 Food technology > 16 Nutritive value > 05 Enzymes
Divisions: Fermentation Technology and Bioengineering
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 14 Nov 2013 06:39
Last Modified: 21 Dec 2016 12:55
URI: http://ir.cftri.com/id/eprint/11292

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