TRIBUTYRIN-ESTERASE BIOSYNTHESIS IN Geobacillus sp. AGP-04 A STUDY OF REGULATORY MECHANISM.

Abstract

Microbial esterases have a promising biotechnological potential to be used in various industrial purposes from the food industry to pharmaceutical industry. To accomplish  appropriate function and higher quantity of the biocatalysts there is a need to govern the specific control of the enzyme synthesis. This article reports the regulation of a trybutyrin-esterase synthesis in a thermophilic bacterium, Geobacillus sp. AGP-04. Tributyrin alone itself induced esterase synthesis. Other triglycerides, sugar-alcohol and other carbon sources exhibited little or no enzyme induction. Lower concentration (0.01–0.15% v/v) of the enzyme catalyzed end products, i.e. glycerol and butyric acid in the presence of tributyrin induced enzyme synthesis though higher concentration (>0.15%) was inhibitory. The addition of superfluous energy rich phosphonucleotides did not enhance the enzyme synthesis. Addition of glucose (about 0.2%) to the media supplemented with tributyrin repressed tributyrin-esterase biosynthesis. cAMP alleviated the enzyme synthesis in the glucose mediated repressed cell. Potent ionophores like 2-4-dinitrophenol and Carbonyl cyanide 3-chlorophenylhydrazone (CCCP) repressed enzyme synthesis by inhibiting ATP synthesis in the cell. The study revealed that tributyrin-esterase synthesis to be an energy dependent process and it is under the control of catabolic repression.