13.BACTERIAL DIVERSITYOF INDUSTRIALLY IMPORTANT HYDROLASES PRODUCERFROM LONAR LAKE, INDIA BY P. R.DUDHAGARA AND S.A. BHATT

Abstract

Lonar lake is very important habitat for extremophiles comprising the diverse groups of bacteria and archaea. Enzymes from such microorganisms are endured and carry out reactions efficiently under the multiple extreme conditions including high pH and salinity. The main aim of the study was to isolate and study the diversity of commercially valuable hydrolases producing bacteria. Using enrichment method total 18 isolates were isolated on starch, gelatin and tributyrin media for the screening of amylase, protease and lipase enzymes respectively. Among them, 7 isolates were recorded to produce two enzymes. After characterization of selected isolates, the identification was carried out using 16S rRNA gene decoding. All were either moderately halophilic or haloalkaliphilic group of bacteria showing salt requirement in the range of 2 to 5 % w/v with 8 to 9.5 pH. Selected 11 identified isolates belonged to Pseudomonadaceae, Vibrionaceae, Bacillaceae and Halomonadaceae families. Most of all the hydrolases were optimally active at pH 8.0 or above with 1 to 4 % salt concentration. Amylases of Halolactibacillus xiariensis and Halomonas mongoliensis were optimally active at 50 °C temperature whereas remaining amylases and proteases was found to be active at 40 to 45 °C temperature. Solvent stability against 25% Butanol, Benzene, Ethanol, Hexane, Methanol, Toluene and Xylene was very remarkable. Results suggest the impending application of the cultural diversity of the Lonar lake in enzyme biotechnology.

KEY WORD: Lonar lake, Hydrolases, Diversity.