Isolation and Characterization of Amylase Inhibitor from Alkalophilic Bacteria Isolated from Lonar Crater and its Insecticidal Protein Producing Ability

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Five different isolates of alkalophilic bacteria were obtained from water and sludge sample of Lonar lake, in Buldhana district of Maharashtra. These isolates were identified as Cholesterol oxidase, Protease inhibitor, Amylase inhibitor. Alkaline Protease, Chitinase by 16S rDNA sequencing.In this paper, the characters of protease inhibitor produced by the five most potent isolates were studied for its insecticidal potential. Among five isolates, three isolates (isolate A, B, E) amylase inhibitor producing ability. Out of that isolate A i.e Bacillus thuringiensis serovar finitimus showed the highest (0.031 Unit mg protein-1) amylase inhibitory activity. The activity of Amylase inhibitor was almost constant over the range of pH. The optimum pH for the amylase inhibitor obtained from all the isolates was found to be pH 9. Specific activity of amylase inhibitor decreases at extreme pH (pH 12). The proteins showed stability upto 1hr when incubated on pH 9 to pH 11.The stability of enzyme decreases at extreme pH 12. AI isolated for all the alkalophile isolates were optimally active at 40°C and specific activity decreases at extreme temperature range 60°C. The thermal stability revealed that the enzyme was stable on 30°C to 40°C for upto 150 min. However, the enzyme activity declined drastically at temperature higher than 50°C.

Amylase inhibitor; lkalophilic bacteria; Lonar Crater