A deep-sea hydrogen peroxide-stable alkaline serine protease from Aspergillus flavus.

Abstract

We report here the production of an alkaline serine protease by Aspergillus flavus isolated at 5600-m depth from deep-sea sediments of the Central Indian Basin. When grown on defatted groundnut oil meal at 30°C for 48-72h, this fungal isolate produced 2000-2500 ACU mL-1 of alkaline protease. The purified protease had activity optima at pH 10.0 and 45°C. It was a thiol-independent serine protease, identified as an alkaline serine protease ALP1 with a molecular mass of 42.57kDa. The thermostability and activity of the enzyme increased at 60°C, in the presence of additives such as sucrose, Tween 20, sorbitol, Ca2+ and glycerol and was not adversely affected by H2O2 indicating its potential as a detergent additive.