Molecular and functional characterization of protease from psychrotrophic Bacillus sp. HM49 in North-western Himalaya

In this work, a psychrotrophic bacteria producing cold-active protease, was obtained from Dachigam National Park, an ecologically significant habitat in Western Himalayas owing to its varied endemic and endangered flora and fauna. This isolate was identified as Bacillus sp. HM49 via phenotypic, Gram staining, bio-chemical and 16S rRNA gene identification. Isolate HM49 when tested for proteolytic activity revealed prominent hydrolytic zone with the most production at 20 °C and pH, 8.0 post 72 h incubation. This enzyme was purified, enhancing its specific activity to 61.15 U/mg and its characterization studies revealed it to be a cold-alkaline protease being active in a wide pH (6.0-12) and temperature (5-40 °C) range. Amplification of CAASPR gene of HM49 was performed, followed by enzyme-substrate docking studies and MMGBSA providing details about its type, molecular weight validation as well as functional applications. The purified protease of HM49 was tested for laundry applications and the enzyme was found to be compatible with majority of the detergents tested. Its potential as an eco-friendly detergent additive was further validated by wash performance test as it effectively removed recalcitrant blood stains at a low temperature of 20 °C that could be beneficial for fine garments like silk which preferably need cold washing.