Catalytic Role of Thermostable Metalloproteases from Bacillus subtilis KT004404 as Dehairing and Destaining Agent

Abstract

Proteases with characteristic stabilities are considered attractive candidates for industrial catalysis. In the present study, a potent bacterial strain KT004404, an inhabitant of hydrothermal vents, was isolated and characterized for protease production. Initial screening indicated that this strain produced a hydrolytic zone of 30 mm 16S rRNA-based identification revealed that our isolate was a strain of Bacillus subtilis. Optimum reaction condition for maximum protease production was determined as 55 °C, pH 6, 1 % inoculum size and malt extract as primary growth substrate supplemented with 1 % dextrose. Yield of the enzyme was increased up to 7.53 folds with a specific activity of 55.125 U/mg after gel filtration chromatography. SDS-PAGE analysis confirmed the size of protease as 28.24 kDa. Purified enzyme retained its catalytic activity over a broad range of temperature (5 to 65 °C) and pH [5-8]. Addition of metal ions shown to have a stimulatory effect on catalytic properties while EDTA inhibited the efficiency of the enzyme confirming it as a metalloprotease. Protease exhibited excellent stability and activity in the presence of anionic surfactants, solvents, and detergents. The results of dehairing and destaining experiments suggested that the protease produced by B. subtilis KT004404 could be used in leather and textile industries with ecological benefits.

Keywords: Bacillus subtilis; Dehairing; Destaining; Metalloproteases; Thermotolerance.