Cow dung as a novel, inexpensive substrate for the production of a halo-tolerant alkaline protease by Halomonas sp PV1 for eco-friendly applications

The production of a halo-tolerant-alkaline protease by Halomonas sp. PV1 under solid state fermentation was optimized. Among the substrates evaluated, cow dung supported the maximum protease production (1351 U/g) when compared with wheat bran (1013 U/g). Process parameters such as, the fermentation period (72 h), pH (8.0), initial moisture (140%, v/w) and the inoculum level (15%, v/w) were optimized. The optimum enzyme production was achieved with 1.5% (w/w) xylose and a 1.25% (w/w) yeast extract. The partially purified protease enzyme was active over a temperature range of 30-50 degrees C and a pH range of 7-10. The protease was remarkably stable on sodium dodecyl sulfate and on various commercial detergents. The enzyme effectively dehaired goat hides, and makes it a potential source of alkaline protease. This substrate may have wide spread applications in enzyme bioprocesses like wheat bran. (C) 2012 Elsevier B.V. All rights reserved.