ISOLATION AND SCREENING OF HALOALKALINE PROTEASE PRODUCING BACTERIA FROM TANNERY SOLID WASTE

Abstract

Twenty bacterial strains were isolated on selective milk agar plates (pH 9.0) from tannery solid waste on the basis of different colony morphology. These strains exhibited variable haloalkaline protease activity and were tolerant to different concentration of both chromate (350-1450 μg/ml) and NaCl (2-9%). Those having clearance zone greater than 20.0 mm were considered as significant isolate. Out of twenty, nine strains were interestingly tolerant to high concentration of Cr(VI) (850-1450 mg/l) and NaCl (6.5-9%) and exhibited vibrant clear zone diameter between 21-35 mm. All these isolates in this study were capable of reducing Cr(VI) aerobically and the reduction values ranged between 50.0-76.0% after 16-20 h of growth. Further, significant haloalkaline protease production was observed in these bacteria within 24 h under wide temperature (25-45°C) and pH (8.0-10.5) range. The potential of these strains to produce protease at higher rate in the presence of wheat bran as a cheap carbon source and yeast extract or beef extract as a nitrogen source makes them a potential candidate for industrial applications and removal of Cr(VI) and proteinaceous waste simultaneously from industrial waste of alkaline nature.