Production of moderately halotolerant, SDS stable alkaline protease from Bacillus cereus MTCC 6840 isolated from lake Nainital, Uttaranchal state, India

Abstract

A moderately cold active, extracellular alkaline protease producing bacterium was isolated from a fresh water lake. The isolate was found to be a gram-positive, rod shaped organism later identified as Bacillus cereus MTCC 6840. The bacterium produced the maximum amount of enzyme when allowed to grow for 24 h at temperature 25º and pH 9.0. Among a variety of substrates used, fructose as a carbon source and a combination of yeast extract and peptone as nitrogen source, supported the maximum protease production by the organism (120 U/ml). Fe ++ and Co ++ stimulated the enzyme activity whereas Ca ++ , Cu ++ , K + , Mg ++ and Mn ++ inhibited it to different extents. The protease was found to be highly stable in the presence of NaCl, SDS and acetone. Treatment with EDTA and PMSF resulted in the considerable loss of enzyme activity. The enzyme was found to be optimally active at pH 9.0 and temperature 20ºC.

Immobilization of Bacillus megaterium MTCC 2444 by Ca-alginate entrapment method for enhanced alkaline protease production

“…The treatment with SDS in the concentration range of 0.05 to 0.6 % retained the protease activity from B. megaterium MTCC 2444 in the range of 70 to 75 % (Fig.12). These results were similar to the activity of protease of B. cereus MTCC6840 at 1 % concentration of SDS (Joshi et al 2007). In contrast, VM10 protease showed 60 to 65 % activity towards 0.05 to 0.4 % SDS concentration (Venugopal and Saramma 2008).…”

“…2). Similar results were reported for the protease production by B. subtilis BS1 (Shaheen et al 2008), whereas the optimum pH of 9.0 and 10.5 were recorded for B. cereus MTCC6840 and B. circulans, respectively (Joshi et al 2007;Jaswal et al 2008). The optimum incubation time was 48 h (Fig.…”

Concomitant production of protease and lipase by Bacillus licheniformis VSG1: production, purification and characterization

“…Thus YE served to be a better nitrogen source for protease and lipase production than peptone. Joshi et al (9) have reported a combination of both YE and peptone as a better source for protease production by Bacillus cereus.…”

Extreme Environments: Goldmine of Industrially Valuable Alkali-stable Proteases

“…Heat stable protease production at 25 o C from a psychrotrophic P. fluorescens RO98 was reported by Koka and Weimer [97]. Joshi et al [86] reported maximum protease production at pH 9.0 and 25 o C from Bacillus cereus MTCC 6840 isolate. Kasana and Yadav [85] reported thermoalkalistable protease from a psychrotrophic Exiguobacterium sp.…”

“…The protease retained 78% activity even in the presence of 20% NaCl [180]. An alkaline protease of halotolerant B. cereus MTCC 6840 exhibited 100% stability in the presence of 5% NaCl [86], and showed good activity in the range of 6-10% (w/v) NaCl concentrations. An [180,181].…”