Screening and assessment of cellulase from bacilli sp isolated from a Kenyan soda lake
Alkaline cellulases have wide spread industrial and commercial applications due to their stability at pH values higher than 9.5. They can be applied in place of chemicals during detergent formulation for cleaning and colour clarification in detergent industries as well as de-inking and fibre modification in pulp and paper industries (Kochavi et al., 1990; Tyndall, 1990). Another application would be in the replacement of pumice stone and harsh chemicals in bio stoning process in textile industries. These cellulases can be extracted from alkaliphilic bacteria i.e. bacteria growing in alkaline/basic habitats. Use of alkaline cellulases is especially attractive in industrial applications as they are able to withstand the harsh conditions associated with such processes. In this study, 5 Bacillus sp designated Bacillus sp LBW 213, Bacillus sp LBW 2 7 19, Bacillus sp LBW 35 Bacillus sp LBW 33 and Bacillus sp 313 previously obtained from Lake Bogoria water samples were used as a source of alkaline cellulases. The isolates were screened for cellulase production on CMC agar plates at pH 10.4 and 37ºC using the Congo red clearing zone assay. All five were found to be excellent cellulase producers with a halo size of approximately 2.5. Due to this remarkable outcome, all the Bacilli sp were then assessed for production of Endoglucanase and Fpase. Both endoglucanase and Fpase activities of the cells were followed for a period of 36 hours, with cultivation carried out at 37oC in liquid broth. Endoglucanase activities were observed in the range of 0 - 0.106 U/ml with maximum production recorded after 4 h and subsequent decrease in activity for all the bacteria, reaching undetectable levels after 36 h. Fpase activities were observed within a range of 0 - 0.009 U/ml with maximum production after 4 hours and decline in activity throughout the remaining 36 hour incubation. Low enzyme production was attributed to un-optimized culture conditions.