Stable activity of extra-cellular xylanases and its phylogeny in different Bacillus species

Abstract

The production of cellulose free xylanase has increased its demand for waste treatment in pulping and bleaching industrial processes. Four Bacillus strains were selected on the basis of their habitation for the production of xylanase in xylan based nutrient culture. The secreted xylanase was referenced with protein marker for size of 20.3kDa in B. subtilis 168, 20.4kDa in B. pumilus, 28.6kDa B. cereus and 23.3kDa in B. amyloliquefaciens on SDS-PAGE. High activity of xylanase was observed in B. pumilus than B. amyloliquefaciens and B. cereus under harsh extremophillic culture conditions like as 28ºC with pH 4.0 and 50ºC with pH 10.0. The phylogenetic tree shows divergence of xylanase produce by B. pumilus from other 4 Bacillus species because of its evolution in proteins sequence for adaptation to severe habitate-conditions. In optimum culture medium, maximum cell biomass produced by B. pumilus (p ≤0.05) and significantly higher total extra-cellular protein contents in B. subtilis cultures. It might be permissibly nice, if origin of xylanases could be excised from B. pumilus and produced with B. subtilis 168 that could bring a revolution in pulp and paper industry. Preference for B. subtilis 168, it is being a safe bacterium for neighborhood.