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A strain of Brevibacillus formosus, capable of producing a high level of chitinase, was isolated and characterized for the first time from the Great Indian Desert soils. The production of extracellularly secreted chitinase was analyzed for its biocontrol potential and optimized by varying media pH, temperature, incubation period, substrate concentrations, carbon and nitrogen sources, etc. A twofold increase in chitinase production (798 IU/mL) was achieved in optimized media containing (g l(-1)) chitin 2.0, malt extract 1.5, glycerol 1.0, ammonium nitrate 0.3%, T-20 (0.1%) and media pH 7.0 at 37 °C. The produced enzyme was purified using a three-step purification procedure involving ultra-filtration, ammonium sulphate precipitation and adsorption chromatography. The estimated molecular weight of the purified enzyme was 37.6 kDa. The enzyme was found thermostable at higher temperatures and showed a t ½ of more than 5 h at 100 °C. Our results show that the chitinase produced by B. formosus BISR-1 is thermostable at higher temperatures.

The biotransformation of acrylonitrile was investigated using thermophilic nitrilase produced from a new isolate Streptomyces sp. MTCC 7546 in both the free and immobilized state. Under optimal conditions,the enzyme converts nitriles to acids without the formation of amides.The whole cells of the isolate were immobilized in agar-agar and the beads so formed were evaluated for 25 cycles at 50 degrees C. The enzyme showed a little loss of activity during reuse. Seventy-one per cent of 0.5 M acrylonitrile was converted to acid at 6 h of incubation at a very low density of immobilized cells, while 100% conversion was observed at 3 h by free cells.

The efficiency of xylanase of Bacillus brevis BISR-062 as a prebleaching agent was evaluated on three nonwoody pulps at two different pH values (7.0 and 8.5). Crude xylanase was found to have an optimum temperature and pH of 65-70 degrees C and 7.0, respectively. The stability of the enzyme was determined at two pH values (7.0 and 8.0), and it lost approx 50% of its activity at both values within 2 h at 50 degrees C. However, the enzyme was found to be effective as a prebleaching agent only with rice straw pulp. A maximum brightness gain of 6 points was obtained with this pulp at pH 7.0. The strength properties of the rice straw pulp at pH 7.0 also improved as the result of enzyme treatment.