Alkaline Mannanase Production from Bacillus subtilis Strain C3 in Complex Medium Containing Coconut Pulp

摘要

A strain of Bacillus subtilis, conveniently called strain C3, was isolated from grass litter. The optimum conditions for its growth and mannanase production were at 35°C to 37°C and at pH 8.0. Its alikalophilic property was interesting since it would be suitable for any biobleaching processes. The enzyme was found to be highly active against glucomannan, which, in turn, could efficiently induce the mannanase production from C3. The medium, named "CPM", was composing of 0.3% (w/v) of NH4NO_3, 0.2% (w/v) of MgS0_4.7H_2 O, 0.01% (w/v) of FeS0_4.7H_2O, 0.05% (w/v) of CaCl_2.2H_2O, 7.54% (w/v) of K_2HP0_4, 2.32% (w/v) of KH_2P0_4 and 2% of coconut pulp. C3 required high aeration for mannanase production. At the lab-scale of 200 rpm rotatory shaking-flask culture, the ratio of at least 2:10 unit volume of medium to flask were required to reach the maximum mannanase activity units. C3 mannanase obtained was highly stable at 40°C and 50°C. C3 mannanase produced from CPM medium under optimum condition could effectively release out around 5.5 mg of reducing sugar from each gram of coconut pulp.