Stability and activity of the partially purified spray-dried protease from bacillus sp. smia-2 and its characterization as a laundry detergent additive

Enzymes, and particularly proteases, have become an important and indispensable part of industrial processes such as laundry detergents and food products. In this study, after production by Bacillus sp SMIA-2 in the complex medium and separation of solids from the fermentation broth, protease was dried and some biochemical properties of the enzyme after rehydration was investigated for the purposes of exploiting its potential as detergent additive. Studies on the enzyme characterization revealed that the optimum temperature of protease was 70oC. The enzyme retained about 55% of its maximum activity after 10 min incubation at 70oC. The optimum pH of the enzyme was found to be 8.5. After incubation of the enzyme solution for 2h at 25oC at pH 10.0, the activity was reduced to 53% of its maximum activity. Activity of the enzyme was stimulated in the presence of Ca2+. The spray-dried protease retained more than 90% activity after incubation for 30 min at 40oC with 0.25% (w/v) SDS and RENEX-95 and more than 60% when incubated with 0.25 and 0.5% TRITON x-100, H2O2 and RENEX-60. The stability of protease was good as the enzyme retained 64% of its activity after 30 minutes incubation at 40oC in the presence of the detergent Campeiro®. The enzyme improved the washing performance of a detergent for removing stains from uniformly soiled clothes with cocoa, milk and sugar (EMPA 112).