Research Article
Rajasundari Kandaiah and Murug
Abstract
The distillery yeast biomass (DYB), a waste by-product from distilleries is one of the under-utilized protein sources to be exploited for the production of protein hydrolysates. In this study, a neutral protease produced from Bacillus megaterium PB4 isolated from agro wastes enriched soil exhibited significant deproteinization of distillery yeast biomass to yield protein hydrolysates. Among three protease producing strains isolated, the maximum protease production of 120.3 ± 1.4 U mL-1 was exhibited by PB4 grown in Luria-Bertani (LB) broth supplemented with casein at pH 7.0 and 30°C. The minimal media supplemented with various carbon and nitrogen sources, glucose and peptone significantly improved the protease production in PB4. The effect of metal ions such as Zn2+, Mg2+, Mn2+, Cu2+ at 0.5 and 1.0 mM final concentration in the media on protease production indicated that Zn2+ (1.0 mM) was favorable in enhancing the protease production. The Km and Vmax of PB4 protease for casein substrate was 0.6 U ml-1 and 217.3 μM min-1 mg-1 protein, respectively. The deproteinization rate for distillery yeast biomass was 84 and 76.4% using culture and crude enzyme extracted from PB4, respectively. To the best of our knowledge, deproteinization of distillery yeast biomass using proteolytic bacterial isolate has never been demonstrated before. The experimental results in the present study suggest that Bacillus megaterium PB4, can be utilized for the eco-friendly, economical production of protein hydrolysates and may be considered as a potential candidate in various biotechnological applications.