Biotechnological application of bacterial alkaline thermostable enzymes in bio-detergent industry

ABSTRACT

This is an investigation concerned on the production of alkaline thermostable microbial enzymes for application in biodetergent technology. Bacillus licheniformis- B42 and Geobacillus stearothermophilus -B78 were selected and identified among one hundred and fifty-three thermophilic bacterial isolates with respect to their ability to produce alpha-amylases, cellulases, proteases and lipases grown on some agro-industrial wastes at 55 degree C and at pH 9 for application in biodetergent technology. Productivity of four alkaline thermostable enzymes by both selected strains using slaughter house wastes [SHW] as best substrate for proteases and lipases and potato peel [PP] as best substrate for alpha-amylases and cellulases. The enzymatic level more affected by incubation temperature, pH, SHW and PP concentrations, inoculum size, incubation period, carbon, nitrogen, metal inducer and vitamins sources, under shaking conditions. Four alkaline thermostable enzymes were produced under all optimal nutritional and environmental conditions and purification by column chromatography on Sephadex G200 and G100, respectively were performed. Purification of four produced alkaline thermostable enzymes steps resulted in raising the purification fold to 17.04,15.24, 411.9 and 27.33 times in comparable with crude enzymes for alpha-amylase. cellulase, protease and lipase, respectively. The wash performing analysis of the four enzymes revealed that, it could effectively remove a variety of stains such as blood, apple, chocolate, mango, strawberry, salad and pomegranate by treatment at 55 degree C for 15 min when alkaliphilic-thermostable crude/purified enzymes were added separately or in combination with or without detergent [Rabso] as an Egyptian local detergent product. The crude enzymes of these two bacterial strains proved to be potentially candidates for the application in the detergent technology