Isolation, Screening, and Identification of Alkaline Protease-Producing Bacteria and Application of the Most Potent Enzyme from Bacillus sp. Mar64

In this study, thirty-seven alkaline protease-producing bacteria were recovered from different regions of Saudi Arabia. The proteolytic strain with the highest productivity was identified as Bacillus sp. Mar64. Maximum productivity of Mar64P alkaline protease was reached at 60 h, pH 9.0, and 45 & DEG;C using 1% tyrosine and 0.5% maltose as nitrogen and carbon supplies, respectively. Specific activity was intensified to 8.5-fold with a recovery of 12.4% and SDS-PAGE revealed one band at 28 kDa after enzyme purification. Mar64P was maximally active at 55 & DEG;C and pH 11.0 with thermal stability up to 70 & DEG;C and pH stability at 7.0-12.0 for 1 h. It was inhibited by EDTA and unaffected by PMSF, therefore tentatively classified as metalloprotease-type. Storage efficacy was effective for up to eight weeks and it was durable in presence of organic solvents (20%, v/v) such as acetonitrile, acetone, and isopropanol upto to 15 days. The enzyme was compatible with dry detergents at both low and high temperature, in addition, was successful in removing various stains such as blood, egg yolk, chocolate, tea, coffee, and sweat. Furthermore, it was successful in removing skin hairs and hydrolyzing gelatin of waste X-ray films. Collectively, due to these unique properties, Mar64P could be considered an environmentally friendly candidate in both detergent and leather industries.

Automated summary

In this study, alkaline protease-producing bacteria were isolated from different regions of Saudi Arabia, and Bacillus sp. Mar64 was identified as the strain with the highest productivity. The enzyme showed maximum productivity at 60 h, pH 9.0, and 45°C, using tyrosine and maltose as nitrogen and carbon sources, respectively. It exhibited specific activity, thermal stability, and pH stability, and was tentatively classified as a metalloprotease-type. The enzyme showed compatibility with organic solvents, effectiveness in removing stains and skin hairs, as well as hydrolyzing gelatin in waste X-ray films, making it a potential environmentally friendly candidate in detergent and leather industries.