Proteolytic Bacillus sp. Isolation and Identification from Tannery Alkaline Baths.

Area of Science:

• Biotechnology
• Enzyme Technology
• Industrial Microbiology

Background:

• Microbial alkaline proteases are crucial for sustainable industrial processes, offering alternatives to harsh chemicals.
• Reducing chemical usage and effluent treatment costs are key drivers for adopting eco-friendly enzymatic solutions.
• The Portuguese tannery agroindustry is a potential source for novel, industrially relevant microbial proteases.

Purpose of the Study:

• To isolate and identify novel alkaline protease-producing microbial strains from tannery agroindustry waste.
• To characterize the proteolytic activity and industrial applicability of the isolated strains.
• To evaluate the potential of these microbial proteases in various agroindustrial applications.

Main Methods:

• Isolation of microbial strains from alkaline tannery baths.
• Submerged cultivation and measurement of proteolytic activity.
• Identification using API biochemical tests, molecular biology, and GC-FAME analysis.
• Characterization of enzyme properties and growth kinetics.

Main Results:

• Two potent protease-producing strains were identified as *Bacillus subtilis* (CCMI 1253 and CCMI 1254).
• *B. subtilis* CCMI 1253 showed high proteolytic activity (0.70 ± 0.01 U mL^-1) and a growth rate of 0.88 ± 0.10 h^-1.
• The produced proteases demonstrated extracellular activity and adaptability to industrial conditions.

Conclusions:

• *Bacillus subtilis* strains CCMI 1253 and CCMI 1254 are promising sources of alkaline proteases for industrial applications.
• These microbial proteases can be utilized in leather processing, detergents, and waste treatment, aligning with green chemistry principles.
• The study highlights the potential of microbial proteases in advancing the bioeconomy and sustainable industrial practices.