A polylactic acid degrading lipase from Bacillus safensis: Characterization and structural analysis

Area of Science:

• Biochemistry
• Enzymology
• Microbiology

Background:

• Polylactic acid (PLA) is a biodegradable polymer with increasing applications.
• Efficient degradation methods for PLA are crucial for environmental sustainability.
• Enzymatic degradation offers a promising and eco-friendly approach.

Purpose of the Study:

• To identify and characterize a novel enzyme capable of degrading polylactic acid.
• To evaluate the enzyme's activity, stability, and optimal conditions for PLA degradation.
• To investigate the structural features and conservation of the identified enzyme.

Main Methods:

• Genome annotation and real-time quantitative PCR for enzyme identification and validation.
• Enzyme activity assays at various pH and temperature conditions.
• Analysis of hydrolysis products and surface changes on PLA films.
• Bioinformatic analysis of the enzyme's catalytic triad and conserved sequences.

Main Results:

• A polylactic acid-degrading triacylglycerol lipase (TGL) was identified from Bacillus safensis.
• TGL exhibits optimal activity at pH 9.0 and 55°C, with stability at pH 9.0 and 45°C.
• The enzyme erodes PLA films, increases hydrophilicity, and produces lactate monomer and dimer.
• TGL possesses a conserved catalytic triad (Ser77, Asp133, His156) and an Ala-X-Ser-X-Gly motif.

Conclusions:

• Bacillus safensis harbors a TGL with significant polylactic acid-degrading capabilities.
• The enzyme's optimal conditions and structural features suggest its potential for biotechnological applications in plastic waste management.
• The high conservation of TGL indicates its robust enzymatic function within the Bacillus genus.