Engineering Bacillus megaterium Strains To Secrete Cellulases for Synergistic Cellulose Degradation in a Microbial...

Area of Science:

• Biotechnology
• Synthetic Biology
• Microbial Engineering

Background:

• Growing environmental concerns necessitate efficient waste biomass utilization for microbial chemical production.
• Current biomass processing involves costly enzymatic purification steps for cellulases.

Purpose of the Study:

• To engineer a synthetic microbial community using specialized Bacillus megaterium strains for synergistic cellulose degradation.
• To identify and optimize signal peptides for efficient cellulase secretion.

Main Methods:

• Targeted secretion of endoglucanase (EGI1) and a multimodular cellulase (Cel9AT) from B. megaterium.
• Screening a library of signal peptides (SPs) to tag cellulases for secretion.
• Bioassays to confirm cellulase activity and identify optimal SP constructs (LipA SP for EGI1, YngK SP for Cel9AT).
• Characterization of individual and cocultured strains for synergistic cellulolytic activity.

Main Results:

• Optimized strains successfully secreted EGI1 and Cel9AT using selected signal peptides.
• The combination of EGI1 and Cel9AT exhibited higher cellulase activity than individual enzymes.
• Cocultures of the engineered B. megaterium strains demonstrated synergistic degradation of cellulose, outperforming monocultures.

Conclusions:

• A synthetic microbial community approach with specialized B. megaterium strains enables synergistic cellulose degradation.
• This engineered system offers a cost-effective alternative to traditional biomass pretreatment methods.
• The developed cellulose degradation module can be integrated into larger systems for high-value molecule production.