Screening for optimal protease producing Bacillus licheniformis strains with polymer-based controlled-release...

Area of Science:

• Biotechnology and microbial process development
• Industrial microbiology and strain engineering

Background:

• Fed-batch conditions prevent metabolic issues common in industrial production.
• Microtiter plate batch screening misrepresents microbial physiology compared to production.
• Controlled-release fed-batch microtiter plates (fed-batch MTP) bridge screening and production gaps.

Purpose of the Study:

• Establish a glucose-limited fed-batch screening procedure using fed-batch MTP.
• Evaluate the predictability of protease-producing Bacillus licheniformis strains.
• Compare fed-batch MTP screening with traditional batch screening and lab-scale fermenters.

Main Methods:

• Developed a two-step batch preculture for consistent initial growth in fed-batch MTP.
• Utilized disposable polymer-based controlled-release fed-batch MTP for glucose-limited cultivation.
• Screened 13 industrially relevant Bacillus licheniformis clones and compared results to lab-scale fermenter data.

Main Results:

• Fed-batch MTP screening achieved ±10% standard deviation in protease activity.
• A minimum of 6 parallel cultivations were required for statistically significant clone identification.
• 92% of clones were classified similarly using fed-batch MTP screening versus 38% using batch screening.

Conclusions:

• Glucose-limited fed-batch screening in microtiter plates significantly improves predictability of clone performance.
• Fed-batch MTP screening accurately identifies improved protease-producing Bacillus licheniformis strains.
• Fed-batch MTP is an efficient high-throughput tool for bridging the screening-production gap.