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Updated: May 15, 2026
13:51
The MultiBac Protein Complex Production Platform at the EMBL
Published on: July 11, 2013
Multi-Level Engineering of Bacillus Subtilis for High-Level Extracellular Production of Functional Expansins
Fang Luan1,2, Yangyang Li1,2, Xianhao Xu1,2
1Science Center for Future Foods, Jiangnan University, Wuxi, China.
Biotechnology Journal
|March 4, 2026
Summary
This study engineered Bacillus subtilis for high-level expansin production, achieving record yields for agricultural biotechnology and bioprocessing applications. Microbial expansins demonstrated enhanced cellulose degradation, improving biomass deconstruction efficiency.
Area of Science:
- Biotechnology
- Microbial Engineering
- Protein Production
Background:
- Expansins are crucial for plant cell growth and biomass deconstruction.
- Plant-derived expansins face limitations in industrial production due to low abundance and inconsistency.
Purpose of the Study:
- To develop a microbial system for high-level extracellular production of expansins.
- To engineer Bacillus subtilis for enhanced production of BsEXLX1 and LeEXP2 expansins.
Main Methods:
- Multi-level engineering of Bacillus subtilis, including promoter screening, RBS and signal peptide optimization.
- Fed-batch culture in a 5-L bioreactor for scale-up.
- Assessing expansin function in cellulose degradation.
Main Results:
- Achieved extracellular production of 232.3 mg/L BsEXLX1 and 15.6 mg/L LeEXP2 in shake flasks.
- Reached 1.3 g/L BsEXLX1 and 43.7 mg/L LeEXP2 in a 5-L bioreactor, the highest reported in B. subtilis.
- Microbial expansins showed synergistic effects on cellulose degradation, enhancing sugar release.
Conclusions:
- Established a scalable B. subtilis platform for high-level functional expansin production.
- Demonstrated a transferable framework for efficient extracellular protein production in B. subtilis.
- Microbial expansins hold promise for bioprocessing and biomass deconstruction.
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