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Transcriptomics-guided rational engineering in Bacillus licheniformis for enhancing poly-γ-glutamic acid biosynthesis
Rui Han1, Qian Zhong1, Yifan Yan1
1College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China; State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
International Journal of Biological Macromolecules
|November 12, 2024
Summary
This study engineered Bacillus licheniformis to efficiently produce poly-γ-glutamic acid (γ-PGA) from untreated molasses. Metabolic modifications significantly boosted γ-PGA yield, demonstrating cost-effective bioconversion for industrial applications.
Area of Science:
- Biotechnology
- Microbial Synthesis
- Metabolic Engineering
Background:
- Poly-γ-glutamic acid (γ-PGA) is a biodegradable polymer with diverse applications.
- Utilizing non-food raw materials like molasses for γ-PGA production offers a sustainable alternative.
- Molasses's complex composition can hinder microbial conversion efficiency.
Purpose of the Study:
- To enhance Bacillus licheniformis's ability to convert untreated molasses into γ-PGA.
- To guide metabolic engineering strategies using transcriptomic analysis.
- To achieve cost-effective and high-yield γ-PGA biosynthesis.
Main Methods:
- Transcriptomic analysis of Bacillus licheniformis grown on molasses.
- Metabolic engineering strategies including gene knockouts (AlsS, CcpA) and gene overexpression.
- Fermentation optimization using untreated molasses as the sole carbon source.
Main Results:
- Transcriptomic data revealed altered gene expression in substrate utilization, by-product synthesis, and precursor synthesis modules.
- Knockout of AlsS and CcpA reduced by-product formation and alleviated carbon catabolite repression.
- Tandem overexpression of precursor genes, combined with knockouts, resulted in a γ-PGA titer of 48.26 g/L.
- Achieved a 3.12-fold increase in γ-PGA production compared to the wild-type strain.
Conclusions:
- Metabolic engineering guided by transcriptomics can significantly improve γ-PGA production from untreated molasses.
- The developed strain and process offer a cost-effective route for industrial γ-PGA synthesis.
- This study provides valuable insights for optimizing microbial bioconversion of complex, non-food feedstocks.
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