Transcriptomics-guided rational engineering in Bacillus licheniformis for enhancing poly-γ-glutamic acid biosynthesis using untreated molasses.

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  • Additional Information
    • Source:
      Publisher: Elsevier Country of Publication: Netherlands NLM ID: 7909578 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1879-0003 (Electronic) Linking ISSN: 01418130 NLM ISO Abbreviation: Int J Biol Macromol Subsets: MEDLINE
    • Publication Information:
      Publication: Amsterdam : Elsevier
      Original Publication: Guildford, Eng., IPC Science and Technology Press.
    • Subject Terms:
      Bacillus licheniformis*/genetics ; Bacillus licheniformis*/metabolism ; Polyglutamic Acid*/analogs & derivatives ; Polyglutamic Acid*/biosynthesis ; Molasses* ; Metabolic Engineering*/methods; Transcriptome ; Gene Expression Regulation, Bacterial ; Fermentation ; Gene Expression Profiling ; Bacterial Proteins/genetics ; Bacterial Proteins/metabolism
    • Abstract:
      The utilization of non-food raw materials for microbial synthesis of poly-γ-glutamic acid (γ-PGA) presents a promising alternative to conventional food-based biosynthesis. However, the complex carbon source and composition of molasses, a prevalent non-food raw material, may impose constraints on its conversion and utilization by microorganisms. This study aimed to enhance the capacity of Bacillus licheniformis to convert untreated molasses into γ-PGA through transcriptomic analysis to guide metabolic modifications. Initial results from the transcriptomic analysis indicated that the strain utilizing molasses exhibited decreased expression of genes associated with substrate utilization (Module 1) and by-product synthesis (Module 2), while upregulating genes related to precursor synthesis (Module 3). Furthermore, we performed a knockout of the acetolactate synthase (AlsS) to reduce the synthesis of metabolic by-products and a knockout of the global regulator (CcpA) to alleviate carbon catabolite repression (CCR) and then promote substrate utilization. Ultimately, following the tandem overexpression of precursor supplying key genes, the titer of γ-PGA reached 48.26 g/L with a productivity of 1.15 g/L/h, using untreated molasses as the sole carbon source, which was 3.12-fold of the starting strain. These findings offer significant insights into the cost-effective synthesis of γ-PGA by bioconversion of untreated molasses during fermentation.
      Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
      (Copyright © 2024. Published by Elsevier B.V.)
    • Contributed Indexing:
      Keywords: Poly-γ-glutamic acid; Transcriptomic analysis; Untreated molasses
    • Accession Number:
      25513-46-6 (Polyglutamic Acid)
      0 (poly(gamma-glutamic acid))
      0 (Bacterial Proteins)
    • Publication Date:
      Date Created: 20241112 Date Completed: 20241203 Latest Revision: 20241203
    • Publication Date:
      20241204
    • Accession Number:
      10.1016/j.ijbiomac.2024.137514
    • Accession Number:
      39532159