Comparative transcriptome analysis of Bacillus subtilis responding to dissolved oxygen in adenosine fermentation

Area of Science:

• Biotechnology
• Microbial Fermentation
• Metabolic Engineering

Background:

• Dissolved oxygen (DO) is critical for adenosine fermentation.
• Previous studies indicated low oxygen supply optimizes adenosine yield in B. subtilis.

Purpose of the Study:

• To systematically investigate the effect of dissolved oxygen on genetic regulation and metabolism in B. subtilis (ATCC21616) during fermentation.
• To elucidate the link between oxygen levels and adenosine productivity through transcriptome analysis.

Main Methods:

• Utilized microarrays to analyze temporal transcript profiles of B. subtilis under high (700 r/min) and low (450 r/min) oxygen supply conditions.
• Conducted transcriptome analysis on 4,106 genes to assess metabolic and genetic responses to varying oxygen levels.

Main Results:

• Low oxygen supply significantly enhanced carbon metabolism, including glucose and pyruvate metabolism, and carbon overflow.
• Low oxygen inhibited the degradation of nitrogen sources (glutamate family amino acids, xanthine) and purine synthesis.
• Inhibition of xanthine degradation was identified as the primary mechanism for increased adenosine production under low oxygen.

Conclusions:

• Low dissolved oxygen levels promote adenosine production by modulating B. subtilis metabolism and gene expression.
• Identified specific metabolic pathways (e.g., xanthine degradation) and targets for genetic modification to improve adenosine yield.
• Provided novel insights into the intricate relationship between oxygen availability and microbial metabolism for enhanced bioproduction.