Transcriptome analysis of Bacillus coagulans P38, an efficient producer of L-lactic acid from cellulosic hydrolysate, in response to 2-furfural stress

A comparative transcriptome analysis was conducted to study the expression profiles of the lactic acid-producing strain Bacillus coagulans P38 cultivated in the presence and absence of 2-furfural stress. In response to 7 g l(-1) 2-furfural stress, the cell growth rate of B. coagulans P38 was reduced, and a total of 740 genes were upregulated and 540 genes downregulated. KEGG pathway enrichment analysis revealed that nine pathways were significantly affected by 2-furfural stress (P < 0.01). The downregulation of glycolysis/gluconeogenesis and upregulation of the tricarboxylic acid cycle cycle revealed that L-lactic acid fermentation was negatively affected by 2-furfural stress. Gene Ontology assignments showed that five transporters and one transcriptional regulator were upregulated by more than sixfold under 2-furfural stress. The expression of seven alcohol dehydrogenase genes and eight short-chain dehydrogenase/reductase genes, all of which may be involved in the mediation of furfural tolerance, were induced under 2-furfural stress. Our findings offer new insights into the response of B. coagulans to 2-furfural stress. In addition, our RNA-seq dataset constitutes a robust database that can be used to investigate the genetic functions induced by 2-furfural stress.