2,3-Butanediol Production by Acetogenic Bacteria, an Alternative Route to Chemical Synthesis, Using Industrial Waste Gas.

2,3-butanediol (23BD) is a high value chemical usually produced petro-chemically, but which can also be synthesized by some bacteria. To date, the best microbial 23BD production rates have been observed using pathogenic bacteria in fermentation systems that depend on sugars as the carbon and energy source for product synthesis. Here we present evidence of 23BD production by three non-pathogenic acetogenic Clostridium species C. autoethanogenum, C. ljungdahlii, and C. ragsdalei using carbon monoxide containing industrial waste gases or syngas as the sole source of carbon and energy. Through an analysis of the C. ljungdahlii genome the complete pathway from carbon monoxide to 23BD has been proposed. Homologues of the genes involved in this pathway were also confirmed in the other two species investigated. A gene expression study demonstrates a correlation between mRNA accumulation from 23BD biosynthetic genes and the onset of 23BD production, while a broader expression study of Wood-Ljungdahl pathway genes provides a transcriptional level view of one of the oldest existing biochemical pathways. [ABSTRACT FROM AUTHOR]