First Insights into the Genome Sequence of the Strictly Anaerobic Homoacetogenic Sporomusa sphaeroides Strain E (DSM 2875)

ABSTRACT Here, we report the draft genome sequence of Sporomusa sphaeroides strain E (DSM 2875), a strict anaerobic homoacetogenic bacterium. It is able to grow autotrophically on different one-carbon compounds. The strain possesses several genes of the Wood-Ljungdahl pathway. The genome consists of a single chromosome (4.98 Mb).

Carbon Isotope Fractionation during Catabolism and Anabolism in Acetogenic Bacteria Growing on Different Substrates

ABSTRACTHomoacetogenic bacteria are versatile microbes that use the acetyl coenzyme A (acetyl-CoA) pathway to synthesize acetate from CO2and hydrogen. Likewise, the acetyl-CoA pathway may be used to incorporate other 1-carbon substrates (e.g., methanol or formate) into acetate or to homoferment monosaccharides completely to acetate. In this study, we analyzed the fractionation of pure acetogenic cultures grown on different carbon substrates. While the fractionation ofSporomusa sphaeroidesgrown on C1compounds was strong (εC1, −49‰ to −64‰), the fractionation ofMoorella thermoaceticaandThermoanaerobacter kivuiusing glucose (εGlu= −14.1‰) was roughly one-third as strong, suggesting a contribution of less-depleted acetate from fermentative processes. ForM. thermoacetica, this could indeed be validated by the addition of nitrate, which inhibited the acetyl-CoA pathway, resulting in fractionation during fermentation (εferm= −0.4‰). In addition, we determined the fractionation into microbial biomass ofT. kivuigrown on H2/CO2(εanabol.= −28.6‰) as well as on glucose (εanabol.= +2.9‰).