Microorganisms of interesting metabolic properties include non-pathogenic bacteria of the genus Clostridium. The genus Clostridium is one of the largest in the Kingdom of Prokaryotes. These are anaerobic heterogenic bacteria, typically Gram-positive. Their distinctive feature is a cylindrical shape. Cells of bacteria of the genus Clostridium are ciliated, mobile and capable of forming endospores. For most species, the optimum growth temperature falls within the 30–40 °C range, while the optimum pH is contained in the 6.5–7.5 range.
C. butyricum is a typical butyric acid bacterium found in soil and intestines of healthy animals and humans. An increasing number of reports on the probiotic potential of C. butyricum have been published. C. butyricum also plays a considerable role in soil mineralization processes and conversion of organic matter. A well-known property of C. butyricum is their ability to produce butyric acid and hydrogen, as well as effectively convert glycerol to 1,3-propanediol. We have characterized potent features of C. butyricum specific isolates in terms of their phylogenetic affiliation, fermentation capacity and antibacterial properties.
Butyric acid has several potential applications in industry. Its applications in the foodstuffs and beverage industries are widespread. Biochemistry of butyrate formation is commonly accepted. The key reactions of butyrate synthesis is formation of butyryl-CoA. It is endergonic ferredoxin reduction with NADH coupled to exergonic crotonyl-CoA reduction with NADH catalyzed by the butyryl CoA dehydrogenase/Etf complex (Bcd/EtfAB complex): 2NADH + Fdox + crotonyl-CoA → 2 NAD + Fdred + butyryl-CoA. Biochemistry of the reaction has been described for Clostridium kluyveri and then confirmed in other Firmicutes. Genomes searches have revealed that genes encoding CoA dehydrogenase and Etf complex are commonly found in butyrate producing Firmicutes.
Butyrate is a typical product of hydrogen-yielding saccharolytic clostridial-type fermentation. Butyric acid production is bacterial fermentation well-recognized for many saccharolytic species of Clostridium. C. butyricum is able to convert lactate and acetate to butyrate. One strain of C. butyricum preserved in our company has been screened and identified as a probiotic bacterium. Use liquid growth medium M9 and clostridial differential medium for the cultivation of C. butyricum to obtain butyrate. For butyric acid production, batch, fed-batch, continuous and cell-recycle-fermentations are most frequently used. Comparison of the batch and fed-batch fermentation has shown that fed-batch fermentation mode could significantly enhance butyric acid production. We can provide useful information and comprehensive services for designing scale-up strategies for process optimization.
