Detection of butyrate from a Clostridium cluster I (Clostridium sensu stricto) strain, Clostridium tertium, under anaerobic condition

Lactic acid bacteria and bacillus bifidus are well-known as probiotics used as alternative drugs confronting infectious disease, however, butyric acid (butyrate) bacteria such as Clostridium butyricum are also useful probiotics but little-known in any part of the world. To discover a new bacteria species producing butyrate, we examined the production of organic acid including butyrate in Clostridium tertium and C. butyricum. Protein BLAST (BLASTP) searches on Butyrate kinase (BUK) proteins in the genomes of C. tertium have identified 2 proteins. To confirm their presence in the genome of C. tertium, we detected two buk genes by the polymerase chain reaction (PCR). As phosphotransbutyrylase (ptb), a buk gene adjacent gene, is also present in the announced genome of C. tertium, we confirmed its presence similarly by PCR. Next, we investigated the production of butyrate in C. tertium. Lactic acid (lactate), formic acid (formate), acetic acid (acetate) and butyrate were detected in both thioglycolate medium cultures. Thus, we conclude C. tertium produces butyrate. Our findings provide a new butyrate producing bacterium as a potential probiotic.