Isolation and Identification of a Strain of Clostridium butyricum with High Yield of Butyric Acid and Its Biological Characteristics

A strain of Clostridium butyricum C1-6 with high butyric acid production was isolated from faeces of healthy adults and its growth and biological characteristics were analyzed. The strain was identified in the aspects of morphological features,physiological and biochemical tests,16S rDNA gene sequence homology and multi-site sequence typing(MLST). The biological properties of the strains were evaluated by measuring the content of butyric acid in the fermentation broth,the tolerance to acid,bile salts,simulated digestive tract and antibiotic resistance. The results showed that the butyric acid content of the 24 h fermentation broth of this strain reached about 2.1 g/L. It was highly resistant to acid,bile salts and simulated digestive tract environment. The survival rate after incubation for 3 h under acidic conditions of pH2 and pH3 was 72.5% and 91.8%. The tolerance to bile salts was promoted with the increase of bile salt concentration. Its tolerance was 104.63% when the bile salt concentration was 1%. And its survival rate was still above 93% after undergoing simulated the digestive tract environment. This strain was sensitive to ampicillin,tetracycline,vancomycin,and cefuroxime except certain aminoglycoside antibiotics such as chloramphenicol and kanamycin,and penicillin. It was necessary to further evaluate the risk of antibiotic resistance genes transfer. From the above results,C. butyricum C1-6 has application potential.