Determination of an economical medium for growth of Clostridium butyricum TK2 using orthogonal test

Clostridium butyricum is a widely utilized probiotics, also used as an alternative to antibiotics for humans and growth promotion in a wide variety of livestock species. The objective of this study is to develop an economical and practical fermentation medium for the growth of C. butyricum TK2 using orthogonal test. The optimal fermentation medium was obtained by the single factor and the orthogonal test of carbon source, nitrogen source and growth factors design. The fermentation medium was estimated to be the most economical formula (per liter): 8 g glucose, 20 g soybean meal (hydrolyzed for 3 h by neutral protease), 5 g brewer's yeast powder. After incubating for 48 h in the optimum fermentation medium, the populations of C. butyricum TK2 were estimated to be 8 x 10(8) CFU ml(-1), while the cost was 90% lower than ever. The optimized medium is not only more economical but also good for the growth of C. butyricum TK2. The low cost medium developed in this study can be used for large-scale commercial application where economics are quite likely to be important.