Screening and culture condition optimization of a butyrate-producing Clostridium beijerinckii strain from sheep

Abstract:

[Background] The digestive tracts of humans and animals harbor complex microbiota composed of diverse species which inhabit different parts of the intestine and perform specific functions. In recent years, butyrate-producing bacteria have gradually become a research hotspot in microbiology. Butyrate-producing bacteria are mainly spore-forming Gram-positive anaerobic bacteria, which are of great significance to intestinal health.[Objective] To screen butyrate-producing bacteria from the rumen of ruminants and study its growth characteristics, and further optimize its culture conditions to improve the butyrate production. [Methods] Butyrate-producing bacteria were screened from sheep rumen contents by dilution coating method and identified via morphological observation and 16S rRNA gene sequence analysis. Single factor test and Box-Behnken design were employed to optimize the acid producing conditions of the screened strain in reinforced Clostridium medium (RCM). [Results] The strain screened and identified was Clostridium beijerinckii and was named C.beijerinckii R8. The butyrate production of C.beijerinckii R8 reached 2.48 g/L under the conditions of 1.22% inoculation amount, 38.45 ℃, and pH 6.08 for 64.67 h. [Conclusion] A strain of C.beijerinckii R8 was screened, which grows and produces butyrate in RCM, demonstrating a high application value.