一株产丁酸羊源拜氏梭菌的筛选及其培养条件优化

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

【背景】人类和动物消化道内栖息着极其复杂和多样化的微生物群落,这些微生物群落分布在肠道的不同位置并执行着特定的功能。近年来,产丁酸菌逐渐成为微生物领域的研究热点,产丁酸菌主要为产芽孢革兰氏阳性厌氧菌,对肠道健康有重要意义。【目的】从反刍动物瘤胃中筛选出产丁酸菌株并研究其生长特性,进一步优化其培养条件,从而提高产丁酸菌的丁酸产量。【方法】以绵羊瘤胃内容物为样品,运用稀释涂布法进行产丁酸菌的筛选,通过形态学观察和16S rRNA基因序列分析等方法对菌株进行鉴定。通过单因素试验与Box-Behnken design试验相结合,对培养条件进行优化,确定筛选菌株在梭菌增殖培养基(reinforced clostridium medium,RCM)中的最佳产酸培养条件。【结果】经过筛选鉴定得到的菌株为梭菌属的拜氏梭菌(Clostridium beijerinckii,CB),命名为拜氏梭菌R8(CB.R8)。对拜氏梭菌R8的培养条件进行优化,得出该菌株在接种量为1.22%、温度为38.45°C、pH 6.08和培养时间为64.67 h的条件下丁酸产量为2.48 g/L。【结论】筛选到1株拜氏梭菌R8,该菌能够在RCM培养基中生长并代谢产生丁酸,具备较高的应用价值。

[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°C,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.