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

摘要:

【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℃、pH6.08和培养时间为64.67h的条件下丁酸产量为2.48g/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。

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.