Jeon Byoung Seung, Kim Seil, Sang Byoung-In
Department of Chemical Engineering, Hanyang University, 222 Wangshimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
Division of Metrology for Quality of Life, Center for Bioanalysis, Korea Research Institute of Standards and Science, 267 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea.
Int J Syst Evol Microbiol. 2017 Jul;67(7):2114-2120. doi: 10.1099/ijsem.0.001888. Epub 2017 Jul 26.
Strain MHT, a strictly anaerobic, Gram-stain-negative, non-spore-forming, spherical coccus or coccoid-shaped microorganism, was isolated from a cow rumen during a screen for hexanoic acid-producing bacteria. The microorganism grew at 30-40 °C and pH 5.5-7.5 and exhibited production of various short- and medium-chain carboxylic acids (acetic acid, butyric acid, pentanoic acid, isobutyric acid, isovaleric acid, hexanoic acid, heptanoic acid and octanoic acid), as well as H2 and CO2 as biogas. Phylogenetic analysis based on 16S rRNA gene sequencing demonstrated that MHT represents a member of the genus Megasphaera, with the closest relatives being Megapsphaera indica NMBHI-10T (94.1 % 16S rRNA sequence similarity), Megasphaera elsdenii DSM 20460T (93.8 %) and Megasphaera paucivorans DSM 16981T (93.8 %). The major cellular fatty acids produced by MHT included C12 : 0, C16 : 0, C18 : 1cis 9, and C18 : 0, and the DNA G+C content of the MHT genome is 51.8 mol%. Together, the distinctive phenotypic and phylogenetic characteristics of MHT indicate that this microorganism represents a novel species of the genus Megasphaera, for which the name Megasphaera hexanoica sp. nov. is herein proposed. The type strain of this species is MHT (=KCCM 43214T=JCM 31403T).
菌株MHT是一种严格厌氧、革兰氏染色阴性、不形成芽孢的球形球菌或类球状微生物，是在筛选产己酸细菌的过程中从奶牛瘤胃中分离出来的。该微生物在30-40 °C和pH 5.5-7.5条件下生长，能产生各种短链和中链羧酸（乙酸、丁酸、戊酸、异丁酸、异戊酸、己酸、庚酸和辛酸），以及作为沼气的H2和CO2。基于16S rRNA基因测序的系统发育分析表明，MHT属于巨球形菌属，与印度巨球形菌NMBHI-10T（16S rRNA序列相似性为94.1 %）、埃氏巨球形菌DSM 20460T（93.8 %）和寡食巨球形菌DSM 16981T（93.8 %）亲缘关系最近。MHT产生的主要细胞脂肪酸包括C12 : 0、C16 : 0、C18 : 1cis 9和C18 : 0，MHT基因组的DNA G+C含量为51.8 mol%。总之，MHT独特型和系统发育特征表明该微生物代表巨球形菌属的一个新物种，在此提出将其命名为己酸巨球形菌（Megasphaera hexanoica sp. nov.）。该物种的模式菌株为MHT（=KCCM 43214T=JCM 31403T）。
