China National Research Institute of Food and Fermentation Industries, Beijing 100027, PR China.
Academy of Biological Science and Technology, Beijing Forestry University, Beijing 100083, PR China.
Int J Syst Evol Microbiol. 2014 Jan;64(Pt 1):206-210. doi: 10.1099/ijs.0.055509-0. Epub 2013 Sep 18.
Daqu is a fermentation starter used in the production of Chinese liquors. A thermophilic bacterium, designated strain H-18(T), was isolated from a high-temperature Daqu sample collected from the manufacturing process of a sesame-flavoured liquor in Shandong province, China. It was investigated in a taxonomic study using a polyphasic approach. Strain H-18(T) formed white aerial mycelium and greyish-yellow substrate mycelium, bearing single endospores on aerial and substrate hyphae or on unbranched short sporophores. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The major fatty acids were iso-C15 : 0 and iso-C17 : 0. The predominant menaquinone was MK-7. These chemotaxonomic properties are similar to those of members of the genus Thermoactinomyces. The G+C content of the genomic DNA was 49.1 mol%. 16S rRNA gene sequence comparisons indicated that strain H-18(T) was most closely related to Thermoactinomyces vulgaris KCTC 9076(T) (96.42 % similarity), Thermoactinomyces intermedius KCTC 9646(T) (96.06 %), Laceyella putida KCTC 3666(T) (96.32 %) and Laceyella sacchari KCTC 9790(T) (95.55 %). Strain H-18(T) showed low DNA-DNA relatedness (40.8, 33.4, 20.0 and 14.4 %) with the above strains. Based on morphological and chemotaxonomic characteristics, DNA-DNA hybridization data and physiological properties, strain H-18(T) represents a novel species of the genus Thermoactinomyces, for which the name Thermoactinomyces daqus sp. nov. is proposed. The type strain is H-18(T) ( = DSM 45914(T) = CICC 10681(T)).
大曲是中国白酒生产中使用的发酵剂。从中国山东省芝麻香型白酒酿造过程中采集的高温大曲中分离出一株嗜热细菌，命名为 H-18(T) 菌株。该菌株通过多相分类研究进行了研究。H-18(T) 菌株形成白色气生菌丝和灰黄色基内菌丝，在气生和基内菌丝或不分枝的短孢子梗上产生单个内生孢子。细胞壁肽聚糖含有内消旋二氨基庚二酸。主要脂肪酸为 iso-C15:0 和 iso-C17:0。主要的menaquinone 是 MK-7。这些化学分类特征与 Thermoactinomyces 属的成员相似。基因组 DNA 的 G+C 含量为 49.1 mol%。16S rRNA 基因序列比较表明，H-18(T) 菌株与Thermoactinomyces vulgaris KCTC 9076(T)（96.42%相似性）、Thermoactinomyces intermedius KCTC 9646(T)（96.06%相似性）、Laceyella putida KCTC 3666(T)（96.32%相似性）和 Laceyella sacchari KCTC 9790(T)（95.55%相似性）最为密切相关。H-18(T) 菌株与上述菌株的 DNA-DNA 同源性分别为 40.8%、33.4%、20.0%和 14.4%。基于形态学和化学分类特征、DNA-DNA 杂交数据和生理特性，H-18(T) 菌株代表 Thermoactinomyces 属的一个新种，命名为Thermoactinomyces daqus sp. nov.。模式菌株为 H-18(T)（=DSM 45914(T)=CICC 10681(T)）。
