Thermoflavimicrobium daqui sp. nov., a thermophilic microbe isolated from Moutai-flavour Daqu.

Abstract

Moutai-flavour Daqu is an important starter to support growth of microorganisms in the fermented process of Moutai-flavour liquor. A novel thermophilic microorganism, designated strain FBKL4.011T, was isolated from Moutai-flavour Daqu samples collected from Guotai distillery in Renhuai, Guizhou province, south-west China. The strain could grow at 45-65 °C (optimum 45 °C). Based on polyphasic analysis, strain FBKL4.011T was affiliated to the genus Thermoflavimicrobium. It formed abundant pale-yellow aerial and substrate mycelium, bearing single endospores (7.0-10.0 µm diameter) on branched long sporophores (5.0 µm diameter). The cell-wall peptidoglycan contained meso-diaminopimelic acid; ribose, glucose and mannose were the primary whole-cell sugars. The major fatty acids were iso-C14 : 0, iso-C15 : 0, anteiso-C15 : 0 and iso-C16 : 0. The predominant menaquinone were MK-8 and MK-9. The polar phospholipids contained diphosphatidyl glycerol, phosphatidyl ethanolamine, one unidentified phospholipid and one unidentified lipid. The G+C content of the genome was 43.1 mol%. According to the 16S rRNA gene sequence analysis, strain FBKL4.011T was closely related to Thermoflavimicrobium dichotomicum JCM 9688T (95.3 % sequence similarity), and other members within the family Thermoactinomycetaceae (less than 93.0 % sequence similarity). The DNA-DNA hybridisation data showed low relatedness between strain FBKL4.011T and T. dichotomicum JCM 9688T, Laceyella sacchari KCTC 9790T, Laceyella tengchongensis YIM 10002T, Laceyella sediminis RHA1T(36.7±1.1 %, 30.0±1.2 %, 21.3±2.1 % % and 37.6±0.9 %, respectively). Based on data from the polyphasic analysis, strain FBKL4.011T is considered to represent a novel species of the genus Thermoflavimicrobium, for which the name Thermoflavimicrobium daqui sp. nov. is proposed. The type strain is FBKL4.011T(=KCTC 43036T=CICC 24504T).