Sporomusa intestinalis sp. nov., a homoacetogenic bacterium isolated from the gut of a higher termite, Termes comis (Termitinae)

Abstract

The genus Sporomusa belongs phylogenetically to the family Vellionellaceae of the phylum Firmicutes. The members of this genus are known to be anaerobic or aerotolerant, homoacetogenic bacteria which grow autotrophically on H2/CO2 or heterotrophically on various substrates such as sugars, alcohols, amino acids, and organic acids. To date, the genus Sporomusa comprises nine species: Sporomusa ovata, Sporomusa sphaeroides, Sporomusa acidovorans, Sporomusa paucivorans, Sporomusa termitida, Sporomusa malonica, Sporomusa silvacetica, Sporomusa aerivorans, and Sporomusa rhizae (Boga et al., 2003; Breznak et al., 1988; Dehning et al., 1989; Gosner et al., 2006; Hermann et al., 1987; Kuhner et al., 1997; Moller et al., 1984; Ollivier et al., 1985). Of these Sporomusa species, S. termitida and S aerivorans have been isolated from wood-feeding and soil-feeding higher termites, respectively. In this paper, we describe the isolation and characterization of a novel Sporomusa species, designated strain Tc2AT (JCM13218T=DSM17189T) from the gut content of wood/soil interface-feeding higher termite, and propose a new species to accommodate it. Strain Tc2AT was obtained from the gut of the interface-feeding higher termite Termes comis (Termitinae), which was collected in Pathum Thani, Thailand. For enrichment of strain Tc2AT, the guts were dissected and homogenized, followed by inoculation into 20 ml of a strictly anaerobic bicarbonate medium (Hattori et al., 2000) supplemented with 2 mM dithiothreitol, 200 ppm Bacto yeast extract, and 40 mM bromoethane sulfonate, 2 mM sodium acetate and H2/CO2 (100 kPa, 80:20, v/v). After 3 weeks’ incubation at pH 7 and 30°C, the enrichment culture was serially diluted into the fresh medium (inoculum 10%, v/v). After the repeated transfers of the enrichment culture, they were further inoculated into the fresh medium solidified with 2% agar. It was incubated at 30°C for 2 weeks to form colonies. Isolation of strain Tc2AT was achieved by 5 successive transfers of the colony into the agar medium. The isolate was examined for physiological and biochemical characteristics. Utilization of electron donors and acceptors, efJ. Gen. Appl. Microbiol., 59, 321‒324 (2013)