The sequence was submitted to the GenBank Data Library with the accession number HM016869. The 16S rRNA gene sequence was aligned with equivalent 16S sequences of all closely related ABT-888 mouse strains found in the GenBank database via a blast search and aligned
using clustal w. The phylogenetic tree was calculated with the neighbor-joining method in the phylip package (Felsenstein, 2004). The G+C content was determined by the HPLC method (Mesbah et al., 1989). DNA–DNA homology experiments were carried out by the DSMZ Identification Service. Only one thermophilic isolate that can grow in the presence of 10% ethanol at 60 °C was isolated. The effect of exogenously added ethanol on the growth of strain E13T at the optimum growth temperature of 60 °C is presented in Fig. 1d. The results showed that the strain E13T not only tolerated high concentrations of ethanol, but grew better in the presence of an amount of ethanol. At concentrations below 6%, ethanol stimulated the growth of strain E13T when compared with a control sample incubated without ethanol. The highest growth rates were consistently attained in the presence of 2% and 4% ethanol, and 4% ethanol resulted in the highest cell yield
(final OD600 nm at stationary phase). To our knowledge, this is the first report of a wild-type thermophilic bacterium that has a preferable growth in the presence of ethanol. We define this property as ‘ethanol adaptation’, as against ethanol tolerance. selleck kinase inhibitor In addition, the ability of strain E13T to utilize ethanol was determined
by monitoring ethanol concentrations during cell growth. No significant difference in concentrations of ethanol was observed (data not shown). The results showed that the strain E13T was unable to degrade ethanol. Comparison of the growth of strain E13T at different temperatures showed that the ethanol adaptation was temperature dependent (Fig. 1). The growth rates remained relatively high up to 8% ethanol at 45 Urease and 50 °C (Fig. 1a and b), but in 8% ethanol at 55 °C, the growth rate decreased significantly although the cell yield reached under this condition was still much higher than that reached in the control sample (Fig. 1c). The addition of 8% ethanol repressed the microbial growth, causing a decrease in the achieved cell yield at 60 °C (Fig. 1d), while no increase in OD600 nm readings was observed for the ethanol concentration of 8% at 65 °C (Fig. 1e). The results indicated that ethanol adaptation increased to 8% ethanol with decreasing temperature, which was similar to previous investigations of ethanol tolerance reported in the literature (Bascaran et al., 1995; Georgieva et al., 2007). In the case of Thermoanaerobacter A10, Georgieva and colleagues demonstrated that a temperature increase of 15 °C, from 50 to 65 °C, resulted in a decrease in the critical inhibitory ethanol concentration from 6.1% to 5.5%.