Nesterenkonia sp. strain F, a halophilic bacterium producing acetone, butanol, and ethanol under aerobic conditions

The moderately halophilic bacterium Nesterenkonia sp. strain F, which was isolated from Aran-Bidgol Lake (Iran), has the ability to produce acetone, butanol and ethanol (ABE) as well as acetic and butyric acids under aerobic and anaerobic conditions. This result is the first report of ABE production with a wild microorganism from a family other than Clostridia and also the first halophilic species shown to produce butanol under aerobic cultivation. The cultivation of Nesterenkonia sp. strain F under anaerobic conditions with 50 g/l of glucose for 72 h resulted in the production of 105 mg/l of butanol, 122 mg/l of acetone, 0.2 g/l of acetic acid and 2.5 g/l of butyric acid. Furthermore, the strain was cultivated on media with different glucose concentrations (20, 50 and 80 g/l) under aerobic and anaerobic conditions. Through fermentation with a 50 g/l initial glucose concentration under aerobic conditions, 66 mg/l of butanol, 125 mg/l of acetone, 291 mg/l of ethanol, 5.9 g/l of acetic acid and 1.2 g/l of butyric acid were produced. The enzymes pertaining to the fermentation pathway in the strain were compared with the enzymes of Clostridium spp. and the metabolic pathway of fermentation used by Nesterenkonia sp. strain F was investigated.