Characterization and culture on sugarcane molasses of Gordonia polyisoprenivorans CCT 7137, a new strain isolated from contaminated groundwater in Brazil

The actinomycete strain Lg, which was isolated from groundwater contaminated with leachate flowing out of a former municipal landfill site (upstate Sao Paulo, Brazil) and found to produce exopolysaccharides, was analysed by polyphasic taxonomy. The growth of this strain on sugarcane molasses, at various concentrations from 2% to 10%, and on the standard glucose-yeast-maltose (GYM) medium was observed by monitoring the optical density of the culture at 600 nm. Lg was found to be Gram-positive, catalase-positive, oxidase-negative, non-motile, non-sporing and did not reduce nitrate. Morphological, biochemical, chemotaxonomic and molecular tests indicated that Lg has properties typical of Gordonia polyisoprenivorans and this new strain was thus named G. polyisoprenivorans CCT 7137. Growth of the bacterium in the experimental media was notably affected by the molasses content, being fastest at 2% and 3%, the lowest contents, the maximum specific growth-rates being 0.157 h−1 and 0.168 h−1, respectively. These rates were greater than those achieved at higher concentrations and of the same order as the rate in GYM medium, 0.175 h−1. CCT 7137 is one of six strains of G. polyisoprenivorans so far isolated and recorded in the literature, and one of the two found in contaminated groundwater. This is the first known study of the growth of a strain of G. polyisoprenivorans in GYM medium and on sugarcane molasses as sole source of nutrients. The latter is proposed as a potential substrate for production of this strain.