Why two are not enough: degradation of p-toluenesulfonate by a bacterial community from a pristine site in Moorea, French Polynesia.

In previous work, only one culture (strain TA12) from a pristine site was reported to utilize the xenobiotic compound p-toluenesulfonate (TSA) as a sole source of carbon and energy for aerobic growth. 'Strain TA12' has now been recognized as a community of three bacteria: Achromobacter xylosoxidans TA12-A, Ensifer adhaerens TA12-B and Pseudomonas nitroreducens TA12-C. Achromobacter xylosoxidans TA12-A and E. adhaerens TA12-B were identified as the TSA degraders. These two organisms contain several tsa genes from the Tntsa cluster described previously in Comamonas testosteroni T-2 and use the tsa pathway. Apparently, due to vitamin auxotrophy, the growth of the pure cultures with TSA was markedly slower than the growth of the community with TSA. The third bacterium (P. nitroreducens) TA12-C is, then, a provider of essential vitamins for the TSA degraders and occurs at a low frequency.