Dimethylsulfoxide enhances phototrophic growth of Rhodobacter sphaeroides in blue light

Dimethylsulfoxide enhanced the phototrophic growth of Rhodobacter sphaeroides in blue light by enabling cells to grow to a higher culture density. This enhanced growth with dimethylsulfoxide was not due to redox poising of the cyclic photosynthetic electron transfer chain and did not involve respiration. It was demonstrated that carotenoids and cyclic electron transfer were obligatory for the effect of dimethylsulfoxide suggesting that this molecule enhances the harvesting of blue light. The enhancement of blue light-dependent phototrophic growth by dimethylsulfoxide was shown to occur at very low concentrations of this molecule and this may have some significance for the growth of phototrophic bacteria in some environments.