Growth of Rhodopseudomonas capsulata on l- and d-malic acid

d-malate replaced l-malate in supporting both photosynthetic (anaerobic, light) and heterotrophic (aerobic, dark) growth of Rhodopseudomonas capsulata. Growth rates and cell yields were nearly equivalent with both enantiomorphs. Addition of glucose to malate culture media increased the growth rate and doubled the cell yield of heterotrophic cultures, but had little effect on photosynthetic cultures. Aerobically-grown cells showed a higher level of substrate-dependent oxygen uptake with l-malate than with d-malate. This preference for l-malate occured even in cells grown on d-malate. No malic racemase activity was detected in extracts of heterotrophically- or photosynthetically-grown cells.