BACKGROUND: A central problem in the production of lactic acid bacteria (LAB) is the low productivity conventional batch systems due to end product inhibition. This work investigated the impacts of the membrane bioreactor (MBR) on the growth of four industrially important LAB and compared the growth in pH controlled STR using Lactobacillus buchneri, L. brevis, Oenococcus oeni, and Bifidobacterium longum. RESULTS: The four LAB were grown in a pH-controlled STR batch culture and this was compared with perfusion culture of the MBR. The growth of LAB in MBR produced a far more intensive production of cells with great volumetric productivity and high cell concentrations compared with STR cultures. Total cell concentration in perfusion culture of LAB reached 13 to 23 g DCW L-1 up to 14 times higher than those obtained in the STR cultures. Overall volumetric biomass production rates in the MBR increased from 10 to 33 times that in the STR, and were organism dependent. CONCLUSION: The MBR has considerable potential for enhanced production of LAB. Limitations to growth and growth rate during perfusion culture of LAB in the MBR were from gas bubbles produced or membrane fouling. Further improvements in productivities are possible with careful design of the media, the MBR reactor and the performance characteristics of the LAB. (C) 2010 Society of Chemical Industry