Production of L-lactic acid from metabolically engineered strain of Enterobacter aerogenes ATCC 29007.

In this study, L-lactic acid production was investigated from metabolically engineered strain of E. aerogenes ATCC 29007. The engineered strain E. aerogenes SUMI01 (Δ pta ) was generated by the deletion of phosphate acetyltransferase ( pta ) gene from the chromosome of E. aerogene s ATCC 29007 and deletion was confirmed by colony PCR. Under the optimized fermentation conditions, at 37 °C and pH 6 for 84 h, the L-lactic acid produced by engineered strain E. aerogenes SUMI01 (Δ pta ) in flask fermentation using 100 g/L mannitol as the carbon source was 40.05 g/L as compared to that of the wild type counterpart 20.70 g/L. At the end of the batch fermentation in bioreactor the production of L-lactic acid reached to 46.02 g/L and yield was 0.41 g/g by utilizing 112.32 g/L mannitol. This is the first report regarding the production of L-lactic acid from Enterobacter species. We believe that this result may provide valuable guidelines for further engineering Enterobacter strain for the improvement of L-lactic acid production. [ABSTRACT FROM AUTHOR]