Penambahan glutamat sebagai pelindung tekanan osmosis dalam kondisi pembiakan etanol tinggi pada rekombinan Escherichia coli

Abstract

Enhancement of Escherichia coli recombinant cell growth in high ethanol culture conditions was investigated by additional glutamate as osmoprotectant. It was also supported by analysis of dry cell weight (DCW), glucose uptake, and acetate accumulation. Escherichia coli cells were grown under aerobic conditions with ethanol and glutamate addition in the culture time of t = 6 h. In high ethanol culture conditions (20 g/l ethanol) without glutamate acid additions, DCW and glucose uptake reached in 0.91±0.14 g/l and 13.23±0.89 g/l, respectively. These values were lower than culture conditions with 2 g/l glutamate acid additions (1.8±0.03 g/l DCW and 17.75±0.43 g/l glucose uptake), which also suppressed the accumulation of acetate in 3.29 g/l. Based on carbon flow in central carbon metabolism, the accumulation of acetate was suppressed by glutamate additions in the culture because the carbon flow diversion to tricarboxylic acid (TCA) cycle instead of entering the acetate. The accumulation of acetate also showed as a result of an overflow metabolism by high rate of glucose uptake and oxygenation level.