High Cell Density Cultivation (HCDC) of E. coli with Intensive Multiple Sequential Batches Together with Fed-Batch at Cell Level (FBC) Superior to the Fed-Batch Technique

Abstract

Abstract High cell density cultivation (HCDC) is a technique that was developed and used in the cultivation of various microorganisms. Escherichia coli is the most prominent in the bacterial group and popular at the industrial scale for the production of bio-products. The HCDC conducted with the Fed-Batch modes is complicated. In this study, we developed a batch production medium (BPM), a minimal defined medium for industrial utilization with the potential use of dextrin at high concentrations as the major carbon source. Dextrin prevents cell cultivation system from the Crabtree effect due to its gradual hydrolysis to release glucose and gradual assimilation into E. coli cells like Fed-Batch at Cell Level (FBC). Yeast extract was added into the BPM to enhance cell growth. It was operated using 5-L bioreactors with the aerobic batch cultivation at high concentrations of dextrin, i.e., 90 g/L to achieve high-cell-density concentration at a high production rate superior to the Fed-Batch technique. Further, the Intensive Multiple Sequential Batch (IMFB) technique was developed to achieve a high yield at a high productivity. The maximum values of cell biomass, x; specific growth rate; yield coefficient, Yx/s; productivity, rx; and efficiency (Ef) were 46.31 g/L, 0.54 h-1, 0.55 g/g, 3.86 g/L/h and 98%, respectively. The results showed that cell cultivations and growth kinetics, biochemical engineering mass balances, and design of impeller speeds using fluid dynamics in the 5-L bioreactor of aerobic batch cell cultivation for the production of E. coli cell biomass a high-density concentration using dextrin to control the FBC at a high titer can be used for the scale-up of industrial bioreactors.