Recombinant Protein Production with Escherichia coli in Glucose and Glycerol Limited Chemostats

Abstract

Recently, there has been a resurgence of interest in continuous bioprocessing as a cost-optimised production strategy, driven by a rising global requirement for recombinant proteins used as biological drugs. This strategy could provide several benefits over traditional batch processing, including smaller bioreactors, smaller facilities, and overall reduced plant footprints and investment costs. Continuous processes may also offer improved product quality and minimise heterogeneity, both in the culture and in the product. In this paper, a model protein, green fluorescent protein (GFP) mut3*, was used to test the recombinant protein expression in an Escherichia coli strain with industrial relevance grown in chemostat. An important factor in enabling stable productivity in continuous cultures is the carbon source. We have studied the viability and heterogeneity of the chemostat cultures using a chemically defined medium based on glucose or glycerol as the single carbon source. As a by-product of biodiesel production, glycerol is expected to become a sustainable alternative substrate to glucose. We have found that although glycerol gives a higher cell density, it also generates higher heterogeneity in the culture and a less stable recombinant protein production. We suggest that manipulating the balance between different subpopulations to increase the proportion of productive cells may be a possible solution for making glycerol a successful alternative to glucose.

ICOR: improving codon optimization with recurrent neural networks

“…For instance, producing malaria vaccine FALVAC-1 [ 2 ] involves designing synthetic plasmids, transfection into the Escherichia coli ( E. coli ) host factory, growing the cells, and harvesting the resulting protein [ 3 ]. E. coli is well-established as a host for heterologous expression [ 4 ], however, codon bias limits the use of E. coli as an expression platform [ 5 ]. To increase the efficiency of recombinant expression in E. coli , improving codon optimization is an area of particular interest.…”