Pathway engineering of Escherichia coli for the glycerol-based production of recombinant endoglucanase

Abstract

BackgroundTechnology platforms developed in biorefinery are featured with low-carbon emission but afflicted by the issue of economic viability. This can be addressed by a cascade process that prioritizes the production of value-added products. In this context, the cost-effective production of endoglucanase (encoded by celA) was illustrated using Escherichia coli with crude glycerol. This renewable and sustainable feedstock appears in abundance in waste streams of the biodiesel process. Moreover, glutamate (Glu) was supplemented to tackle the inconsistent quality of yeast extract. MethodsA new fusion tag was first explored to improve the solubility of CelA. CelA was then produced using a strain quipped with a rewired glycerol metabolism. To improve the CelA production, the producer strain was further re-programmed by manipulation of metabolic pathways involved in oxidative phosphorylation and substrate-level phosphorylation. Significant findingsThe production of CelA in the developed strain positively correlated with glycerol. It was found to increase the CelA production by 90% in the engineered strain when the glycerol level was doubled. In contrast, the parent strain gained merely 20% more production of CelA. The result indicates that the physiological status of the engineered strain is refined to favor functioning of the protein synthesis machinery. In conclusion, the developed strain shows promise in production of recombinant proteins based on crude glycerol.