Journal of Biotechnology & Biomaterials
Open Access

Abstract

The limited supply of intracellular malonyl-CoA in Escherichia coli impedes the biological synthesis of polyketides, flavonoids and biofuels. Here, a Clustered Regularly Inter-Spaced Short Palindromic Repeats (CRISPR) interference system was constructed for fine-tuning the central metabolic pathways to efficiently channel carbon flux toward malonyl- CoA. Using synthetic sgRNA to silence candidate genes, genes that could increase the intracellular malonyl-CoA level by over 223% were used as target genes. The efficiencies of repression of these target genes were tuned to achieve appropriate levels so that the intracellular malonyl-CoA level was enhanced without significantly altering final biomass accumulation (the final OD600 decreased by less than 10%). Based on the results, multiple gene silencing was successful in approaching the limit of the amount of malonyl-CoA needed to produce the plant-specific secondary metabolite (2S)-naringenin. By coupling the genetic modifications to cell growth, the combined effects of these genetic perturbations increased the final (2S)-naringenin titer to 421.6 mg/L which was 7.4-fold higher than the control strain (50.5 mg/L). The strategy described here could be used to characterize genes that are essential for cell growth and to develop E. coli as a well-organized cell factory for the production of other important products that require malonyl-CoA as a precursor such as flavonoids, polyketides and fatty acids.

Biography

Jingwen Zhou obtained his PhD degree in Fermentation Engineering in 2009. After that, he became Assistant Professor in 2009, Associate Professor in 2011 and Full Professor in 2014 in the School of Biotechnology, Jiangnan University. He finished his Postdoc training in Department of Chemistry and Chemical Biology in Harvard from 2012 to 2013. His current research works mainly focused on the metabolic engineering of microorganisms to produce organic acids and plant natural products, especially L-ascorbic acid and flavonoids. He published 52 peer reviewed papers in journals such as Metabolic Engineering, Applied and Environment Microbiology, and also several invited reviews on Current Opinion in Biotechnology and Biotechnology Advances. Several of the typical products he had been working on ares now produced by several manufactures on industrial scale. His achievements were awarded several times in China. He is now the Editorial Board Member of Scientific Reports (Nature Press) and Electronic Journal of Biotechnology (Elsevier Press).

Email: zhoujw1982@jiangnan.edu.cn