Enhanced isobutanol production from acetate by combinatorial overexpression of acetyl‐CoA synthetase and anaplerotic enzymes in engineered Escherichia coli

Abstract

Acetic acid is an abundant material that can be used as a carbon source by microorganisms. Despite its abundance, its toxicity and low energy content make it hard to utilize as a sole carbon source for biochemical production. To increase acetate utilization and isobutanol production with engineered Escherichia coli, the feasibility of utilizing acetate and metabolic engineering was investigated. The expression of acs, pckA, and maeB increased isobutanol production by up to 26%, and the addition of TCA cycle intermediates indicated that the intermediates can enhance isobutanol production. For isobutanol production from acetate, acetate uptake rates and the NADPH pool were not limiting factors compared to glucose as a carbon source. This work represents the first approach to produce isobutanol from acetate with pyruvate flux optimization to extend the applicability of acetate. This technique suggests a strategy for biochemical production utilizing acetate as the sole carbon source.

Biobutanol: New era of biofuels

“…are some of the example of genetically modified butanol producer organisms. 84,88,89 8 | STATUS OF BUTANOL PRODUCTION Acetone-butanol-ethanol (ABE) fermentation by C. acetobutylicum is one of the oldest known industrial fermentation processes and ranked second only to ethanol fermentation by yeast in its scale of production. However, since 1950's industrial ABE fermentation declined continuously, almost all butanol is now produced via petrochemical routes.…”

Microbial Upgrading of Acetate into 2,3-Butanediol and Acetoin by E. coli W

“…Moreover, acetate can also be produced in gas fermentations relying on C1 compounds which enables production in a cascaded process with two steps [11]. A broad spectrum of chemicals has already been produced from acetate such as polyhydroxyalkanoates [12], 3-hydroxypropionic acid [13] and succinate [14], and also alcohols like ethanol [15], isopropanol [16] and isobutanol [17]. So far, the vast majority of products that have been produced from acetate is derived from acetyl-CoA.…”

“…1) [18,21]. A combined overexpression of pckA, the malic enzymes and acs showed improved isobutanol production from acetate [17].…”

Improving isobutanol productivity through adaptive laboratory evolution in Saccharomyces cerevisiae

“…Isobutanol has received more attentions as one of second generation biofuels that are compatible with current infrastructure due to their energy density and lower moisture absorption [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Budding yeast Saccharomyces cerevisiae can produce low amount of isobutanol via valine synthesis pathway [16][17][18].…”