Synergistic substrate cofeeding stimulates reductive metabolism

Abstract

Advanced bioproduct synthesis via reductive metabolism requires coordinating carbons, ATP, and reducing agents, which are generated with varying efficiencies depending on metabolic pathways. Substrate mixtures with shortcut access concurrently to multiple pathways may optimally satisfy these biosynthetic requirements. However, native regulation favoring preferential utilization precludes cells from co-metabolizing multiple substrates. Here we explore mixed substrate metabolism and tailor pathway usage to synergistically stimulate carbon reduction. By controlled cofeeding of superior ATP-and NADPH-generators as "dopant" substrates to cells primarily utilizing inferior substrates, we circumvent catabolite repression and drive synergy in two divergent organisms. Glucose doping in Moorella thermoacetica stimulates CO 2 reduction (2.3 g/g cell /hr) into acetate by augmenting ATP synthesis via pyruvate kinase. Gluconate doping in Yarrowia lipolytica accelerates acetate-driven lipogenesis (0.046 g/g cell /hr) by obligatory NADPH synthesis through the pentose cycle. Together, synergistic cofeeding produces CO 2 -derived lipids with 38% energetic efficiency and demonstrates potential to convert CO 2 into advanced bioproducts.

Enhancing CO2-Valorization Using Clostridium autoethanogenum for Sustainable Fuel and Chemicals Production

“…To the best of our knowledge, this is the first report where supplementation of a substrate other than H 2 , increased productivities of continuous acetogenic CO 2 fermentation while maintaining net CO 2 utilization. Furthermore, the effect of CO supplementation on CO 2 utilization was superlinear, indicating a synergistic mechanism (Park et al, 2019). This is encouraging for development of bioprocesses valorizing CO 2 .…”

“…Growth and acetate production was high but no characterization of the headspace was performed. More recently, continuous glucose-supplemented CO 2 /H 2 fermentation of Moorella thermoacetica by Park et al (2019) did not lead to net uptake of CO 2 . Furthermore, Jones et al (2016) did not show net CO 2 uptake for a wide range of acetogens (not A. woodii) fermenting syngas and fructose.…”

Integration of absolute multi-omics reveals dynamic protein-to-RNA ratios and metabolic interplay within mixed-domain microbiomes

“…3). It has been shown that oxidizers can improve the oxidation of SCFAs (up to double speed) when superior NADPH and ATP generators (e.g., glucose) are consumed in small amounts to complement the stoichiometry through the pentose phosphate pathway (PPP) without triggering the shift of the entire cell's metabolism toward another substrate 38 . In this context, it is interesting to note that TEPI1 was the only MAG that encoded and expressed a hexose (allose) transporter (Fig.…”

“…Metagenomic analysis was initially performed on the SEM1b community using two different generations that had consistent population structure and was used as a supporting database for a subsequent SEM1b time-series experiment. The time series analyses consisted of metabolomics, metaproteomics, and metatranscriptomics over nine time points (at t0, 8,13,18,23,28,33,38, and 43 h) in triplicate (A, B, and C), spanning the consortium life cycle (Fig. 1b).…”

Integration of absolute multi-omics reveals translational and metabolic interplay in mixed-kingdom microbiomes

“…It has been shown that oxidizers can improve oxidization of SCFAs (up to double speed) when superior NADPH and ATP generators (e.g. glucose) are consumed in small amounts to complement the stoichiometry through the Pentose Phosphate Pathway (PPP) without triggering the shift of the entire cells metabolism toward another substrate 29 . In this context, it is interesting to note that TEPI1 was the only MAG that encoded and expressed a hexose (allose) transporter ( Fig.…”