Carbon loss in the form of CO₂ is an intrinsic and persistent challenge faced during conventional and advanced biofuel production from biomass feedstocks. Current mechanisms for increasing carbon conservation typically require the provision of reduced co-substrates as additional reducing equivalents. This need can be circumvented, however, by exploiting the natural heterogeneity of lignocellulosic sugars mixtures and strategically using specific fractions to drive complementary CO₂ emitting vs. CO₂ fixing pathways. As a demonstration of concept, a coculture-coproduction system was developed by pairing two catabolically orthogonal Escherichia coli strains; one converting glucose to ethanol (G2E) and the other xylose to succinate (X2S). ¹³C-labeling studies reveled that G2E + X2S cocultures were capable of recycling 24% of all evolved CO₂ and achieved a carbon conservation efficiency of 77%; significantly higher than the 64% achieved when all sugars are instead converted to just ethanol. In addition to CO₂ exchange, the latent exchange of pyruvate between strains was discovered, along with significant carbon rearrangement within X2S.

CO ₂形式的碳损失是从生物质原料生产传统和先进生物燃料过程中面临的固有和持久挑战。当前增加碳保护的机制通常需要提供还原的共底物作为额外的还原当量。然而，可以通过利用木质纤维素糖混合物的天然异质性并有策略地使用特定部分来驱动互补的 CO ₂排放与 CO ₂固定途径来规避这种需求。作为概念的演示，通过配对两种分解代谢正交的大肠杆菌开发了一种共培养-共生系统菌株; 一种将葡萄糖转化为乙醇 (G2E)，另一种将木糖转化为琥珀酸酯 (X2S)。^{13 项}C 标记研究表明，G2E + X2S 共培养能够回收所有进化出的 CO _{2 的}24%，并实现了 77% 的碳节约效率；显着高于将所有糖都转化为乙醇时所达到的 64%。除了 CO ₂交换外，还发现了菌株之间丙酮酸的潜在交换，以及 X2S 内的显着碳重排。