Biomanufacturing can play a pivotal role in the transition away from fossil fuel dependence for the production of chemicals and fuels. There is growing interest in alternative bioproduction feedstocks to conventional sugars that do not compete for land use with food production. Ethylene glycol, a C2 compound that can be recovered from plastic waste or derived from carbon dioxide with increasing efficiency, is gaining attention as a carbon source for microbial processes. Here we review the natural and synthetic metabolic pathways currently available for ethylene glycol assimilation. The pathways are compared in terms of their maximum theoretical yields for biomass and value-added products, thermodynamic favourability, minimum enzyme costs, and orthogonality to central carbon metabolism. We find that synthetic pathways outperform their natural counterparts in terms of higher thermodynamic driving forces, reduced enzyme costs, and higher theoretical yields for the majority of bioproducts analyzed as well as for biomass. However, natural assimilation pathways are equally or even more orthogonal to growth-associated reactions than synthetic pathways. Given these tradeoffs, the optimal EG assimilation pathway may depend on product and process choice.

中文翻译：

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乙二醇同化的合成代谢途径优于天然途径


生物制造可以在化学品和燃料生产摆脱对化石燃料依赖的转变中发挥关键作用。人们对传统糖的替代生物生产原料越来越感兴趣，这些原料不会与粮食生产竞争土地使用。乙二醇是一种 C2 化合物，可以从塑料废物中回收或从二氧化碳中提取，效率不断提高，作为微生物过程的碳源而受到关注。在这里，我们回顾了目前可用于乙二醇同化的天然和合成代谢途径。这些途径在生物质和增值产品的最大理论产量、热力学有利性、最小酶成本以及与中心碳代谢的正交性方面进行了比较。我们发现，对于大多数分析的生物产品以及生物质而言，合成途径在更高的热力学驱动力、更低的酶成本和更高的理论产量方面优于天然途径。然而，与合成途径相比，自然同化途径与生长相关反应同等甚至更加正交。考虑到这些权衡，最佳的 EG 同化途径可能取决于产品和工艺的选择。