Microbial metabolism offers a wide variety of opportunities to produce chemicals from renewable resources. Employing such processes of industrial biotechnology provides valuable means to fight climate change by replacing fossil feedstocks by renewable substrate to reduce or even revert carbon emission. Several yeast species are well suited chassis organisms for this purpose, illustrated by the fact that the still largest microbial production of a chemical, namely bioethanol is based on yeast. Although production of ethanol and some other chemicals is highly efficient, this is not the case for many desired bulk chemicals. One reason for low efficiency is carbon loss, which decreases the product yield and increases the share of total production costs that is taken by substrate costs. Here we discuss the causes for carbon loss in metabolic processes, approaches to avoid carbon loss, as well as opportunities to incorporate carbon from CO₂, based on the electron balance of pathways. These aspects of carbon efficiency are illustrated for the production of succinic acid from a diversity of substrates using different pathways.

中文翻译：

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用酵母进行化学品的碳高效生产

微生物代谢为利用可再生资源生产化学品提供了多种机会。采用此类工业生物技术流程，通过用可再生基质替代化石原料来减少甚至恢复碳排放，为应对气候变化提供了宝贵的手段。几种酵母菌种是非常适合此目的的底盘生物，事实证明，仍然最大的化学品（即生物乙醇）的微生物生产是基于酵母的。尽管乙醇和一些其他化学品的生产效率很高，但许多所需的散装化学品的情况并非如此。效率低下的原因之一是碳损失，这会降低产品产量并增加底物成本在总生产成本中所占的份额。在这里，我们讨论代谢过程中碳损失的原因、避免碳损失的方法，以及基于途径的电子平衡从CO _{2中吸收碳的机会。}碳效率的这些方面通过使用不同途径从多种底物生产琥珀酸来说明。