CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, Braga, Portugal.
CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, Braga, Portugal.
Biotechnol Adv. 2021 Mar-Apr;47:107697. doi: 10.1016/j.biotechadv.2021.107697. Epub 2021 Jan 26.
The implementation of biorefineries for a cost-effective and sustainable production of energy and chemicals from renewable carbon sources plays a fundamental role in the transition to a circular economy. The US Department of Energy identified a group of key target compounds that can be produced from biorefinery carbohydrates. In 2010, this list was revised and included organic acids (lactic, succinic, levulinic and 3-hydroxypropionic acids), sugar alcohols (xylitol and sorbitol), furans and derivatives (hydroxymethylfurfural, furfural and furandicarboxylic acid), biohydrocarbons (isoprene), and glycerol and its derivatives. The use of substrates like lignocellulosic biomass that impose harsh culture conditions drives the quest for the selection of suitable robust microorganisms. The yeast Saccharomyces cerevisiae, widely utilized in industrial processes, has been extensively engineered to produce high-value chemicals. For its robustness, ease of handling, genetic toolbox and fitness in an industrial context, S. cerevisiae is an ideal platform for the founding of sustainable bioprocesses. Taking these into account, this review focuses on metabolic engineering strategies that have been applied to S. cerevisiae for converting renewable resources into the previously identified chemical targets. The heterogeneity of each chemical and its manufacturing process leads to inevitable differences between the development stages of each process. Currently, 8 of 11 of these top value chemicals have been already reported to be produced by recombinant S. cerevisiae. While some of them are still in an early proof-of-concept stage, others, like xylitol or lactic acid, are already being produced from lignocellulosic biomass. Furthermore, the constant advances in genome-editing tools, e.g. CRISPR/Cas9, coupled with the application of innovative process concepts such as consolidated bioprocessing, will contribute for the establishment of S. cerevisiae-based biorefineries.
从可再生碳源中以具有成本效益和可持续的方式生产能源和化学品的生物精炼厂的实施在向循环经济的转型中发挥着基础性作用。美国能源部确定了一组可以从生物精炼厂碳水化合物中生产的关键目标化合物。2010 年，该清单进行了修订，其中包括有机酸（乳酸、琥珀酸、戊二酸和 3-羟基丙酸）、糖醇（木糖醇和山梨糖醇）、呋喃及其衍生物（羟甲基糠醛、糠醛和糠酸）、生物碳氢化合物（异戊二烯）以及甘油及其衍生物。使用木质纤维素生物质等基质会带来苛刻的培养条件，这促使人们寻求合适的、稳健的微生物选择。工业过程中广泛使用的酵母酿酒酵母（Saccharomyces cerevisiae）已被广泛用于生产高价值化学品。由于其稳健性、易于处理、遗传工具箱和在工业环境中的适应性，酿酒酵母是建立可持续生物工艺的理想平台。考虑到这些因素，本综述重点介绍了已应用于酿酒酵母的代谢工程策略，用于将可再生资源转化为之前确定的化学目标。每种化学物质及其制造工艺的异质性导致每个工艺的开发阶段之间不可避免的差异。目前，在这 11 种高价值化学品中，有 8 种已经通过重组酿酒酵母生产出来。虽然其中一些仍处于早期概念验证阶段，但其他一些，如木糖醇或乳酸，已经可以从木质纤维素生物质中生产。此外，基因组编辑工具（例如 CRISPR/Cas9）的不断进步，加上创新性工艺概念（例如整合生物加工）的应用，将有助于建立基于酿酒酵母的生物精炼厂。
