Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA.
Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA.
Sci Adv. 2023 Sep 8;9(36):eadj0053. doi: 10.1126/sciadv.adj0053. Epub 2023 Sep 6.
Bioconversion of a heterogeneous mixture of lignin-related aromatic compounds (LRCs) to a single product via microbial biocatalysts is a promising approach to valorize lignin. Here, KT2440 was engineered to convert mixed p-coumaroyl- and coniferyl-type LRCs to β-ketoadipic acid, a precursor for performance-advantaged polymers. Expression of enzymes mediating aromatic -demethylation, hydroxylation, and ring-opening steps was tuned, and a global regulator was deleted. β-ketoadipate titers of 44.5 and 25 grams per liter and productivities of 1.15 and 0.66 grams per liter per hour were achieved from model LRCs and corn stover-derived LRCs, respectively, the latter representing an overall yield of 0.10 grams per gram corn stover-derived lignin. Technoeconomic analysis of the bioprocess and downstream processing predicted a β-ketoadipate minimum selling price of $2.01 per kilogram, which is cost competitive with fossil carbon-derived adipic acid ($1.10 to 1.80 per kilogram). Overall, this work achieved bioproduction metrics with economic relevance for conversion of lignin-derived streams into a performance-advantaged bioproduct.
通过微生物生物催化剂将木质素相关芳香族化合物（LRCs）的不均匀混合物转化为单一产物是一种有前途的木质素增值方法。在这里，通过工程改造 KT2440 以将混合的对香豆酰基和松柏酰基 LRCs 转化为β-酮己二酸，这是一种具有性能优势的聚合物的前体。调节介导芳香族脱甲基、羟基化和开环步骤的酶的表达，并删除了全局调节剂。从模型 LRCs 和玉米秸秆衍生的 LRCs 中分别获得了 44.5 和 25 克/升的β-酮己二酸产量和 1.15 和 0.66 克/升/小时的生产率，后者代表玉米秸秆衍生木质素的总收率为 0.10 克/克。生物工艺和下游加工的技术经济分析预测β-酮己二酸的最低销售价格为每公斤 2.01 美元，这与化石碳衍生的己二酸（每公斤 1.10 至 1.80 美元）具有成本竞争力。总的来说，这项工作实现了与经济相关的生物生产指标，可将木质素衍生物流转化为具有性能优势的生物制品。
