UCD School of Biosystems and Food Engineering, University College Dublin, Belfield, Dublin 4, Ireland.
UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland; UCD Conway Institute, University College Dublin, Dublin 4, Ireland.
N Biotechnol. 2024 Nov 25;83:155-162. doi: 10.1016/j.nbt.2024.08.498. Epub 2024 Aug 10.
Within the circular bioeconomy the production of optically pure LA from 2nd generation feedstocks would be ideal but it is very challenging. In this paper genetically engineered Escherichia coli strains were created to resolve racemic LA solutions synthesised and produced from the fermentation of organic waste or ensiled grass. Refining LA racemic mixtures into either a D- or L-LA was achieved by cells being able to consume one LA isomer as a sole carbon and energy source while not being able to consume the other. A D-LA refining strain JSP0005 was grown on fermented source-sorted organic household waste and different grass silage leachates, which are 2nd generation feedstocks containing up to 33 g/L lactic acid racemate. In all growth experiments, L-LA was completely removed leaving D-LA as the only LA stereoisomer, i.e. resulting in optically pure D-LA, which also increased by as much as 248.6 % from its starting concentration, corresponding to 38 g/L. The strains resulting from this study are a promising first step towards a microbial based LA biorefining process.
在循环生物经济中，从第二代原料生产光学纯 LA 是理想的，但极具挑战性。本文通过基因工程大肠杆菌菌株的创建，以解决由有机废物或青贮草发酵合成和生产的外消旋 LA 溶液。通过使细胞能够将一种 LA 异构体作为唯一的碳和能源源消耗，而不能消耗另一种异构体，从而将 LA 外消旋混合物精制为 D-或 L-LA。D-LA 精制菌株 JSP0005 以发酵的分类有机家庭废物和不同的草青贮浸出物为生长基质，这些都是含有高达 33 g/L 乳酸外消旋混合物的第二代原料。在所有生长实验中，L-LA 都被完全去除，只剩下 D-LA 作为唯一的 LA 立体异构体，即得到光学纯 D-LA，其浓度从起始浓度增加了高达 248.6%，达到 38 g/L。本研究产生的菌株是朝着基于微生物的 LA 生物精炼工艺迈出的有希望的第一步。
