Development of a Rhodococcus opacus Cell Factory for Valorizing Lignin to Muconate
Development of a Rhodococcus opacus Cell Factory for Valorizing Lignin to Muconate
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开发用于将木质素稳定为粘康酸的混浊红球菌细胞工厂
DOI：
10.1021/acssuschemeng.9b06571
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发表时间：
2020-02-03
影响因子：
8.4
通讯作者：
Jin, Mingjie
中科院分区：
文献类型：
--
作者：
Cai, Chenggu;Xu, Zhaoxian;Jin, Mingjie
由于自然界中存在多种木质素合成和降解的生物化学途径，通过生物途径实现木质素的增值引起了人们的广泛关注。顺，顺-粘康酸酯是木质素生物降解过程中常见的代谢中间体，是合成多种聚合物的重要平台化合物。在这项工作中，不透明红球菌PD 630，这是有效的芳香族化合物的同化，是第一次修改积累顺式，顺式粘康酸从木质素和木质素衍生的芳香族化合物。为了实现对R. opacus PD 630，构建了一个基于突变型苯丙氨酰-tRNA合成酶基因作为反选择标记的无标记基因缺失/插入系统。利用基因缺失/插入系统，对几个R. opacus PD 630突变体成功构建用于使用邻苯二酚和原儿茶酸作为两个关键漏斗节点从木质素衍生的芳族化合物生产顺式，顺式-粘康酸。结果表明，所构建的菌株能够同化至少15种木质素衍生的芳烃和真实的木质素以生产顺，顺-粘康酸。此外，乳糖酶的添加和H2SO 4 + NaOH组合预处理增强了真实的木质素对顺，顺-粘康酸酯的还原。最终，利用玉米秸秆木质素作为底物，通过流加发酵工艺，产生1.63g/L的顺，顺-粘康酸。总的来说，这些结果突出了使用R的巨大潜力。Opacus作为细胞工厂用于将木质素稳定为顺式、顺式-粘康酸酯和其它有价值的产物。
As multiple biochemical pathways exist in nature for lignin synthesis and degradation, lignin valorization through biological pathways has attracted much attention. cis,cis-Muconate, a common metabolic intermediate in lignin biodegradation, is an important platform chemical for the synthesis of a variety of polymers. In this work, Rhodococcus opacus PD630, which is efficient in the assimilation of aromatic compounds, was modified for the first time to accumulate cis,cis-muconate from lignin and lignin-derived aromatics. To achieve efficient genome modification for R. opacus PD630, a markerless gene deletion/insertion system was constructed based on a mutant phenylalanyl-tRNA synthase gene as a counter-selection marker. With the developed gene deletion/insertion system, several R. opacus PD630 mutants were successfully constructed for cis,cis-muconate production from lignin-derived aromatics using catechol and protocatechuate as two key funnel nodes. Results indicated the constructed strains could assimilate at least 15 types of lignin-derived aromatics and real lignin for cis,cis-muconate production. Moreover, both lactase addition and H2SO4 + NaOH combinatorial pretreatment enhanced real lignin valorization to cis,cis-muconate. Ultimately, 1.63 g/L cis,cis-muconate was produced using lignin from corn stover as the substrate by a fed-batch fermentation process. Overall, these results highlight the great potential of using R. opacus as a cell factory for valorizing lignin to cis,cis-muconate and other valuable products.