Shin Minhye, Park Heeyoung, Kim Sooah, Oh Eun Joong, Jeong Deokyeol, Florencia Clarissa, Kim Kyoung Heon, Jin Yong-Su, Kim Soo Rin
Department of Agricultural Biotechnology, Research Institute of Agriculture and Life Science, Seoul National University, Seoul, South Korea.
School of Food Science and Biotechnology, Kyungpook National University, Daegu, South Korea.
Front Bioeng Biotechnol. 2021 Mar 25;9:654177. doi: 10.3389/fbioe.2021.654177. eCollection 2021.
Being a microbial host for lignocellulosic biofuel production, needs to be engineered to express a heterologous xylose pathway; however, it has been challenging to optimize the engineered strain for efficient and rapid fermentation of xylose. Deletion of (Δ) has been reported to be a crucial genetic perturbation in improving xylose fermentation. A confirmed mechanism of the Δ effect on xylose fermentation is that the Δ transcriptionally activates the genes in the non-oxidative pentose phosphate pathway (PPP). In the current study, we found a couple of engineered strains, of which phenotypes were not affected by Δ (Δ-negative), among many others we examined. Genome resequencing of the Δ-negative strains revealed that a loss-of-function mutation in was responsible for the phenotype. Gcr2 is a global transcriptional factor involved in glucose metabolism. The results of RNA-seq confirmed that the deletion of (Δ) led to the upregulation of PPP genes as well as downregulation of glycolytic genes, and changes were more significant under xylose conditions than those under glucose conditions. Although there was no synergistic effect between Δ and Δ in improving xylose fermentation, these results suggested that is a novel knockout target in improving lignocellulosic ethanol production.
作为木质纤维素生物燃料生产的微生物宿主，需要进行工程改造以表达异源木糖途径；然而，优化工程菌株以实现高效快速的木糖发酵一直具有挑战性。据报道，删除（Δ）是改善木糖发酵的关键基因扰动。Δ对木糖发酵影响的一个已证实机制是，Δ转录激活非氧化戊糖磷酸途径（PPP）中的基因。在本研究中，我们在许多检测的菌株中发现了一些工程菌株，其表型不受Δ（Δ阴性）影响。对Δ阴性菌株的基因组重测序表明，中的功能丧失突变是造成该表型的原因。Gcr2是一种参与葡萄糖代谢的全局转录因子。RNA测序结果证实，删除（Δ）导致PPP基因上调以及糖酵解基因下调，且在木糖条件下的变化比在葡萄糖条件下更显著。尽管在改善木糖发酵方面，Δ和Δ之间没有协同效应，但这些结果表明，是改善木质纤维素乙醇生产的一个新的敲除靶点。
