Background Furfural and acetic acid are the two major inhibitors generated during lignocellulose pretreatment and hydrolysis, would severely inhibit the cell growth, metabolism, and ethanol fermentation efficiency of Zymomonas mobilis. Effective genome shuffling mediated by protoplast electrofusion was developed and then applied to Z. mobilis. Results After two rounds of genome shuffling, 10 different mutants with improved cell growth and ethanol yield in the presence of 5.0 g/L acetic acid and 3.0 g/L furfural were obtained. The two most prominent genome-shuffled strains, 532 and 533, were further investigated along with parental strains in the presence of 7.0 g/L acetic acid and 3.0 g/L furfural. The results showed that mutants 532 and 533 were superior to the parental strain AQ8-1 in the presence of 7.0 g/L acetic acid, with a shorter fermentation time (30 h) and higher productivity than AQ8-1. Mutant 533 exhibited subtle differences from parental strain F34 in the presence of 3.0 g/L furfural. Mutations present in 10 genome-shuffled strains were identified via whole-genome resequencing, and the source of each mutation was identified as either de novo mutation or recombination of the parent genes. Conclusions These results indicate that genome shuffling is an efficient method for enhancing stress tolerance in Z. mobilis. The engineered strains generated in this study could be potential cellulosic ethanol producers in the future.

中文翻译：

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基因组改组增强了运动发酵单胞菌对两种抑制剂的压力耐受性。

背景糠醛和乙酸是木质纤维素预处理和水解过程中产生的两种主要抑制剂，会严重抑制运动发酵单胞菌的细胞生长、代谢和乙醇发酵效率。开发了由原生质体电融合介导的有效基因组改组，然后应用于运动发酵单胞菌。结果经过两轮基因组改组，在5.0 g/L乙酸和3.0 g/L糠醛存在下，获得了10个不同的突变体，其细胞生长和乙醇产量均得到改善。在 7.0 g/L 乙酸和 3.0 g/L 糠醛存在下，与亲本菌株一起进一步研究了两个最突出的基因组改组菌株 532 和 533。结果表明，在乙酸 7.0 g/L 的情况下，突变体 532 和 533 优于亲本菌株 AQ8-1，与 AQ8-1 相比，发酵时间更短（30 小时），产率更高。在 3.0 g/L 糠醛存在下，突变体 533 与亲本菌株 F34 表现出细微差异。通过全基因组重测序鉴定了 10 个基因组改组菌株中存在的突变，每个突变的来源被鉴定为从头突变或亲本基因的重组。结论 这些结果表明基因组改组是提高运动发酵单胞菌胁迫耐受性的有效方法。本研究中产生的工程菌株可能是未来潜在的纤维素乙醇生产商。通过全基因组重测序鉴定了 10 个基因组改组菌株中存在的突变，每个突变的来源被鉴定为从头突变或亲本基因的重组。结论 这些结果表明基因组改组是提高运动发酵单胞菌胁迫耐受性的有效方法。本研究中产生的工程菌株可能是未来潜在的纤维素乙醇生产商。通过全基因组重测序鉴定了 10 个基因组改组菌株中存在的突变，每个突变的来源被鉴定为从头突变或亲本基因的重组。结论 这些结果表明基因组改组是提高运动发酵单胞菌胁迫耐受性的有效方法。本研究中产生的工程菌株可能是未来潜在的纤维素乙醇生产商。