Zmo0994, a novel LEA-like protein from Zymomonas mobilis, increases multi-Abiotic stress tolerance in Escherichia coli

Background: Pretreatment processes and subsequent enzymatic hydrolysis are prerequisites to utilize lignocellulosic sugar for fermentation. However, the resulting hydrolysate frequently hinders fermentation processes due to the presence of inhibitors and toxic products (e.g., ethanol). Thus, it is crucial to develop robust microbes conferring multi-stress tolerance. Results: Zmo0994, a functionally uncharacterized protein from Zymomonas mobilis, was identified and characterized for the first time. A major effect of Zmo0994 was a significant enhancement in the tolerance to abiotic stresses such as ethanol, furfural, 5′-hydroxymethylfurfural and high temperature, when expressed in Escherichia coli. Through transcriptome analysis and in vivo experiments, the cellular mechanism of this protein was revealed as due to its ability to trigger genes, involved in aerobic respiration for ATP synthesis. Conclusions: These findings have significant implications that might lead to the development of robust microbes for the highly efficient industrial fermentation processes.