Enhancement of solvent tolerance and economical bioethanol production by modulated sigma 54 expression of Pseudomonas putida

Sigma 54 was modulated in Pseudomonas putida to enhance solvent tolerance to increase Pseudomonas putida solvent production. Three modified P. putida S12 strains (ST-54A, B, and C) were produced by knocking out the endogenous rpoN encoding gene (rpoN) at position σ54 and fusing it with three different ribosome-binding site (RBS) sequences with various translation-initiation rates. For 1-h shock testing and 24-h tolerance tests, these strains were exposed to ethanol, n-butanol, or isobutanol at various RBS-based starting translation rates. Under every treatment situation, modified strains outlived the wild-type strain. It was discovered that the concentration of sigma 54 proteins was correlated with the level of solvent tolerance by fusing rpoN with increased green fluorescent protein genes. Genes involved in ethanol synthesis were inserted into the modified strains of P. putida S12 and its wild-type counterpart. This study discovered a link between sigma 54 expression and ethanol yields. All three modified strains exhibited significantly higher ethanol production than the wild-type strain, and ST-54A exhibited the highest ethanol production of 0.79%. This is a crucial stage in the development of biocatalytic cells that can be produced economically.