Osmotic stress tolerance and transcriptome analysis of Gluconobacter oxydans to extra-high titers of glucose

Abstract

Gluconobacter oxydans has been widely acknowledged as an ideal strain for industrial bio-oxidations with fantastic yield and productivity. Even 600 g/L xylose can be catalyzed efficiently in a sealed and compressed oxygen-supplying bioreactor. Therefore, the present study seeks to explore the osmotic stress tolerance against extra-high titer of representative lignocellulosic sugars like glucose. Gluconobacter oxydans can well adapted and fermented with initial 600 g/L glucose, exhibiting the highest bio-tolerance in prokaryotic strains and the comparability to the eukaryotic strain of Saccharomyces cerevisiae. 1,432 differentially expressed genes corresponding to osmotic pressure are detected through transcriptome analysis, involving several genes related to the probable compatible solutes (trehalose and arginine). Gluconobacter oxydans obtains more energy by enhancing the substrate-level phosphorylation, resulting in the increased glucose consumption rate after fermentation adaption phase. This study will provide insights into further investigation of biological tolerance and response to extra-high titers of glucose of G. oxydans.

Systemic metabolic engineering of Enterobacter aerogenes for efficient 2,3-butanediol production

“…Among them, the introduction of regulatory factors is a useful strategy to improve tolerance to target compounds even in the face of unknown toxicity mechanisms. To date, there are various stress threats during microbial fermentation, such as acid stress (Yao et al 2022 ), ethanol stress (de Moura Ferreira et al 2022 ), high osmotic stress (Liu et al 2022 ), and high-temperature stress (Phong et al 2022 ). D. radiodurans is one of the most stress-tolerant species and has been described as “the hardiest bacteria on Earth.” Many studies have demonstrated that the introduction of deinococcal response regulators, such as IrrE and DR1558, into the two-component system of a heterologous host can enhance stress tolerance, including radiation tolerance, osmotolerance, salt tolerance, alcohol tolerance, and acid tolerance (Guo et al 2017 ; Park et al 2019 ; Park et al 2020a , b ).…”

Cascading and precise regulation of the selective bio-production of 2- or 5-ketogluconic acid from glucose with whole-cell catalysis technology

“…1. 30,31 G. oxydans has two distinct glucose oxidase systems. The first is located in the cytoplasm, and involves NADP-dependent glucose dehydrogenase (GDH), NAD-dependent gluconate 5-oxidoreductase, and NADPH-dependent 2-ketogluconate reductase.…”