The consequence of an additional NADH dehydrogenase paralog on the growth of Gluconobacter oxydans DSM3504

Abstract

Acetic acid bacteria such as Gluconobacter oxydans are used in several biotechnological processes due to their ability to perform rapid incomplete regio- and stereo-selective oxidations of a great variety of carbohydrates, alcohols, and related compounds by their membrane-bound dehydrogenases. In order to understand the growth physiology of industrial strains such as G. oxydans ATCC 621H that has high substrate oxidation rates but poor growth yields, we compared its genome sequence to the genome sequence of strain DSM 3504 that reaches an almost three times higher optical density. Although the genome sequences are very similar, DSM 3504 has additional copies of genes that are absent from ATCC 621H. Most importantly, strain DSM 3504 contains an additional type II NADH dehydrogenase (ndh) gene and an additional triosephosphate isomerase (tpi) gene. We deleted these additional paralogs from DSM 3504, overexpressed NADH dehydrogenase in ATCC 621H, and monitored biomass and the concentration of the representative cell components as well as O2 and CO2 transfer rates in growth experiments on mannitol. The data revealed a clear competition of membrane-bound dehydrogenases and NADH dehydrogenase for channeling electrons in the electron transport chain of Gluconobacter and an important role of the additional NADH dehydrogenase for increased growth yields. The less active the NADH dehydrogenase is, the more active is the membrane-bound polyol dehydrogenase. These results were confirmed by introducing additional ndh genes via plasmid pAJ78 in strain ATCC 621H, which leads to a marked increase of the growth rate.

Nectar microbes can reduce secondary metabolites in nectar and alter effects on nectar consumption by pollinators

“…The specific mechanism of degradation was not examined, but the closely related bacterium Gluconobacter oxydans expresses β‐glucosidase (Kostner et al. ), which can initiate the degradation of glycosides, including aucubin. These effects on the concentration or toxicity of secondary chemicals may extend to influence pollinator foraging (Detzel and Wink , Kessler and Baldwin , Köhler et al.…”

“…reduced the concentration of aucubin to the greatest extent of any of the microbes tested. The specific mechanism of degradation was not examined, but the closely related bacterium Gluconobacter oxydans expresses βglucosidase (Kostner et al 2015), which can initiate the degradation of glycosides, including aucubin. These effects on the concentration or toxicity of secondary chemicals may extend to influence pollinator foraging (Detzel and Wink 1993, Kessler and Baldwin 2006, Köhler et al 2012, which is largely dependent on concentration (Singaravelan et al 2005, Wright et al 2013, Tiedeken et al 2014.…”

A single membrane-bound enzyme catalyzes the conversion of 2,5-diketo-d-gluconate to 4-keto-d-arabonate in d-glucose oxidative fermentation by Gluconobacter oxydans NBRC 3292

“…Therefore, we performed gene cloning to obtain further knowledge of the enzyme. The genomic sequence of G. oxydans DSM 3504 that is the identical to the G. oxydans NBRC 3292 strain has been determined and available to the public; 11) therefore, the N-terminal amino acid sequence of natural 4KAS purified from G. oxydans NBRC 3292 was determined and followed by the NCBI BLAST ® search, which predicted as a hypothetical GLS_c04240 protein comprising 398 amino acid residues translated from an open reading frame (ORF), corresponding to the region from 448855 to 450051 complement in accession No. CP004373 with 100% identity.…”

Global mRNA decay and 23S rRNA fragmentation in Gluconobacter oxydans 621H

“…To overcome these hindrances, metabolic engineering was performed to complete the TCA cycle by introducing heterologous genes for succinate dehydrogenase and succinyl-CoA synthetase into the genome with simultaneous deletion of the genes for the membrane-bound and soluble glucose dehydrogenase, thus abolishing periplasmic and cytoplasmic glucose oxidation [ 12 , 13 ]. Furthermore, the NADH oxidation capacity was increased by introducing an additional NADH dehydrogenase gene [ 14 ]. These steps led to an increase of the biomass yield on glucose by up to 60%, thereby reducing the costs for biomass formation.…”