Effects of Inhibitors on the Transcriptional Profiling of Gluconobater oxydans NL71 Genes after Biooxidation of Xylose into Xylonate

Miao, Yuanyuan; Shen, Yi; Xu, Yong

doi:10.3389/fmicb.2017.00716

Cited by 17 publications

(5 citation statements)

References 44 publications

(52 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A decomposition intermediate of hexoses is 5-hydroxymethylfurfural (HMF) [ 78 ], mainly at pH values below 7 [ 82 ]. HMF is also a by-product of lignocellulosic pre-treatment and a well-known inhibitor of microorganisms [ 51 , 52 , 83 – 86 ]. Using biomass hydrolysates as substrates for the cultivation of G. oxydans showed inhibitory effects, e.g.…”

Section: Resultsmentioning

confidence: 99%

Highly efficient fermentation of 5-keto-d-fructose with Gluconobacter oxydans at different scales

et al. 2022

View full text Add to dashboard Cite

Background The global market for sweeteners is increasing, and the food industry is constantly looking for new low-caloric sweeteners. The natural sweetener 5-keto-d-fructose is one such candidate. 5-Keto-d-fructose has a similar sweet taste quality as fructose. Developing a highly efficient 5-keto-d-fructose production process is key to being competitive with established sweeteners. Hence, the 5-keto-d-fructose production process was optimised regarding titre, yield, and productivity. Results For production of 5-keto-d-fructose with G. oxydans 621H ΔhsdR pBBR1-p264-fdhSCL-ST an extended-batch fermentation was conducted. During fructose feeding, a decreasing respiratory activity occurred, despite sufficient carbon supply. Oxygen and second substrate limitation could be excluded as reasons for the decreasing respiration. It was demonstrated that a short period of oxygen limitation has no significant influence on 5-keto-d-fructose production, showing the robustness of this process. Increasing the medium concentration increased initial biomass formation. Applying a fructose feeding solution with a concentration of approx. 1200 g/L, a titre of 545 g/L 5-keto-d-fructose was reached. The yield was with 0.98 g5-keto-d-fructose/gfructose close to the theoretical maximum. A 1200 g/L fructose solution has a viscosity of 450 mPa∙s at a temperature of 55 °C. Hence, the solution itself and the whole peripheral feeding system need to be heated, to apply such a highly concentrated feeding solution. Thermal treatment of highly concentrated fructose solutions led to the formation of 5-hydroxymethylfurfural, which inhibited the 5-keto-d-fructose production. Therefore, fructose solutions were only heated to about 100 °C for approx. 10 min. An alternative feeding strategy was investigated using solid fructose cubes, reaching the highest productivities above 10 g5-keto-d-fructose/L/h during feeding. Moreover, the scale-up of the 5-keto-d-fructose production to a 150 L pressurised fermenter was successfully demonstrated using liquid fructose solutions (745 g/L). Conclusion We optimised the 5-keto-d-fructose production process and successfully increased titre, yield and productivity. By using solid fructose, we presented a second feeding strategy, which can be of great interest for further scale-up experiments. A first scale-up of this process was performed, showing the possibility for an industrial production of 5-keto-d-fructose.

show abstract

Section: Resultsmentioning

confidence: 99%

Highly efficient fermentation of 5-keto-d-fructose with Gluconobacter oxydans at different scales

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Moreover, these inhibitors are likely to become more toxic to microorganisms because they induce a cumulative or synergistic effect despite their very low hydrolysate contents. The critical inhibitory impact of p-hydroxybenzaldehyde, formic acid, levulinic acid, and furfural on XA production by G. oxydans was reported [20,27,28]. Genetic engineering and the adaptive evolution of microorganisms are usually employed to effectively improve microbe resistance and XA production from hydrolysates [27,29].…”

Section: Open Accessmentioning

confidence: 99%

Overexpression of mGDH in Gluconobacter oxydans to improve d-xylonic acid production from corn stover hydrolysate

et al. 2022

View full text Add to dashboard Cite

Background d-Xylonic acid is a versatile platform chemical with broad potential applications as a water reducer and disperser for cement and as a precursor for 1,4-butanediol and 1,2,4-tributantriol. Microbial production of d-xylonic acid with bacteria such as Gluconobacter oxydans from inexpensive lignocellulosic feedstock is generally regarded as one of the most promising and cost-effective methods for industrial production. However, high substrate concentrations and hydrolysate inhibitors reduce xylonic acid productivity. Results The d-xylonic acid productivity of G. oxydans DSM2003 was improved by overexpressing the mGDH gene, which encodes membrane-bound glucose dehydrogenase. Using the mutated plasmids based on pBBR1MCS-5 in our previous work, the recombinant strain G. oxydans/pBBR-R3510-mGDH was obtained with a significant improvement in d-xylonic acid production and a strengthened tolerance to hydrolysate inhibitors. The fed-batch biotransformation of d-xylose by this recombinant strain reached a high titer (588.7 g/L), yield (99.4%), and volumetric productivity (8.66 g/L/h). Moreover, up to 246.4 g/L d-xylonic acid was produced directly from corn stover hydrolysate without detoxification at a yield of 98.9% and volumetric productivity of 11.2 g/L/h. In addition, G. oxydans/pBBR-R3510-mGDH exhibited a strong tolerance to typical inhibitors, i.e., formic acid, furfural, and 5-hydroxymethylfurfural. Conclusion Through overexpressing mgdh in G. oxydans, we obtained the recombinant strain G. oxydans/pBBR-R3510-mGDH, and it was capable of efficiently producing xylonic acid from corn stover hydrolysate under high inhibitor concentrations. The high d-xylonic acid productivity of G. oxydans/pBBR-R3510-mGDH made it an attractive choice for biotechnological production.

show abstract

“…RNA was extracted as described in the section RNA-Seq analysis. Real-time quantitative polymerase chain reaction (qRT-PCR) was performed using SYBR Premix ExTaq Kit (TaKaRa, Japan) in ABI StepOnePlus TM Real-Time PCR System (Applied Biosystems, America), as reported previously (Miao et al, 2017). The primers for qRT-PCR were listed in Table 1.…”

Section: Qrt-pcrmentioning

confidence: 99%

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

Liu

Wang²,

Xiao³

et al. 2022

Front. Microbiol.

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Effects of Inhibitors on the Transcriptional Profiling of Gluconobater oxydans NL71 Genes after Biooxidation of Xylose into Xylonate

Cited by 17 publications

References 44 publications

Highly efficient fermentation of 5-keto-d-fructose with Gluconobacter oxydans at different scales

Highly efficient fermentation of 5-keto-d-fructose with Gluconobacter oxydans at different scales

Overexpression of mGDH in Gluconobacter oxydans to improve d-xylonic acid production from corn stover hydrolysate

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

Contact Info

Product

Resources

About