MOLECULAR BIOTECHNOLOGY
·
2016
·Vol. 58
·期 6
·428-440
·
IF 1.752
Yang Yuanyuan,Lin Jinping,Wei Dongzhi
A NADPH-dependent and FMN-containing nitroreductase (Gox0834) from Gluconobacter oxydans was cloned and heterogeneously expressed in Escherichia coli . The purified enzyme existed as a dimer with an apparent molecular mass of about 31.4 kDa. The enzyme displayed broad substrate specificity and reduced a variety of mononitrated, polynitrated, and polycyclic nitroaromatic compounds to the corresponding amino products. The highest activity was observed for the reduction of CB1954 (5-(1-aziridinyl)-2,4-dinitrobenzamide). The enzyme kinetics analysis showed that Gox0834 had relatively low K
m
(54 ± 11 μM) but high k
cat / K
m
value (0.020 s −1 /μM) for CB1954 when compared with known nitroreductases. Nitrobenzene and 2,4,6-trinitrotoluene (TNT) were preferred substrates for this enzyme with specific activity of 11.0 and 8.9 μmol/min/mg, respectively. Gox0834 exhibited a broad temperature optimum of 40–60 °C for the reduction of CB1954 with a pH optimum between 7.5 and 8.5. The purified enzyme was very stable below 37 °C over a broad pH range of 6.0–10.0. These characteristics suggest that the nitroreductase Gox0834 may be a possible candidate for catalyzing prodrug activation, bioremediation, or biocatalytic processes.
研究领域:
微生物学
·
酶学
·
环境科学
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DOI
PubMed
高影响因子
Fermentation-Basel
·
2023
·Vol. 9
·期 3
·286
·
IF 3.7
Hongsen Zhang,Jiahui Jiang,Conghui Quan,Guizhong Zhao,Guotao Mao,Hui Xie,Fengqin Wang,Zhimin Wang,Jian Zhang,Pingping Zhou,Andong Song
Inhibitors from lignocellulosic biomass have become the bottleneck of biorefinery development.Gluconobacter oxydansDSM2003 showed a high performance of inhibitors degradation, which had a short lag time in non-detoxified corn stover hydrolysate and could convert 90% of aldehyde inhibitors to weaker toxic acids. In this study, an aldehyde dehydrogenase geneW826-RS0111485, which plays an important function in the conversion of aldehyde inhibitors inGluconobacter oxydansDSM2003, was identified.W826-RS0111485was found by protein profiling, then a series of enzymatic properties were determined and were heterologously expressed inE. coli. The results indicated that NADP is the most suitable cofactor of the enzyme when aldehyde inhibitor is the substrate, and it had the highest oxidation activity to furfural among several aldehyde inhibitors. Under the optimal reaction conditions (50 °C, pH 7.5), theKmandVmaxof the enzyme under furfural stress were 2.45 and 80.97, respectively, and theKcatwas 232.22 min−1. The biodetoxification performance experiments showed that the recombinantE. colicontaining the target gene completely converted 1 g/L furfural to furoic acid within 8 h, while the controlE. colionly converted 18% furfural within 8 h. It was further demonstrated thatW826-RS0111485played an important role in the detoxification of furfural. The mining of this inhibitor degradation gene could provide a theoretical basis for rational modification of industrial strains to enhance its capacity of inhibitor degradation in the future.Keywords:inhibitors degradation;Gluconobacter oxydans;protein profiling;aldehyde dehydrogenase;furfural
研究领域:
生物技术
·
酶学
·
微生物学
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DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2016
·
IF 4.917
Hongsen Zhang,Gang Liu,Jian Zhang,Jie Bao
High titer gluconic acid and xylonic acid were simultaneously fermented by Gluconobacter oxydans DSM 2003 using corn stover feedstock after dry dilute sulfuric acid pretreatment, biodetoxification and high solids content hydrolysis. Maximum sodium gluconate and xylonate were produced at the titer of 132.46 g/L and 38.86 g/L with the overall yield of 97.12% from glucose and 90.02% from xylose, respectively. The drawbacks of filamentous fungus Aspergillus niger including weak inhibitor tolerance, large pellet formation and no xylose utilization were solved by using the bacterium strain G. oxydans . The obtained sodium gluconate/xylonate product was highly competitive as cement retarder additive to the commercial product from corn feedstock. The techno-economic analysis (TEA) based on the Aspen Plus modeling was performed and the minimum sodium gluconate/xylonate product selling price (MGSP) was calculated as $0.404/kg. This study provided a practical and economic competitive process of lignocellulose utilization for production of value-added biobased chemicals.
研究领域:
生物工程
·
可再生资源利用
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DOI
PubMed
高影响因子
PROCESS BIOCHEMISTRY
·
2020
·
IF 2.952
Xuelian Zhou,Yi Shen,Yong Xu,Venkatesh Balan
2-Keto- d -gluconic acid (2-KGA) is a high-value-added product from lignocellulosic straw-based biorefining process obtained via cell catalysis using Gluconobacter oxydans ( G. oxydans ); nonetheless, the economical production has some limitations because of the formation of undesirable mixture products of keto-gluconic acid from glucose. In this study, it was demonstrated that pulse addition of hydrogen peroxide (H 2 O 2 ) to synthetic media was beneficial to improve the conversion rate of glucose to 2-KGA by 1.47-fold in G. oxydans . Moreover, some lignocellulosic degradation compounds served as substitute and played the role of H 2 O 2 on corn stover hydrolysate for the production of 2-KGA. By conducting qRT-PCR analysis, eight dehydrogenase genes were identified in G. oxydans , which were responsible for regulating 2-KGA production. Moreover, most of the identified genes were found to produce membrane-bound glucose dehydrogenase and gluconate 2-dehydrogenase, and were up-regulated by adding H 2 O 2 or degradation compounds. These up-regulated genes could be responsible for directing cell catalysis of glucose to 2-KGA in G. oxydans .
研究领域:
生物化学
·
微生物学
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DOI
高影响因子
BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2023
·Vol. 46
·期 4
·589-597
·
IF 3.8
Jiang Wenfei,Dai Lin,Tan Xin,Zhou Xin,Xu Yong
Pre-hydrolysate liquor, as an inevitable by-product, contains a large amount of xylose, and is therefore an inexpensive feedstock that can be upgraded to value-added chemical xylonic acid. However, inhibitors, simultaneously formed in lignocellulose pretreatment process, are regarded as the major obstacle for effectively bio-converting xylose in pre-hydrolysate into xylonic acid. In this study, Gluconobacter oxydans , with highly selective and efficient, was employed for xylonic acid production; the impacts of five typical toxic inhibitory compounds on xylonic acid productivity and the activity of the membrane-bound dehydrogenase were evaluated. The results revealed that the inhibitors showed different degrees of influence toward xylonic acid production, and the order of inhibitory effect for acidic inhibitors was formic acid > acetic acid > levulinic acid; the inhibitory effect of aldehyde inhibitors was furfural > 5-hydroxymethyl-furfural. This study provides an important basis of metabolic modification and detoxification process for enhancing inhibitor tolerance and xylonic acid productivity. Graphical abstract
研究领域:
生物工程
·
发酵工程
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DOI
PubMed
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Yuqinxin Xie,Dongzhi Wei,Jinping Lin
(4 S )-3-[(5 S )-5-(4-fluorophenyl)-5‑hydroxy-valyl]-4-phenyl-1,3-oxazacyclopentane-2-one (( S )-Fop alcohol) is a key chiral intermediate for the synthesis of ezetimibe, and could be synthesized via asymmetric reduction of ( S )-4-phenyl-3-[5-(4-fluorophenyl)-5-oxopentanoyl]-2-oxazolidione (Fop dione). However, discovering and engineering of ketoreductases toward bulky-bulky (diaryl) ketones is still challenging. Previously, we identified an alcohol dehydrogenase Gox0525 from Gluconobacter oxydans DSM2343 which possessed strict diastereoselectivity ( d.e. value > 99%) but low activity toward Fop dione. In this study, a semi-rational design based on the focused rational iterative site-specific mutagenesis (FRISM) based on site-directed saturation mutagenesis was performed to improve the catalytic efficiency of Gox0525. The variant M4 (Y92G/P93M/Y94P/L151V) shows a 64-fold enhanced catalytic efficiency ( K cat / K m ) and 47-fold in specific activity compared with the wild type Gox0525. Engineered Escherichia coli cells co-expressing the variant M4 and glucose dehydrogenase from Bacillus subtilis (BsGDH) for NADPH regeneration were employed as biocatalysts for gram-scale reaction of Fop dione. As a result,95 mM (33.76 g/L) Fop dione was completely transformed within 4 h, affording ( S )-Fop alcohol with > 99% d.e. value, the yield of 96%, and the space-time yield of 195.6 g/L/d.
研究领域:
生物技术
·
生物化学
·
药物化学
·
酶学
·
化工
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DOI
高影响因子
BIOCHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 3.978
Xia Hua,XinLu Liu,Jian Han,Yong Xu
Acetate (Ac - ) is a critical factor for the biochemical regulation of G. oxydans which has widely applied in food industry . Herein, a basic scheme to determine the effect of Ac - concentrations on G. oxydans was established. Low concentrations of Ac - were beneficial in improving the whole-cell catalysis for sorbose bioconversion from 39.23 g/L to 53.79 g/L. From the enzyme activity test results showed that low Ac - concentration promoted enzyme activity by about 7% and increased the relative transcription level of membrane-bound sorbitol dehydrogenase (mSLD) by 2–3 times. The contradiction between the enhancement of relative transcription level and the inhibition of cell-growth and bio-conversion efficiency by high Ac - concentration was elucidated through the carbohydrate metabolism and adenosine triphosphate (ATP) assays. Finally, the bioprocess regulation of G. oxydans was determined through multi-dimensional comprehensive explorations. This study provides an increased understanding of G. oxydans and lays a solid theoretical foundation for its use as a food industrial bio-catalyst, especially to lignocellulosic hydrolysates.
研究领域:
生物化学
·
生物技术
·
食品科学
·
微生物学
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DOI
高影响因子
Biotechnology for Biofuels and Bioproducts
·
2022
·Vol. 15
·期 1
·1-10
·
IF 0
Hua Xia,Zhang ChenHui,Han Jian,Xu Yong
Background Hydroxyl acid is an important platform chemical that covers many industrial applications due to its dual functional modules. At present, the traditional technology for hydroxyl acid production mainly adopts the petroleum route with benzene, cyclohexane, butadiene and other non-renewable resources as raw materials which violates the development law of green chemistry. Conversely, it is well-known that biotechnology and bioengineering techniques possess several advantages over chemical methods, such as moderate reaction conditions, high chemical selectivity, and environmental-friendly. However, compared with chemical engineering, there are still some major obstacles in the industrial application of biotechnology. The critical issue of the competitiveness between bioengineering and chemical engineering is products titer and volume productivity. Therefore, based on the importance of hydroxyl acids in many fields, exploring a clean, practical and environmental-friendly preparation process of the hydroxyl acids is the core purpose of this study. Results To obtain high-purity hydroxyl acid, a microbiological regulation for its bioproduction by Gluconobacter oxydans was constructed. In the study, we found a critical point of chain length determine the end-products. Gluconobacter oxydans catalyzed diols with chain length ≤ 4, forming hydroxyl acids, and converting 1,5-pentylene glycol and 1,6-hexylene glycol to diacids. Based on this principle, we successfully synthesized 75.3 g/L glycolic acid, 83.2 g/L 3-hydroxypropionic acid, and 94.3 g/L 4-hydroxybutyric acid within 48 h. Furthermore, we directionally controlled the products of C5/C6 diols by adjusting pH, resulting in 102.3 g/L 5‑hydroxyvaleric acid and 48.8 g/L 6-hydroxycaproic acid instead of diacids. Combining pH regulation and cell-recycling technology in sealed-oxygen supply bioreactor, we prepared 271.4 g 5‑hydroxyvaleric acid and 129.4 g 6-hydroxycaproic acid in 6 rounds. Conclusions In this study, a green scheme of employing G. oxydans as biocatalyst for superior-quality hydroxyl acids (C2–C6) production is raised up. The proposed strategy commendably demonstrated a novel technology with simple pH regulation for high-value production of hydroxyl acids via green bioprocess developments.
研究领域:
生物化学
·
绿色化学
·
生物工程
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DOI
PubMed
BIOTECHNOLOGY AND BIOENGINEERING
·
2026
·
IF 3.9
Wei Hu,Biying Guo,Yating Hu,Yong Xu,Xia Hua
Increasing the biotransformation temperature to balance the conditions of saccharification (50°C–60°C) is a crucial measure for intensifying bioprocess competitiveness. The study established a glycerol-assisted thermal strategy to mitigate the damage caused by high temperature on Gluconobacter oxydans . This approach successfully improved bioconversion performance by simultaneously overcoming limitations in catalytic efficiency and cell recovery. With 15 mmol/L glycerol assistance, the proportion of live cells remained at 75.9% after whole-cell catalysis at 37°C for 40 h. Moreover, 570.2 g xylonic acid was accumulated from pure xylose with the average volumetric productivity per round of 14.3 g/L/h, which was 14.5% and 19.6% higher than that of 30°C and 37°C without assistance. Additionally, to validate its practicality, this strategy was further applied to corncob hydrolysate, resulting 216.8 g xylonic acid from 1000 g corncob with the productivity of 4.1 g/h. This work presented an economically viable approach for lignocellulosic biorefinery and offers insights for its further development.
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DOI
PubMed
高影响因子
AICHE JOURNAL
·
2022
·Vol. 69
·期 3
·e18005
·
IF 4.167
Xia Hua,Jian Han,Xin Zhou,Yong Xu
Oxygen, as a terminal electron acceptor, is an essential substrate in the aerobic bio-oxidation process, affecting bacterial vitality and bio-oxidation performance. In this study, a newfangled platform biotechnology of sealed-oxygen supply bioreactor (SOS-BR) was developed by improving gas pressure to significantly intensify oxygen transfer rate to resolve the formidable barriers of aerobic catalysis. In virtue of SOS-BR, the bio-productivity was greatly improved for three representative substrates (xylose, furfural, and glycerol) bio-oxidation with the whole-cell catalysis of Gluconobacter oxydans . The determination of oxygen transfer coefficient ( K L α ) established an upgraded theoretical dynamic model for gas pressure intensification biosystem. Additionally, viscosity measurement and combined pressure control strategy explained the inflection point phenomenon of productivity and confirmed the intensify mechanism. The smart strategy of significantly intensifying oxygen transfer provided insightful ideas for overcoming the stubborn obstacle of obligate aerobic catalysis, and further promoted the development and industrial practicability of bio-oxidation.
研究领域:
生物工程
·
微生物学
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DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2017
·
IF 3.154
Xingxing Zou,Jinping Lin,Xinlei Mao,Shengyun Zhao,Yuhong Ren
L-erythrose, a rare aldotetrose, possesses various pharmacological activities. However, efficient L-erythrose production is challenging. Currently, L-erythrose is produced by a two-step fermentation process from erythritol. Here, we describe a novel strategy for the production of L-erythrose in Gluconobacter oxydans (G. oxydans) by localizing the assembly of L-ribose isomerase (L-RI) to membrane-bound sorbitol dehydrogenase (SDH) via the protein–peptide interactions of the PDZ domain and PDZ ligand. To demonstrate this self-assembly, green fluorescent protein (GFP) replaced L-RI and its movement to membrane-bound SDH was observed by fluorescence microscopy. The final L-erythrose production was improved to 23.5 g/L with the stepwise metabolic engineering of G. oxydans, which was 1.4-fold higher than that obtained using coexpression of SDH and L-RI in G. oxydans. This self-assembly strategy shows remarkable potential for further improvement of L-erythrose production.
研究领域:
生物化学
·
生物技术
·
微生物学
·
代谢工程
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DOI
PubMed
高影响因子
BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2022
·Vol. 46
·期 1
·15-23
·
IF 3.434
Ding Chenrong,Xu Chaozhong,He Tao,Liu Xu,Zhu Yafei,Sun Liqun,Ouyang Jia,Gu Xiaoli
In this work, the effect of activated carbon particles on the production of xylonic acid from xylose by Gluconobacter oxydans in a stirred tank bioreactor was investigated. The enhancement of the oxygen transfer coefficient by activated carbon particles was experimentally evaluated under different solids volume fractions, agitation and aeration rates conditions. The experimental conditions optimized by response surface methodology (agitation speed 800 rpm, aeration rate 7 L min −1 , and activated carbon 0.002%) showed a maximum oxygen transfer coefficient of 520.7 h −1 , 40.4% higher than the control runs without activated carbon particles. Under the maximum oxygen transfer coefficient condition, the xylonic acid titer reached 108.2 g/L with a volumetric productivity of 13.53 g L −1 h −1 and a specific productivity of 6.52 g/g x /h. In conclusion, the addition of activated carbon particles effectively enhanced the oxygen mass transfer rate. These results demonstrate that activated carbon particles enhanced cultivation for xylonic acid production an inexpensive and attractive alternative.
研究领域:
生物技术
·
化学工程
·
发酵科学
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）