Journal of Environmental Chemical Engineering
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2025
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IF 7.2
Teng-Fei Ma,Hong-Xi Ma,Chong-Yang Xing,Hui-Min Fu,Yu Shen,You-Peng Chen,Xiang-Yang Wei
This study combines physiological and proteomic analyses to explore the silver nanoparticles (Ag NPs) induced stress response and resistance mechanisms in the aerobic denitrifying Enterobacter cloacae strain HNR (strain HNR). Results demonstrated concentration-dependent inhibition: at 0.30 mM Ag NPs, bacterial growth (OD 600 ) decreased to 79.7 % of the control, while nitrate removal efficiency dropped to 52.4 %, accompanied by a 6.4-fold increase in nitrite accumulation. Activities of nitrate reductase and nitrite reductase were reduced to 34.3 % and 41.6 %, respectively. Ag NPs also compromised motility, induced oxidative stress (33.11 % rise in intracellular reactive oxygen species), and disrupted membrane integrity (10.4 % lactate dehydrogenase release). Conversely, extracellular polymeric substances (EPS) production surged by 25.6 % under low Ag NPs (0.01 mM), primarily driven by polysaccharide synthesis (55.5 % increase). Proteomics revealed 1987 differentially expressed proteins (978 upregulated, 1009 downregulated). Downregulated pathways (DNA repair, ribosome biosynthesis, glycerophospholipid metabolism, ABC transporters, oxidative phosphorylation, etc.) indicated that Ag NPs disrupted bacterial genome stability, inhibit synthesis of protein, cell membrane, and interfered with material transport and energy production. In response, strain HNR upregulated the sulfur relay system, tyrosine metabolism, and pentose and glucuronate interconversions to combat oxidative stress and energy metabolism inhibition. Additionally, strain HNR increased EPS production and cell surface positive electroactivity by upregulating the starch and sucrose metabolism and the cationic antimicrobial peptide resistance pathways to counteract the adsorption and contact of Ag NPs and silver ion. These findings will guide improvements in aerobic denitrification processes in NP-polluted aquatic environments and facilitate the broader application of aerobic denitrification technologies.
研究领域:
微生物学
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环境科学
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分子生物学
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DOI
高影响因子
Cell Discovery
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2021
·Vol. 7
·期 1
·1-12
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IF 10.849
Meng Wensi,Zhang Lijie,Cao Menghao,Zhang Yongjia,Zhang Yipeng,Li Ping,Kang Zhaoqi,Guo Shiting,Xu Ping,Ma Cuiqing,Gao Chao
Overflow metabolism-caused acetate accumulation is a major problem that restricts industrial applications of various bacteria. 2,3-Butanediol (2,3-BD) synthesis in microorganisms is an ancient metabolic process with unidentified functions. We demonstrate here that acetate increases and then decreases during the growth of a bacterium Enterobacter cloacae subsp. dissolvens SDM. Both bifunctional acetaldehyde/ethanol dehydrogenase AdhE-catalyzed ethanol production and acetate-induced 2,3-BD biosynthesis are indispensable for the elimination of acetate generated during overflow metabolism. 2,3-BD biosynthesis from glucose supplies NADH required for acetate elimination via AdhE-catalyzed ethanol production. The coupling strategy involving 2,3-BD biosynthesis and ethanol production is widely distributed in bacteria and is important for toxic acetate elimination. Finally, we realized the co-production of ethanol and acetoin from chitin, the second most abundant natural biopolymer whose catabolism involves inevitable acetate production through the coupling acetate elimination strategy. The synthesis of a non-toxic chemical such as 2,3-BD may be viewed as a unique overflow metabolism with desirable metabolic functions.
研究领域:
微生物学
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代谢工程
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产品关联
DOI
PubMed
高影响因子
BIOCHEMICAL ENGINEERING JOURNAL
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2025
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IF 3.8
Xinying Sun,Wei Xiao,Mengying Wu,Fuqiang Liu,Jiaxin Li,Lei Liu,Jing Wu,Keke Cheng,Jianan Zhang
Microbial fermentation technology has advanced rapidly in the field of green chemical production, showcasing broad application prospects. However, current techniques still face challenges such as low carbon utilization efficiency and excessive accumulation of by-products. Additionally, during the fermentation process, carbon sources are released in the form of CO₂, leading to significant carbon loss. In this study, Enterobacter cloacae CICC 10011 was metabolically engineered to achieve the co-production of 2,3-butanediol (2,3-BDO) and lactic acid, while reducing carbon dioxide emissions and improving carbon utilization. By knocking out key genes ( pflB and iclR ), the pathways for the formation of by-products such as formate, acetate, and ethanol were attenuated, thereby optimizing carbon flux toward the target products. The results showed that under optimal fermentation conditions (aeration rate of 0.4 vvm, pH 6.5, temperature 35 °C), the double-gene deletion strain ECΔpflBΔiclR achieved lactic acid and 2,3-BDO (mixture of stereoisomers) concentrations of 51.03 g/L and 10.44 g/L, respectively, with a total target product yield of 1.76 mol/mol. Compared to the wild-type strain, the production of by-products succinate, acetate, and ethanol was reduced by 70.04 %, 47.10 %, and 89.76 %, respectively. Additionally, CO₂ emissions were reduced by 68.92 %, and carbon conversion efficiency improved by 116.16 %. This strategy provides a novel approach for carbon emission reduction and the co-production of high-value chemicals in fermentation processes.
研究领域:
微生物学
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代谢工程
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工业生物技术
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发酵工程
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绿色化学
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生物制造
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碳代谢
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产品关联
DOI
高影响因子
RSC Advances
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2015
·Vol. 6
·期 2
·1279-1287
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IF 3.84
Xuan Zhang,Jun Zhou,Chundan Zhang,Dijun Zhang,Xiurong Su
To establish the rapid detection of Enterobacter cloacae in food, immunomagnetic beads were prepared by coupling an anti-E. cloacae polyclonal antibody with magnetic beads. An immunochromatographic test strip was composited with an anti-E. cloacae monoclonal antibody marked by colloidal gold as the detection antibody, anti-E. cloacae polyclonal antibody as the test line, and donkey anti-mouse IgG secondary antibody as the control line. Immunomagnetic separation was combined with a colloidal gold-based immunochromatographic assay for the rapid detection of E. cloacae. The results showed that 102 CFU mL−1 E. cloacae could be detected using the immunochromatographic test strip after immunomagnetic separation. The sensitivity was 10 times higher than direct detection with an immunochromatographic test strip. With the immunochromatographic test strip, water samples spiked with E. cloacae yielded a negative result, whereas E. cloacae yielded a positive result with immunomagnetic separation. The proposed method enhances the rapid detection of E. cloacae in food.
研究领域:
食品科学
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微生物学
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产品关联
DOI
高影响因子
Frontiers of Environmental Science & Engineering
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2025
·Vol. 19
·期 10
·1-10
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IF 6.4
Zhang Ting,Yang Zhongwei,Li Haibei,Li Hui,Yang Yidi,Chen Tianjiao,Zhou Shuqing,Shi Danyang,Yang Dong,Li Junwen,Jin Min
The presence of the Enterobacter cloacae complex (ECC) in natural water bodies poses potential public health risks because these bacteria can enter humans from the environment within the “One Health” framework. Nevertheless, there is a notable deficiency in the isolation and knowledge of carbapenem- and polymyxin-resistant ECC strains from natural water bodies. In this research, 48 ECC strains were isolated from natural water bodies. Of these, eight strains were resistant to carbapenems (imipenem) and polymyxins (polymyxin B and colistin sulfate) and were classified as multi-locus sequence typing 13. Comparative genomic analysis identified bla CMY-63 , pmrE , pmrF , and various efflux pump genes as key genetic determinants of co-resistance to carbapenems and polymyxins. Notably, these strains exhibited relatively high virulence, with cell death rates ranging from 57% to 84%. They also exhibited virulence against Galleria mellonella . This research sheds light on the potential health risks of carbapenem- and polymyxin-resistant ECC strains displaying virulence in natural water bodies.
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DOI
高影响因子
Frontiers in Plant Science
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2020
·
IF 4.402
Ji Chao,Liu Zhaoyang,Hao Liping,Song Xin,Wang Changdong,Liu Yue,Li Huying,Li Chaohui,Gao Qixiong,Liu Xunli
The present study investigated the physiological and biochemical characteristics of Enterobacter cloacae HG-1 isolated from saline-alkali soil. We further studied the effect of this strain on the salt tolerance of wheat and on the community structure of nitrogen-fixing bacteria in rhizosphere soil. We determined that the investigated strain had high nitrogen fixation activity and produced iron carriers, 1-aminocyclopropane-1-carboxylic acid deaminase, and plant hormones. The metabolites of this strain contained 2,3-butanediol, [R-(R*, R*)], 2-heptanone, and other growth-promoting and antibacterial substances. The strain was also highly salt-tolerant (10% NaCl). After the inoculation of wheat with the HG-1 strain, we recorded increases in root length, plant height, fresh weight, and dry weight of 19.15%, 18.83%, 16.67%, and 17.96%, respectively, compared with uninoculated plants (P < 0.05). Compared with the leaves of uninoculated plants, the proline concentration in the leaves of inoculated plants increased by 12.43% (P < 0.05), the malondialdehyde level decreased by 27.26% (P < 0.05), K+ increased by 20.69%, Ca2+ increased by 57.53% and Na+ decreased by 31.43% (all P<0.05). Furthermore, we detected that inoculation with the HG-1 strain did not affect the species composition of nitrogen-fixing bacteria in wheat rhizosphere soil at the phylum level. However, the average relative abundance of Proteobacteria was significantly increased, whereas the abundance of Verrucomiorobia was significantly decreased compared with uninoculated plants. At the genus level, we detected 32 genera in control samples and 27 genera in inoculated samples, and the species diversity and relative abundance of samples inoculated with the HG-1 strain decreased compared with uninoculated plants. Inoculated samples had lower abundances of Azospirillum, Rhodomicrobium, and Anabaena. Our study demonstrated that the inoculation of wheat with E. cloacae HG-1 could promote the growth of wheat under salt stress and increase salt stress tolerance. The results of this study investigating the interaction among soil, plants, and microorganisms supplement agricultural microbial databases and could provide a reference for the development of microbial-based saline soil improvement programs.
研究领域:
微生物学
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农学
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土壤学
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植物生理学
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DOI
PubMed
高影响因子
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