JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2024
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IF 5.7
Qi Han,Youwen Xing,Lulu Yan,Lulu Cao,Zehao Li,Jiandong Jiang,Xihui Xu,Chen Chen
Cyromazine, a triazine insecticide, raises food safety concerns due to residues in vegetables like cowpeas. Microbial metabolism is key for pesticide elimination, but bacteria efficient in cyromazine degradation are limited, with uncharacterized enzymes. This study isolated a highly efficient cyromazine-degrading bacterium, Mycobacterium sp. M15, from a cowpea field. M15 utilized cyromazine as the sole carbon source for its growth and completely degraded 0.5 mM cyromazine within 24 h. The degradation pathway involved hydrolyzing cyromazine to N-cyclopropylammeline and further to N-cyclopropylammelide, with amino groups removed sequentially. The cyclopropylamine group in N-cyclopropionamide continued to hydrolyze to cyanuric acid. A protein, CriA, identified as an aminohydrolase in M15, degraded cyromazine to N-cyclopropylammeline. Using CriA reduced cyromazine residues on cowpea surfaces and completely degraded them in immersion solutions. These findings offer insights into cyromazine’s microbial degradation mechanism and highlight the potential of cyromazine-degrading enzymes in enhancing food safety.
研究领域:
环境科学
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微生物学
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生物技术
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农药化学
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DOI
PubMed
高影响因子
RSC Advances
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2016
·Vol. 6
·期 18
·14993-15001
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IF 3.289
Mu Li,Yinguang Chen,Yinglong Su,Rui Wan,Xiong Zheng
The influences of three fulvic acids, referred to as SAFA (purchased from Shanghai Aladdin Reagent Company), SRFA (Suwannee River Fulvic Acid from International Humic Substances Society (IHSS)) and PPFA (Pahokee Peat Fulvic Acid from IHSS), with different chemical composition, structure, hydrophobicity and aromaticity degree on biological wastewater denitrification were investigated. It was found that SAFA remarkably enhanced the denitrification performance, while SRFA and PPFA had no obvious effect. Mechanistic study revealed that SAFA remarkably improved the metabolism of a carbon source (glucose) by stimulating the activities of key enzymes (hexokinase, 6-phosphofructose kinase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and pyruvate kinase) involved in glycolysis. The increase of glucose utilization resulted in the increase of intracellular NADH/NAD+ ratio that favored microbial denitrification. Meanwhile the bacterial growth was significantly improved in the presence of SAFA. Further studies revealed that SAFA also increased the activities of key denitrifying enzymes, including nitrate reductase (NAR), nitrite reductase (NIR), nitric oxide reductase (NOR), and nitrous oxide reductase (N2OR), thus enhancing the reduction of nitrate and transformation of its intermediates, especially nitrite and nitrous oxide. All the above positive effects posed by SAFA might be attributed to its lower molecular weight, less complex aromatic structures with predominantly aliphatic carbons and higher hydrophilicity than SRFA and PPFA, which lead to a more active interaction with denitrifying microorganisms via metabolism process regulation. A better knowledge of the relationship between molecular structure of fulvic acids and microbial denitrification activity may be of practical interest in the nitrogen cycle in nature's niches.
研究领域:
环境科学
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微生物学
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DOI
高影响因子
FOOD CHEMISTRY
·
2025
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IF 9.8
Xin Yang,Yichun Sun,Xuanchen Li,Nana Zhang,Zhengfang Qi,Anyan Wen,Likang Qin,Haiying Zeng
Monascus -fermented coix seed exhibits enhanced tocopherol accumulation compared to other strains, yet mechanisms remain unclear. Whether Monascus metabolites/enzymes drive this enrichment is worth exploring. Comparative genomics and transcriptomics were employed to analyze secondary metabolite profiles and tocopherol enrichment capabilities across Monascus strains. The results revealed that γ-aminobutyric acid (GABA) derived from amino acid metabolism is channeled into both the Shikimate pathway to generate homogentisic acid (a tocopherol precursor) and the Mevalonate pathway to produce ergosterol and geranylgeranyl diphosphate (another precursor). Furthermore, the total tocopherol content of M1 and M1 + 3 reached 168 and 148 μg/g DW, positively correlating with ergosterol content ( p < 0.05). Transcriptomic data further demonstrated strain-specific differences in tocopherol enrichment, linked to upregulated expression of key genes ( HPPD , ERG4 , MVD , FDPS , GGPS1 ) governing precursor biosynthesis. Crucially, we validated that ergosterol acts as a stimulator of tocopherol synthesis, directly supporting our hypothesis on pathway crosstalk. This study elucidates microbial-driven tocopherol enrichment mechanisms via precursor allocation and transcriptional regulation, providing insights into bioactive compound synthesis in complex metabolic networks.
研究领域:
微生物学
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生物化学
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功能食品科学
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DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2018
·Vol. 25
·期 27
·27274-27282
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IF 2.8
Luo Jingyang,Zhang Qin,Wu Lijuan,Cao Jiashun,Feng Qian,Fang Fang,Chen Yinguang
1,4-Dioxane is an emerging pollutant, which widely exists in natural environments and poses potential risks to the living organisms. However, its effect on the denitrification process is still unknown. In this study, the effects of 1,4-dioxane on the denitrification process were therefore investigated by using Paracoccus denitrificans as the model denitrifier. The obtained results showed that the exposure of 1,4-dioxane exhibited remarkable lag or inhibition on the denitrification process, especially with high dose. In the control without 1,4-dioxane exposure, Paracoccus denitrificans showed high denitrification efficiency (98.5%). However, the efficiency decreased to 78.5, 63.9, and 9.3% with 0.50, 0.75, and 1.0% ( v / v ) 1,4-dioxane dose, respectively. The dose-induced inhibition of denitrification by 1,4-dioxane could be partially attributed to the negative effects on proliferation and viability of functional microorganisms by conjugating and disrupting the cell membranes. Furthermore, 1,4-dioxane caused biotoxicity to the intracellular activities of denitrifiers via disturbing carbon source utilization and interfering the key enzymes responsible for glycolysis. The decrease of microbial viability and activity inevitably resulted in the decline of key enzymes (NAR, NIR, NOR, and N 2 OR) closely related with denitrification process, which could be the direct reason for the decrease of denitrification performance.
研究领域:
环境生物学
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微生物学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2019
·Vol. 94
·期 10
·3201-3207
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IF 2.659
Yong Jin,Ming Gao,Hongai Li,Yujia Lin,Qunhui Wang,Maobing Tu,Hongzhi Ma
BACKGROUND The proper dosage of nanoscale zerovalent iron (NZVI) for volatile fatty acid (VFA) production was optimized and different kinds of organic acids and key enzymes during the process were analyzed to test the effect of NZVI on VFA fermentation from food waste. RESULTS Batch assays showed that proper NZVI dosage can promote VFA production, reaching the maximum accumulation of 22 250 mg COD L −1 at 10 g L −1 dosage, which is 1.92 times higher than that of the control group. Acetic acid accounted for the highest proportion (72%) of VFAs, and lactic acid was the main by-product of organic acids. The addition of NZVI provided a reducing power for the lactic acid fermentation in the system, which promoted the conversion of pyruvic acid to lactic acid. Moreover, the addition of NZVI not only greatly promoted the activity of ferredoxin oxidoreductase (0.35 IU g −1 ) and acetyl-CoA (1.47 IU g −1 ) but also caused changes in the microbial community structure in the fermentation system. After adding NZVI, besides Lactobacillus , Olsenella (12.69%) was another dominant bacterium which can rapidly convert the produced lactic acid into short-chain fatty acids (SCFAs), thereby affecting acid production. CONCLUSION These key enzymes resulted in the accumulation of VFAs. The fermentative bacteria responsible for SCFA production were also highly enriched in fermentation reactors with NZVI, which was in accordance with the accumulation of SCFAs. © 2019 Society of Chemical Industry
研究领域:
环境科学
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微生物学
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生物技术
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DOI
高影响因子
WATER RESEARCH
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2015
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IF 5.528
Xiaomeng Han,Zhiwei Wang,Xueye Wang,Xiang Zheng,Jinxing Ma,Zhichao Wu
Sodium hypochlorite (NaClO) is a commonly used reagent for membrane cleaning in membrane bioreactors (MBRs), while it, being a kind of disinfectant (oxidant), may impair viability of microbes or even totally inactivate them upon its diffusion into mixed liquor during membrane cleaning. In this study, we systematically examine the effects of NaClO on microorganisms in terms of microbial cell integrity, metabolism behaviours (key enzymes), and intracellular reactive oxygen species (ROS) under various NaClO concentrations. Different proportions of microbial cells in activated sludge were damaged within several minutes dependent on NaClO dosages (5–50 mg/g-SS), and correspondingly organic matters were released to bulk solution. Inhibition of key enzymes involved in organic matter biodegradation, nitrification and denitrification was observed in the presence of NaClO above 1 mg/g-SS, and thus organic matter and nitrogen removal efficiencies were decreased. It was also demonstrated that intracellular ROS production was increased with the NaClO dosage higher than 1 mg/g-SS, which likely induced further damage to microbial cells.
研究领域:
环境工程
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微生物学
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产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
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2022
·
IF 8.943
Xiaoying Zheng,Huijie Zhang,Zhi Xu,Tao Lin,Shanshan Yang,Zhilin Zhao,Zongshuo Han,Chao Zhou
The widespread use of perfluorooctanoic acid (PFOA) has rendered its frequent detection in wastewater. The tolerance and recovery of aerobic granular sludge (AGS) to PFOA were investigated in short-term (Phase Ⅰ) and long-term (Phase Ⅱ, operation strategy adjustment: shortening aeration time and prolonging anaerobic and anoxic time). Results showed that in Phase Ⅰ, the performance of R2 reactor (0.05 mg/L PFOA) was slightly negatively affected, while 0.5 and 2.0 mg/L PFOA in R3 and R4 reactors significantly damaged the key enzyme activities of AGS, leading to deterioration of nutrients removal. TN and TP removal efficiencies decreased correspondingly from 79.32% to 78.41% on day 0 to 74.66% and 74.14% in R2 and 68.57% and 67.80% in R3 and 56.94% and 57.47% in R4 on day 7, respectively. In Phase Ⅱ, the key enzyme activities of AGS were obviously renewed dependent on operation strategy adjustment and AGS self-regulation. The performance of AGS in R2 (continuously dosing 0.05 mg/L PFOA) and R4 (stopping dosing PFOA) recovered quite good, while the long-term adverse effects of 0.5 mg/L PFOA on AGS in R3 were still more difficult to be alleviated. In end of Phase Ⅱ (69–97days), the average TN and TP removal efficiencies correspondingly reached 83.31% and 82.09% in R1 (control), 80.67% and 79.62% in R2, 76.38% and 74.27% in R3, and 79.01% and 78.25% in R4, respectively. Further analysis revealed that the effect of PFOA on proteins in extracellular polymeric substances (EPS) was greater than that on polysaccharides . Specifically, short-term dosage of PFOA mainly affected loosely bound EPS, while long-term dosage of PFOA affected tightly bound EPS. Although AGS is severely inhibited by short exposure to 2.0 mg/L PFOA (in R4), after the operation strategy adjustment, EPS content decreased, nutrient and oxygen transport channels of AGS were re-established, which contributed to the recovery of AGS.
研究领域:
环境工程
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污水处理
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微生物学
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jin Xu,Xiuhong Liu,Yimai Zhou,Shiyong Zhang,Jiaxin Li,Qing Yang
NaClO, as a common membrane cleaning agent were introduced from the permeate side across membrane, which could diffuse into MBR membrane pool. Microplastics would also accumulate in MBR membrane pool during wastewater treatment, thus, NaClO and MPs are co-exposed to activated sludge. This study investigated the effects of PET-MPs (0, 50, 100 and 300 μg/g-ss) on activated sludge with or without NaClO stress. The presence of PET-MPs had no significant impact on nitrification and denitrification rates, but when exposed to NaClO, the increasing level of PET-MPs (i.e., from 0 to 300 μg/g-ss) inhibited the nitrification (94.85 % to 65.90 %) and denitrification (88.68 % to 60.09 %) rates. For microbial metabolism (key enzymes) evaluated, the key enzymes related to organic matter biodegradation, nitrification as well as denitrification were both inhibited with PET-MPs level rise under NaClO stress. The generation of reactive oxygen species (ROS) and the release of lactate dehydrogenase (LDH) increased significantly indicating NaClO caused the toxicity of MPs to activated sludge by enhancing the oxidative stress level. Correspondingly, a variation in abundance related to membrane pollution, nitrification, and denitrification after exposure to PET-MPs with NaClO stress accompanied these adverse effects.
研究领域:
环境工程
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废水处理
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微生物学
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毒理学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
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IF 13.3
Dan Li,Weixin Zhao,Shuocheng Shao,Zixuan Zhao,Jianju Li,Likui Feng,Shijie You,Chuandong Wu,Liangliang Wei
Peroxydisulfate (PDS) additive has been proven as an effective strategy to enhance short-chain fatty acids (SCFAs) production from waste activated sludge (WAS), which can achieve dual objectives of waste disposal and resource recovery. However, the high cost of PDS limits its large-scale application in sludge treatment. This study explored the feasibility of using natural pyrite (FeS 2 ) as an activator for PDS to enhance its capacity for promoting SCFAs production while reducing the required dosage. Compared to sole PDS (1 mM/g volatile suspended solids (VSS)), FeS 2 /PDS co-treatment (0.5 mM/g VSS PDS + 0.6 mM/g VSS FeS 2 ) obviously increased the maximum SCFAs production from 4589.5 mg COD/L to 5951.3 mg COD/L, accompanied with an enhanced proportion of acetate from 62.0 % to 75.2 %. Mechanism exploration revealed that FeS 2 /PDS enhanced the generation of hydroxyl radicals (•OH) and sulfate radicals (SO 4 •− ), thereby promoting WAS solubilization and hydrolysis. The detectable soluble chemical oxygen demand within the supernatant after 4 days of co-treatment fermentation was 5.3-fold higher than that in the single FeS 2 test and 2.0-fold higher than that in the single PDS test. Meanwhile, the activities of key enzymes, including protease, α-glucosidase, acetate kinase, and butyrate kinase, were also significantly enhanced after the FeS 2 /PDS treatment, accompanied with an increase in the abundance of hydrolytic and acidogenic microorganisms such as Acinetobacter , Clostridium_sensu_stricto , and Fonticella . Besides, FeS 2 /PDS co-treatment improved the dewaterability (42.7 % reduction in capillary suction time) and reduced operation cost (37.9 % decrease), as compared to the sole PDS (1 mM/g VSS) treatment. These findings suggest that FeS 2 /PDS co-treatment is a promising and cost-effective technique to enhance WAS anaerobic fermentation.
研究领域:
环境工程
·
废物管理
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生物技术
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生化工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）