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Zhou J, Wang X, Sun Z, Gu C, Gao J. The mechanisms of ·OH formation in MnO 2 and oxalate system: Implication for ATZ removal. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134213. [PMID: 38613958 DOI: 10.1016/j.jhazmat.2024.134213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 03/20/2024] [Accepted: 04/02/2024] [Indexed: 04/15/2024]
Abstract
Manganese oxides (MnO2) are commonly prevalent in groundwater, sediment and soil. In this study, we found that oxalate (H2C2O4) dissolved MnO2, leading to the formation of Mn(II)/(III), CO2(aq) and reactive oxygen species (·CO2-/O2·-/H2O2/·OH). Notably, CO2(aq) played a crucial role in ·OH formation, contributing to the degradation of atrazine (ATZ). To elucidate underneath mechanisms, a series of reactions with different gas-liquid ratios (GLR) were conducted. At the GLR of 0.3, 3.76, and + ∞ 79.4 %, 5.32 %, and 5.28 % of ATZ were eliminated, in which the cumulative ·OH concentration was 39.6 μM, 8.11 μM, and 7.39 μM and the cumulative CO2(aq) concentration was 11.2 mM, 4.7 mM, and 2.8 mM, respectively. The proposed reaction pathway was that CO2(aq) participated in the formation of a ternary complex [C2O4-Mn(II)-HCO4·3 H2O]-, which converted to a transition state (TS) as [C2O4-Mn(II)-CO3-OH·3 H2O]-, then decomposed to a complex radical [C2O4-Mn(II)-CO3·3 H2O]·- and ·OH after electron transfer within TS. It was novel to discover the role of CO2(aq) for ·OH yielding during MnO2 dissolution by H2C2O4. This finding helps revealing the overlooked processes that CO2(aq) influenced the fate of ATZ or other organic compounds in environment and providing us ideas for new technique development in contaminant remediation. ENVIRONMENTAL IMPLICATION: Manganese oxides and oxalate are common in soil, sediment and water. Their interactions could induce the formation of Mn(II)/(III), CO2(aq) and ·CO2-/O2·-/H2O2. This study found that atrazine could be effectively removed due to ·OH radicals under condition of high CO2(aq) concentration. The concentrations of Mn (0.0002-8.34 mg·L-1) and CO2(aq) (15-40 mg·L-1) were high in groundwater, and the surface water or rainfall seeps into groundwater and bring organic acids, which might promote the ·OH formation. The results might explain the missing steps of herbicides transformation in these environments and be helpful in developing new techniques in remediation in future.
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Affiliation(s)
- Jinjin Zhou
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Nanjing, No.188, Tianquan Road, Nanjing, Jiangsu Province 211135, China
| | - Xinghao Wang
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Zhaoyue Sun
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Cheng Gu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Juan Gao
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Nanjing, No.188, Tianquan Road, Nanjing, Jiangsu Province 211135, China.
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Qi Y, Qin Q, Liao G, Tong L, Jin C, Wang B, Fang W. Unveiling the super tolerance of Candida nivariensis to oxidative stress: insights into the involvement of a catalase. Microbiol Spectr 2024; 12:e0316923. [PMID: 38206032 PMCID: PMC10846165 DOI: 10.1128/spectrum.03169-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/30/2023] [Indexed: 01/12/2024] Open
Abstract
Yeast cells involved in fermentation processes face various stressors that disrupt redox homeostasis and cause cellular damage, making the study of oxidative stress mechanisms crucial. In this investigation, we isolated a resilient yeast strain, Candida nivariensis GXAS-CN, capable of thriving in the presence of high concentrations of H2O2. Transcriptomic analysis revealed the up-regulation of multiple antioxidant genes in response to oxidative stress. Deletion of the catalase gene Cncat significantly impacted H2O2-induced oxidative stress. Enzymatic analysis of recombinant CnCat highlighted its highly efficient catalase activity and its essential role in mitigating H2O2. Furthermore, over-expression of CnCat in Saccharomyces cerevisiae improved oxidative resistance by reducing intracellular ROS accumulation. The presence of multiple stress-responsive transcription factor binding sites at the promoters of antioxidative genes indicates their regulation by different transcription factors. These findings demonstrate the potential of utilizing the remarkably tolerant C. nivariensis GXAS-CN or enhancing the resistance of S. cerevisiae to improve the efficiency and cost-effectiveness of industrial fermentation processes.IMPORTANCEEnduring oxidative stress is a crucial trait for fermentation strains. The importance of this research is its capacity to advance industrial fermentation processes. Through an in-depth examination of the mechanisms behind the remarkable H2O2 resistance in Candida nivariensis GXAS-CN and the successful genetic manipulation of this strain, we open the door to harnessing the potential of the catalase CnCat for enhancing the oxidative stress resistance and performance of yeast strains. This pioneering achievement creates avenues for fine-tuning yeast strains for precise industrial applications, ultimately leading to more efficient and cost-effective biotechnological processes.
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Affiliation(s)
- Yanhua Qi
- Institute of Biological Science and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Qijian Qin
- Institute of Biological Science and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Guiyan Liao
- Institute of Biological Science and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Lige Tong
- Institute of Biological Science and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Cheng Jin
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Bin Wang
- Institute of Biological Science and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Wenxia Fang
- Institute of Biological Science and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
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Sun J, Wang Y, Zheng Y, Yuan M, Zhang H, Huo G, Weng M, Jiang R, Zhang Y, Wang Y. Improved titer and stability of selenium nanoparticles produced by engineered Saccharomyces cerevisiae. Enzyme Microb Technol 2024; 173:110367. [PMID: 38070448 DOI: 10.1016/j.enzmictec.2023.110367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 12/23/2023]
Abstract
Selenium nanoparticles (SeNPs) have gained significant attention in the fields of medicine and healthcare products due to their various biological activities and low toxicity. In this study, we focused on genetically modifying the Saccharomyces cerevisiae strain YW16 (CICC 1406), which has the ability to efficiently reduce sodium selenite and produce red SeNPs. By overexpressing genes involved in glutathione production, we successfully increased the glutathione titer of the modified strain YJ003 from 41.0 mg/L to 212.0 mg/L. Moreover, we improved the conversion rate of 2.0 g/L sodium selenite from 49.3% to 59.6%. Furthermore, we identified three surface proteins of SeNPs, and found that overexpression of Act1, one of the identified proteins, led to increased stability of SeNPs across different acid-base and temperature conditions. Through a 135-h feed fermentation process using 5.0 g/L sodium selenite, we achieved an impressive conversion rate of 88.7% for sodium selenite, and each gram of SeNPs contained 195.7 mg of selenium. Overall, our findings present an efficient method for yeast to synthesize SeNPs with high stability. These SeNPs hold great potential for applications in nanomedicine or as nutritional supplements to address selenium deficiency.
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Affiliation(s)
- Jie Sun
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Yi Wang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Yixuan Zheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Mengjie Yuan
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Hangjun Zhang
- Hangzhou Seasy Biotechnology Co., Ltd., Hangzhou 311100, China
| | - Guangliang Huo
- Hangzhou Seasy Biotechnology Co., Ltd., Hangzhou 311100, China
| | - Ming Weng
- Hangzhou Seasy Biotechnology Co., Ltd., Hangzhou 311100, China
| | - Ruicheng Jiang
- International Division, The Affiliated High School to Hangzhou Normal University, Hangzhou 310000, China
| | - Yinjun Zhang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Yuguang Wang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
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Xie M, Gao X, Zhang S, Fu X, Le Y, Wang L. Cadmium stimulated cooperation between bacterial endophytes and plant intrinsic detoxification mechanism in Lonicera japonica thunb. CHEMOSPHERE 2023; 325:138411. [PMID: 36931404 DOI: 10.1016/j.chemosphere.2023.138411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 01/16/2023] [Accepted: 03/13/2023] [Indexed: 06/18/2023]
Abstract
Due to the intimate association between plant physiology and metabolism, the internal colonizing microbe (endophytes) community must be adjusted to support plant productivity in response to cell damage in plants under stress. However, how endophytes coordinate their activities with plant intrinsic mechanisms such as antioxidative systems and detoxification pathways during Cd accumulation remains unknown. In this hydroponic pot study, we investigated how exposure of Lonicera japonica. thunb. to different levels of Cd (0.5, 2.5, 5, 10, and 20 mg kg-1) affected plant growth, metabolic pathways, and endophyte community structure and function. Although Cd accumulation increased at 5 mg kg-1 Cd, the biomass and height of L. japonica increased in association with elevated endophyte-involved plant detoxification activities. Endophytes, such as Sphingomonas, Klenkia, and Modestobacter, expressed major antioxidative regulators (superoxide dismutase and ascorbate acid) to detoxify Cd in L. japonica. Furthermore, L. japonica and its endophytes synergistically regulated the toxic effects of Cd accumulation via multiple plant metabolic defensive pathways to increase resistance to metal-induced stress.
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Affiliation(s)
- Mengdi Xie
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Xiaoyu Gao
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Saiwei Zhang
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Xiaohua Fu
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Yiquan Le
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Lei Wang
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
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