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Zhao ZQ, Wei XM, Shen XL, Abbas G, Fan R, Jin Y. Aerobic degradation of 4-fluoroaniline and 2,4-difluoroaniline: performance and microbial community in response to the inocula. Biodegradation 2021; 32:53-71. [PMID: 33428058 DOI: 10.1007/s10532-021-09925-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 01/02/2021] [Indexed: 11/27/2022]
Abstract
In this study, a distinct inoculum was investigated as an isolated variable within sequencing batch reactors via a comparison of the 4-fluoroaniline (4-FA) or 2,4-difluoroaniline (2,4-DFA) removal amounts. The inocula were derived from a treatment plant for treating pharmaceutical wastewater plus a small amount of municipal sewage (PMS), a treatment plant for treating fluoridated hydrocarbon wastewater (FHS), and a treatment plant for treating the comprehensive wastewater in an industrial park (CIS). There were slight differences among the degradation patterns of the 4-FA for the three inocula, whether during the enrichment period or the high concentration shock period. In contrast, it was observed that the degradation efficiency of 2,4-DFA initially varied with the inocula. The FHS-derived inoculum was determined to be optimal, exhibiting the earliest degradation reaction only after an acclimation of 7 days had the highest degradation rate constant of 0.519 h-1, and had the fastest recovery time of three weeks after high concentration shock. Additionally, compared with the PMS-derived inoculum, the CIS-derived inoculum exhibited an earlier degradation reaction within three weeks, and a higher microbial diversity, but a lower shock resistance and degradation rate constant of 0.257 h-1. High-throughput sequencing demonstrated that each final consortium was different in composition, and the microbial consortia developed well on the inoculum and substrate. In comparison of the similarity among the three 2,4-DFA enrichment cultures, the higher similarity (63.9-70.0%) among three final consortia enriching with 4-FA was observed. The results indicated that the inoculum played an important role in the degradation of FAs and the microbial bacterial communities of final consortia, and the effect extent might well depend on the fluorinated level of FAs.
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Affiliation(s)
- Zhi-Qing Zhao
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China. .,College of Environment & Resource Sciences, Zhejiang University, Hangzhou, People's Republic of China.
| | - Xiao-Meng Wei
- Key Laboratory of Agro-Ecological Processes in Subtropical Region & Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, China
| | - Xiao-Li Shen
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China
| | - Ghulam Abbas
- Department of Chemical Engineering, University of Gujrat, Gujrat, 50700, Pakistan
| | - Rui Fan
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China
| | - Yi Jin
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China
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Zhao ZQ, Shen XL, Zheng TC, Lv L, Su Y, Ghulam A. Aerobic degradation of 2- and 3-fluoroaniline in mixed culture systems and microbial community analysis. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2019; 55:305-317. [PMID: 31707907 DOI: 10.1080/10934529.2019.1688044] [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: 06/24/2019] [Revised: 10/24/2019] [Accepted: 10/25/2019] [Indexed: 06/10/2023]
Abstract
Among three monofluoroanilines, 2-fluoroaniline (2-FA) and 3-fluoroaniline (3-FA) exhibit relatively poor biodegradability. This work examined their degradation characteristics in a mixed culture system and also analyzed the microorganism community. After acclimation for 58 d and 43 d, the high removal efficiency of 100% of 2-FA and 95.3% of 3-FA was obtained by adding 25 mg L-1 of 2-FA or 3-FA to the two reactors, respectively. In addition, the high defluorination rates of 2-FA and 3-FA were observed to be 87.0% and 89.3%, respectively. The degradation kinetics showed that the maximum specific degradation rates of 2-FA and 3-FA were (21.23 ± 0.91) mg FA (g•VSS·h)-1, and (11.75 ± 0.99) mg FA (g•VSS·h)-1, respectively. PCR-DGGE analysis revealed that the unique bacteria degrading 2-FA were mainly composed of six genera (Novosphingobium, Bradyrhizobium, Aquaspirillum, Aminobacter, Ochrobactrum, and Labrys), and five genera that degraded 3-FA (Ochrobactrum, Aquaspirillum, Lachnobacterium, Bradyrhizobium, and Variovorax). Analysis of the key catabolic enzyme activities indicated that the simultaneous hydroxylation and dehalogenation were involved in monooxygenase elimination of 2-FA and conversion of 3-FA to 4-fluorocatechol by dioxygenase, indicating that enriched mixed cultures were effective to metabolize 2-FA or 3-FA by unconventional pathways to prevent the accumulation of toxic metabolites.
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Affiliation(s)
- Zhi-Qing Zhao
- College of Chemical & Material Engineering, Quzhou University, Quzhou, P.R. China
- College of Environment & Resource Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Xiao-Li Shen
- College of Chemical & Material Engineering, Quzhou University, Quzhou, P.R. China
| | - Tu-Cai Zheng
- College of Chemical & Material Engineering, Quzhou University, Quzhou, P.R. China
| | - Liang Lv
- College of Chemical & Material Engineering, Quzhou University, Quzhou, P.R. China
| | - Yao Su
- Department of Agroenvironmental Engineering, Environmental Resources and Soil Fertilizer Research Institute, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Abbas Ghulam
- Department of Chemical Engineering, University of Gujrat, Gujrat, Pakistan
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Zhao ZQ, Zheng TC, Zhang WJ, Shen XL, Lv L, Li YM. Degradation of 3-fluoroanilne by Rhizobium sp. JF-3. Biodegradation 2019; 30:433-445. [PMID: 31240422 DOI: 10.1007/s10532-019-09885-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 06/19/2019] [Indexed: 01/07/2023]
Abstract
The interest of fluoroanilines in the environment is due to their extensive applications in industry and their low natural biodegradability. A pure bacterial strain capable of degrading 3-fluoroaniline (3-FA) as the sole source of carbon and energy was isolated from a sequencing batch reactor operating for the treatment of 3-FA. The strain (designated as JF-3) was identified by 16S rRNA gene analysis as a member of the genus Rhizobium. When grown in 3-FA medium at concentrations of 100-700 mg/L, strain JF-3 almost completely removed 3-FA within 72 h. However, the obvious cell growth inhibition was observed in cultures treated with 3-FA concentrations greater than 500 mg/L. The degradation kinetics of 3-FA were consistent with Haldane's model with the maximum degradation rate as 67.66 mg/(g dry cell h). The growth kinetics of strain JF-3 followed Andrew's model with the maximum growth rate as 30.87 h-1. Also, strain JF-3 was able to degrade 4-fluoroaniline, aniline, and catechol, but hardly grew on 2-fluoroaniline, 2,4-dfluoroaniline, 2,3,4-trifluoroaniline, 3-fluorocatechol, and 4-fluorocatechol. Additionally, it was able to grow over a wide pH range (pH 6-10), and also showed tolerance to salinity with lower than 1.0%. This result, in combination with the enzyme assays and analysis of metabolite intermediates, indicated an unconventional pathway for 3-fluoroaniline metabolism that involved conversion to 3-aminophenol and resorcinol by monooxygenase, and which was subsequently metabolized via the ortho-cleavage pathway. To our knowledge, this is the first report on the utilization of 3-FA as a growth substrate by Rhizobium sp.
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Affiliation(s)
- Zhi-Qing Zhao
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China. .,College of Environment & Resource Sciences, Zhejiang University, Hangzhou, People's Republic of China.
| | - Tu-Cai Zheng
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China
| | - Wen-Jing Zhang
- Institute of Environmental Planning, Ministry of Environmental Protection, Beijing, 100012, People's Republic of China
| | - Xiao-Li Shen
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China
| | - Liang Lv
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China
| | - Yan-Mei Li
- Engineering Division, Department of Mine, Metallurgy and Geology Engineering, University of Guanajuato, Guanajuato, Gto, 36000, Mexico
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Dithugoe CD, van Marwijk J, Smit MS, Opperman DJ. An Alcohol Dehydrogenase from the Short-Chain Dehydrogenase/Reductase Family of Enzymes for the Lactonization of Hexane-1,6-diol. Chembiochem 2018; 20:96-102. [PMID: 30252998 DOI: 10.1002/cbic.201800533] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Indexed: 01/20/2023]
Abstract
Biocatalytic production of lactones, and in particular ϵ-caprolactone (CL), have gained increasing interest as a greener route to polymer building blocks, especially through the use of Baeyer-Villiger monooxygenases (BVMOs). Despite several advances in the field, BVMOs, however, still suffer several practical limitations. Alcohol dehydrogenase (ADH)-mediated lactonization of diols in turn has received far less attention and very few enzymes have been identified for the conversion of diols to lactones, with horse-liver ADH (HLADH) remaining the catalyst of choice. Screening of a diverse panel of ADHs, AaSDR-1, a member of the short-chain dehydrogenase/reductase family, was found to produce ϵ-caprolactone from hexane-1,6-diol. Moreover, cofactor regeneration by an NADH oxidase eliminated the requirement of co-substrates, yielding water as the sole by-product. Despite lower turnover frequencies as compared to HLADH, higher selectivity was found for the production of CL, with HLADH forming significant amounts of 6-hydroxyhexanoic acid and adipic acid through aldehyde dehydrogenation/oxidation of the gem-diol intermediates. Also, CL yield were shown to be dependent on buffer choice, as structural elucidation of a Tris adduct confirmed the buffer amine to react with aliphatic aldehydes forming a Schiff-base intermediate which through further ADH oxidation, forms a tricyclic acetal product.
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Affiliation(s)
- Choaro D Dithugoe
- Department of Biotechnology, University of the Free State, 205 Nelson Mandela Drive, Bloemfontein, 9300, South Africa
| | - Jacqueline van Marwijk
- Department of Biotechnology, University of the Free State, 205 Nelson Mandela Drive, Bloemfontein, 9300, South Africa
| | - Martha S Smit
- Department of Biotechnology, University of the Free State, 205 Nelson Mandela Drive, Bloemfontein, 9300, South Africa
| | - Diederik J Opperman
- Department of Biotechnology, University of the Free State, 205 Nelson Mandela Drive, Bloemfontein, 9300, South Africa
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