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Guo L, Li Z, Xu J. Effects of Cadmium Stress on Bacterial and Fungal Communities in the Whitefly Bemisia tabaci. Int J Mol Sci 2023; 24:13588. [PMID: 37686394 PMCID: PMC10488276 DOI: 10.3390/ijms241713588] [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: 07/19/2023] [Revised: 08/23/2023] [Accepted: 08/31/2023] [Indexed: 09/10/2023] Open
Abstract
Heavy metal contamination is among the most prominent environmental problems in China, posing serious threats to both ecosystem and human health. Among the diverse heavy metal contaminants, cadmium is the most serious. The whitefly Bemisia tabaci is a cosmopolitan pest capable of causing severe damage to a broad range of agricultural crops, especially vegetables. At present, little is known about the effects of cadmium stress on B. tabaci, including on its bacterial and fungal communities. In the current study, we investigated the effects of cadmium on bacterial and fungal communities in whiteflies. Meta-barcode sequencing of the 16S rRNA gene revealed that the whitefly bacterial community contained 264 operational taxonomic units (OTUs) belonging to 201 known genera and 245 known species. The top five most frequent bacterial genera were Rickettsia, Rhodococcus, Candidatus Portiera, Candidatus Hamiltonella, and Achromobacter. Meta-barcode sequencing of the fungal ITS locus revealed that the whitefly fungal community contained 357 OTUs belonging to 187 known genera and 248 known species. The top five most frequent fungal genera were Wallemia, unclassified_f_Dipodascaceae, Apiotrichum, Penicillium, and unclassified_o_Saccharomycetales. Cadmium exposure reduced the fungal OTU richness but increased the bacterial Shannon and Simpson diversity indices in whiteflies. In addition, upon exposure to cadmium, the microbial community composition in whiteflies changed significantly, with increased prevalence of the bacterial genera Rhodococcus and Exiguobacterium and fungal genus Wallemia. Our results indicate that the whitefly microbiota likely contributed to their adaptation and resistance to cadmium and suggested that whiteflies may contain microbes that could help remediate cadmium contamination in natural environments and agricultural fields.
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Affiliation(s)
- Litao Guo
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, Changsha 410205, China; (L.G.); (Z.L.)
| | - Zhimin Li
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, Changsha 410205, China; (L.G.); (Z.L.)
| | - Jianping Xu
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
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Zhang Y, Shi K, Cui H, Han J, Wang H, Ma X, Li Z, Zhang L, Nie S, Ma C, Wang A, Liang B. Efficient biodegradation of acetoacetanilide in hypersaline wastewater with a synthetic halotolerant bacterial consortium. JOURNAL OF HAZARDOUS MATERIALS 2023; 441:129926. [PMID: 36099740 DOI: 10.1016/j.jhazmat.2022.129926] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 08/27/2022] [Accepted: 09/04/2022] [Indexed: 06/15/2023]
Abstract
The high concentrations of salt and refractory toxic organics in industrial wastewater seriously restrict biological treatment efficiency and functional stability. However, how to construct a salt-tolerant biocatalytic community and realize the decarbonization coupled with detoxification toward green bio-enhanced treatment, has yet to be well elucidated. Here, acetoacetanilide (AAA), an important intermediate for many dyes and medicine synthesis, was used as the model amide pollutant to elucidate the directional enrichment of halotolerant degradative communities and the corresponding bacterial interaction mechanism. Combining microbial community composition and molecular ecological network analyses as well as the biodegradation efficiencies of AAA and its hydrolysis product aniline (AN) of pure strains, the core degradative bacteria were identified during the hypersaline AAA degradation process. A synthetic bacterial consortium composed of Paenarthrobacter, Rhizobium, Rhodococcus, Delftia and Nitratireductor was constructed based on the top-down strategy to treat AAA wastewater with different water quality characteristics. The synthetic halotolerant consortium showed promising treatment ability toward the simulated AAA wastewater (AAA 100-500 mg/L, 1-5% salinity) and actual AAA mother liquor. Additionally, the comprehensive toxicity of AAA mother liquor significantly reduced after biological treatment. This study provides a green biological approach for the treatment of hypersaline and high concentration of organics wastewater.
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Affiliation(s)
- Yanqing Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Ke Shi
- Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil & Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China
| | - Hanlin Cui
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Jinglong Han
- Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil & Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China
| | - Hao Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Xiaodan Ma
- Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil & Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China
| | - Zhiling Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Ling Zhang
- School of Science, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China
| | - Shichen Nie
- Shandong Hynar Water Environmental Protection Co., Ltd., Caoxian, China
| | - Changshui Ma
- Tai'an Hospital of Chinese Medicine, Tai'an 271000, China
| | - Aijie Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China; Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil & Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China
| | - Bin Liang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China; Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil & Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China.
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Modification of nitrile hydratase from Rhodococcus erythropolis CCM2595 by semirational design to enhance its substrate affinity. Biointerphases 2022; 17:061007. [PMID: 36456206 DOI: 10.1116/6.0002061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Nitrile hydratase (NHase, EC 4.2.1.84) is an excellent biocatalyst that catalyzes the hydration of nitrile substances to their corresponding amides. Given its catalytic specificity and eco-friendliness, NHase has extensive applications in the chemical, pharmaceutical, and cosmetic industries. To improve the affinity between Rhodococcus erythropolis CCM2595-derived NHase (ReNHase) and adiponitrile, this study used a semirational design to improve the efficiency of ReNHase in catalyzing the generation of 5-cyanopentanamide from adiponitrile. Enzyme kinetics analysis showed that Km of the mutant ReNHaseB:G196Y was 3.265 mmol l-1, which was lower than that of the wild-type NHase. The affinity of the mutant ReNHaseB:G196Y to adiponitrile was increased by 36.35%, and the efficiency of the mutant ReNHaseB:G196Y in catalyzing adiponitrile to 5-cyanopentamide was increased by 10.11%. The analysis of the enzyme-substrate interaction showed that the hydrogen bond length of the mutant ReNHaseB:G196Y to adiponitrile was shortened by 0.59 Å, which enhanced the interaction between the mutant and adiponitrile and, thereby, increased the substrate affinity. Similarly, the structural analysis showed that the amino acid flexibility near the mutation site of ReNHaseB:G196Y was increased, which enhanced the binding force between the enzyme and adiponitrile. Our work may provide a new theoretical basis for the modification of substrate affinity of NHase and increase the possibility of industrial applications of the enzyme.
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"Toolbox" construction of an extremophilic nitrile hydratase from Streptomyces thermoautotrophicus for the promising industrial production of various amides. Int J Biol Macromol 2022; 221:1103-1111. [PMID: 36108746 DOI: 10.1016/j.ijbiomac.2022.09.071] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/23/2022] [Accepted: 09/08/2022] [Indexed: 11/23/2022]
Abstract
Nitrile hydratase (NHase; EC 4.2.1.84) is widely used to synthesize the corresponding amides from nitriles, which is the most successful green biocatalyst. However, the limited acceptability of substrates and instability under harsh reaction conditions have hindered its widespread industrial application. Here, a gene encoding an extremophilic NHase from Streptomyces thermoautotrophicus (S.t NHase) was successfully overexpressed in Escherichia coli. The enzyme exhibited excellent thermostability, retaining >50 % of residual activity after heat treatment at 65 °C for 252 min. To further improve the catalytic performance of S.t NHase, semi-rational engineering of its substrate access tunnel was performed. A mutant βL48D showed a specific activity of 566.18 ± 18.86 U/mg towards 3-cyanopyridine, which was 7.7 times higher than its parent enzyme (73.80 ± 5.76 U/mg). Molecular dynamics simulation showed that the introduction of aspartic acid into βLeu48 resulted in a larger and more frequent opening of the substrate access tunnel entrance. On this basis, a "toolbox" containing various mutants on the substrate access tunnel was further established, whose catalytic activity towards various nitrile substrates was extensively improved, showing great potential for efficient synthesis of multiple high-value amides.
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Vaishnav A, Kumar R, Singh HB, Sarma BK. Extending the benefits of PGPR to bioremediation of nitrile pollution in crop lands for enhancing crop productivity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 826:154170. [PMID: 35227717 DOI: 10.1016/j.scitotenv.2022.154170] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 02/06/2022] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
Incessant release of nitrile group of compounds such as cyanides into agricultural land through industrial effluents and excessive use of nitrile pesticides has resulted in increased nitrile pollution. Release of nitrile compounds (NCs) as plant root exudates is also contributing to the problem. The released NCs interact with soil elements and persists for a long time. Persistent higher concentration of NCs in soil cause toxicity to beneficial microflora and affect crop productivity. The NCs can cause more problems to human health if they reach groundwater and enter the food chain. Nitrile degradation by soil bacteria can be a solution to the problem if thoroughly exploited. However, the impact of such bacteria in plant and soil environments is still not properly explored. Plant growth-promoting rhizobacteria (PGPR) with nitrilase activity has recently gained attention as potential solution to address the problem. This paper reviews the core issue of nitrile pollution in soil and the prospects of application of nitrile degrading bacteria for soil remediation, soil health improvement and plant growth promotion in nitrile-polluted soils. The possible mechanisms of PGPR that can be exploited to degrade NCs, converting them into plant useful compounds and synthesis of the phytohormone IAA from degraded NCs are also discussed at length.
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Affiliation(s)
- Anukool Vaishnav
- Department of Biotechnology, GLA University, Mathura 281406, India; Agroecology and Environment, Agroscope (Reckenholz), Zürich 8046, Switzerland
| | - Roshan Kumar
- National Centre for Biological Sciences (TIFR-NCBS), Bengaluru 560065, India
| | | | - Birinchi Kumar Sarma
- Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221110, India.
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Ma S, Huang S, Tian Y, Lu X. Heterotrophic ammonium assimilation: An important driving force for aerobic denitrification of Rhodococcus erythropolis strain Y10. CHEMOSPHERE 2022; 291:132910. [PMID: 34793844 DOI: 10.1016/j.chemosphere.2021.132910] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
Studies on microbial ammonium removal have focused on the heterotrophic nitrification of microorganisms and have rarely studied the role of ammonium assimilation. In this study, Rhodococcus erythropolis strain Y10 with the capacity of aerobic denitrification was screened from the surface flow constructed wetlands that treat high-strength ammonium swine wastewater. Instead of through nitrification, this strain removed ammonium through heterotrophic ammonium assimilation, with the removal rate of 9.69 mg/L/h. The KEGG nitrogen metabolism pathway analysis combined with nitrogen balance calculation manifested that the removal of nitrate and nitrite by R. erythropolis Y10 was achieved through two pathways: 1) assimilation reduction to biomass nitrogen and 2) aerobic denitrification reduction to gaseous nitrogen. Ammonium addition improved the aerobic denitrification rate of nitrate and nitrite. The maximal reduction rates of nitrate and nitrite increased from 7.82 and 7.23 mg/L/h to 9.09 and 8.09 mg/L/h respectively, when 100 mg/L ammonium was separately added to 150 mg/L nitrate and nitrite. Furthermore, the removal efficiency of total nitrogen increased from 69.80% and 77.65% to 89.19% and 91.88%, respectively. Heterotrophic ammonium assimilation promoted the aerobic denitrification efficiency of Rhodococcus erythropolis strain Y10.
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Affiliation(s)
- Shu Ma
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
| | - Shiwei Huang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
| | - Yun Tian
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
| | - Xiangyang Lu
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China.
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Du W, Huang J, Cui B, Guo Y, Wang L, Liang C. Efficient biodegradation of nitriles by a novel nitrile hydratase derived from Rhodococcus erythropolis CCM2595. BIOTECHNOL BIOTEC EQ 2021. [DOI: 10.1080/13102818.2021.1941253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Affiliation(s)
- Wenjing Du
- Lab of Advanced Materials and Catalytic Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian, Liaoning, PR China
| | - Jiao Huang
- Lab of Biocalyalysis and Transformation, School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, Liaoning, PR China
| | - Baocheng Cui
- Lab of Biocalyalysis and Transformation, School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, Liaoning, PR China
| | - Yi Guo
- Lab of Biocalyalysis and Transformation, School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, Liaoning, PR China
| | - Li Wang
- Lab of Biocalyalysis and Transformation, School of Life and Pharmaceutical Sciences, Dalian University of Technology, Panjin, Liaoning, PR China
| | - Changhai Liang
- Lab of Advanced Materials and Catalytic Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian, Liaoning, PR China
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