Nai-Xian Feng

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Genome Mining-Guided Activation of Two Silenced Tandem Genes in Raoultella Ornithinolytica Xf201 for Complete Biodegradation of Phthalate Acid Esters

SSRN Electronic Journal (2022)

Nai-Xian Feng Fei Zhang Yunchang Xie Bin Hui Lei Xiang

Phthalates (PAEs) are ubiquitous in soils and food products and thus pose a high risk to human health. Herein, genome mining revealed a great diversity of bacteria with PAEs-degrading potential. Mining of the genome of Raoultella ornithinolytica XF201, a novel strain isolated from Dongxiang wild rice rhizosphere, revealed the presence of two silenced tandem genes pcdGH (encoding protocatechuate 3,4-dioxygenase, 3,4-PCD), key aromatic ring-cleaving genes in PAEs biodegradation. Ribosome engineering was successfully utilized to activate the expression of pcdGH genes to produce 3,4-PCD in the mutant XF201-G2U5. The mutant XF201-G2U5 showed high 3,4-PCD activity and could remove 94.5% of di-n butyl phthalate (DBP) in 72 hours. The degradation kinetics obeyed the first-order kinetic model. Strain XF201-G2U5 could also degrade the other PAEs and the main intermediate metabolites, ultimately leading to tricarboxylic acid cycle. Therefore, this strategy facilitates novel bacterial resources discovery for bioremediation of PAEs and other emerging contaminants.

10.2139/ssrn.4225401

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A Visual Leaf Zymography Technique for the In Situ Examination of Plant Enzyme Activity under the Stress of Environmental Pollution

Journal of Agricultural and Food Chemistry (2020)

Yuxi Feng Xin Chen Yan-Wen Li Hai-Ming Zhao Lei Xiang

This study established a high-efficiency fluorescence quenching approach for the in situ visualization and modeling of the spatial distribution of xylanase, β-glucosidase, and phosphatase activities in plant leaves under pollution stress (namely, the leaf zymography technique, LZT). In the LZT, a membrane saturated with an enzyme-specific fluorescent substrate on the leaf surface was incubated and the fluorescence image generated on the membrane under ultraviolet light was recorded. An image-based modeling method for restoring the morphological traits of the true image by reducing noise was developed to ensure the accurate estimation of enzyme activities. The LZT could simultaneously measure 48 samples within 2 h, with good reproducibility. The results obtained by the LZT were comparable to those obtained by a conventional biochemical analysis method and presented low-cost and convenient advantages. This paper explains the theoretical basis required to investigate the realistic application of the LZT for assessing ecotoxicity in large-scale monitoring.

Zymography

10.1021/acs.jafc.0c03815

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Citations (5)

Biodegradation of phthalate acid esters and whole-genome analysis of a novel Streptomyces sp. FZ201 isolated from natural habitats

Journal of Hazardous Materials (2024)

Nai-Xian Feng Dawei Li Fei Zhang Bin Hui Yi-Tong Huang

Phthalic acid

10.1016/j.jhazmat.2024.133972

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Citations (8)

Role and possible mechanisms of earthworm Eisenia fetida in the elimination of microcystin-LR in soil

Geoderma (2021)

Bailin Liu Yan-Wen Li Jingjie Guo Lei Xiang Hai-Ming Zhao

Eisenia fetida

10.1016/j.geoderma.2021.114980

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Citations (8)

Polyethylene and polypropylene microplastics reduce chemisorption of cadmium in paddy soil and increase its bioaccessibility and bioavailability

Journal of Hazardous Materials (2023)

Jingjie Guo LI Fen Haichuan Xiao Bailin Liu Lin-Nan Feng

10.1016/j.jhazmat.2023.130994

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Citations (25)

Effects of Arbuscular Mycorrhizal Fungi(AMF) on Growth and Cd accumulation of Upland Rice and Soil Enzyme Activities in Cadmium Contaminated Soil

Nongye huanjing kexue xuebao (2015)

Luo Fang-zhou Xiang Lei Hui Li Zhang Li-jun Nai-Xian Feng

Arbuscular mycorrhizal fungi(AMF)have showed to enhance plant resistance to environmental stresses. In this study, the effects of AMF(Glomus mosseae, GM)on growth and Cd accumulation and rhizospheric soil enzyme(urease and invertase)activities of upland rice were investigated under different Cd addition levels(0, 2, 10 mg·kg-1) in a pot trail. The colonization rates of upland rice roots by GM ranged from 37% to 72% and decreased with increasing soil Cd concentrations. The mycorrhizal colonization significantly enhanced soil en-zyme(urease and sucrase)activities(ranging from 9.6%~44.5%), promoted carbon and nitrogen metabolisms in the rhizosphere, and in-creased upland rice biomass(ranging from 10.4%~57.1%), as compared with the non-mycorrhizal upland rice. The uptake and transfer of Cd in upland rice and Cd concentrations in rice grains(ranging from 26.8%~57.1%)were significantly decreased by GM inoculation.

Upland rice

Glomus

Arbuscular mycorrhizal fungi

Sucrase

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Citations (4)

Bioaugmentation of two-stage aerobic sequencing batch reactor with mixed strains for high nitrate nitrogen wastewater treatment

Chinese Journal of Chemical Engineering (2020)

Mengmeng Wang Gang Cao Nai-Xian Feng Yongzhang Pan

Sequencing batch reactor

Bioaugmentation

Aerobic denitrification

10.1016/j.cjche.2020.08.014

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Citations (27)

Improved bio-electricity production in bio-electrochemical reactor for wastewater treatment using biomass carbon derived from sludge supported carbon felt anode

The Science of The Total Environment (2020)

Meng Li Yan-Wen Li Xiaolong Yu Jingjie Guo Lei Xiang

Carbon fibers

10.1016/j.scitotenv.2020.138573

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Citations (49)

Novel phosphate-solubilising bacteria isolated from sewage sludge and the mechanism of phosphate solubilisation

The Science of The Total Environment (2018)

Le-Yi Yu He-Biao Huang Xiaohong Wang Sha Li Nai-Xian Feng

Sewage sludge

Phosphate solubilizing bacteria

10.1016/j.scitotenv.2018.12.166

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Citations (45)

Highly Efficient and Simultaneous Analysis of Three Common Fluorotelomer Alcohols in Vegetables and Soils

Journal of Agricultural and Food Chemistry (2023)

Yu Zhang Si Wu Qian-Qi Chen Pengfei Yu Hai-Ming Zhao

Fluorotelomer alcohols (FTOHs), as precursors of perfluoroalkyl carboxylic acids, are difficult to analyze due to their high volatility and matrix interference. A method based on single-factor experiments and response surface methodology design was developed for simultaneous analysis of three common FTOHs in vegetables and soils, using single extraction, dispersive solid phase extraction cleanup, and gas chromatography-mass spectrometry in negative chemical ionization. The method improved the extraction efficiency up to ∼40 folds and showed a commendable linearity range (1-100 ng/mL, R2 > 0.991), low limit of detection (0.025-0.897 ng/g, dry weight (dw)), and high accuracy and precision (83 ± 7.2-117 ± 6.0% recoveries at 2-20 ng/g fortification levels). It was successfully applied to determine the FTOHs in real vegetables and soils, demonstrating its feasibility for routine analysis. Concentrations of the FTOHs ranged from 3.5 to 37.9 ng/g (dw) and from 6.5 to 141.0 ng/g (dw), respectively, in the vegetables and soils collected nearby fluorochemical factories, which warrants further investigations on FTOH pollution and food safety concerns for which the developed method will be useful.

10.1021/acs.jafc.3c01876

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Citations (3)