Evaluation of Beta-Cyfluthrin Biodegradation by a Novel Bacterial Consortium: Microbial Succession, Degradation Pathway and Toxicity Assessment

The application of microorganisms in azo dye remediation has gained significant attention, leading to various published studies reporting different methods for obtaining the best dye decolouriser. This paper investigates and compares the role of methods and media used in obtaining a bacterial consortium capable of decolourising azo dye as the sole carbon source, which is extremely rare to find. It was demonstrated that a prolonged acclimation under low substrate availability successfully isolated a novel consortium capable of utilising Reactive Red 120 dye as a sole carbon source in aerobic conditions. This consortium, known as JR3, consists of Pseudomonas aeruginosa strain MM01, Enterobacter sp. strain MM05 and Serratia marcescens strain MM06. Decolourised metabolites of consortium JR3 showed an improvement in mung bean’s seed germination and shoot and root length. One-factor-at-time optimisation characterisation showed maximal of 82.9% decolourisation at 0.7 g/L ammonium sulphate, pH 8, 35 °C, and RR120 concentrations of 200 ppm. Decolourisation modelling utilising response surface methodology (RSM) successfully improved decolourisation even more. RSM resulted in maximal decolourisation of 92.79% using 0.645 g/L ammonium sulphate, pH 8.29, 34.5 °C and 200 ppm RR120.

Download Full-text

Comparison of radical-driven technologies applied for paraben mixture degradation: mechanism, biodegradability, toxicity and cost assessment

Environmental Science and Pollution Research ◽

10.1007/s11356-019-06703-9 ◽

2019 ◽

Vol 26 (36) ◽

pp. 37174-37192 ◽

Cited By ~ 1

Author(s):

Marta Gmurek ◽

João F. Gomes ◽

Rui C. Martins ◽

Rosa M. Quinta-Ferreira

Keyword(s):

Photocatalytic Oxidation ◽

Degradation Mechanism ◽

Transformation Products ◽

Degradation Pathway ◽

Toxicity Assessment ◽

Degradation Efficiency ◽

Lepidium Sativum ◽

Cost Assessment ◽

Aqueous Environment ◽

Photocatalytic Ozonation

AbstractParabens (esters of p-hydroxybenzoic acid) are xenobiosis belonging to endocrine disruptors and commonly used as a preservative in cosmetics, food, pharmaceutical, and personal care products. Their wide use is leading to their appearance in water and wastewater in the range from ng/L to mg/L. In fact, the toxicity of benzylparaben is comparable to bisphenol A. Therefore, it is important to find not only effective but also ecofriendly methods for their removal from aqueous environment since the traditional wastewater treatment approaches are ineffective. Herein, for the first time, such extended comparison of several radical-driven technologies for paraben mixture degradation is presented. The detailed evaluation included (1) comparison of ozone and hydroxyl peroxide processes; (2) comparison of catalytic and photocatalytic processes (including photocatalytic ozonation); (3) characterisation of catalysts using SEM, XRD, DRS, XPS techniques and BET isotherm; (4) mineralisation, biodegradability and toxicity assessment; and (5) cost assessment. O3, H2O2/Fe2+, H2O2/UVC, O3/H2O2, O3/UVA, O3/H2O2/UVA, UVA/catalyst, O3/catalyst and O3/UVA/catalyst were selected from advanced oxidation processes to degrade parabens as well as to decrease its toxicity towards Aliivibrio fischeri, Corbicula fluminea and Lepidium sativum. Research was focused on the photocatalytic process involving visible light (UVA and natural sunlight) and TiO2 catalysts modified by different metals (Ag, Pt, Pd, Au). Photocatalytic oxidation showed the lowest efficiency, while in combining ozone with catalysis and photocatalysis process, degradation efficiency and toxicity removal were improved. Photocatalytic ozonation slightly improved degradation efficiency but appreciably decreased transferred ozone dose (TOD). Results indicate that the degradation pathway is different, or different transformation products (TPs) could be formed, despite that the hydroxyl radicals are the main oxidant.

Download Full-text

Microbial Degradation of Pyridine by Co-culture of Two Newly Isolated Strains, Arthrobacter sp. Strain PDC-1 and Rhodococcus sp. Strain HPD-2

10.21203/rs.3.rs-64856/v1 ◽

2020 ◽

Author(s):

Chunhui Hu ◽

Shuxue Zhao ◽

Lizhong Guo ◽

Hao Yu ◽

Xi Chen

Keyword(s):

Microbial Degradation ◽

Sole Source ◽

Bacterial Consortium ◽

Growth Conditions ◽

Degradation Pathway ◽

Entire Concentration Range ◽

Promising Tool ◽

Pyridine Degradation ◽

River Estuarine ◽

Pyridine Concentration

Abstract Pyridine is one of the most widespread heterocyclic contaminants. Microbial degradation of pyridine seems quite promising for its safety and efficiency. A bacterial consortium, which could use pyridine as the sole source of carbon, nitrogen, was obtained from the petroleum-contaminated soil from Liao River estuarine wetland. Two pyridine degrading strains, designated as PCD-1 and HPD-2, were isolated from the bacterial consortium. PCD-1 was identified as an Arthrobacter , and HPD-2 was identified as the Rhodococcus genus. The effects of pH, temperature, and pyridine concentration were investigated, and the optimum growth conditions for two strains were similar at pH 7.0 and 30°C. The co-culture of the two strains, CoPD, has better degradation efficiency compared with the individual strain. Haldane's inhibitory growth kinetics equation could be fitted to the growth of co-culture CoPD well for the entire concentration range. The kinetic constants obtained were μ max = 0.141 h -1 , K s = 37.9 mg/L, and K i = 3830 mg/L. Co-culture CoPD was able to remove more than 98% pyridine with an initial pyridine concentration of 5,000 mg/L within 120 h. Strain PCD-1 and HPD-2 have a novel pyridine degradation pathway different from the reported pathways. Major intermediates of pyridine degradation by two strains, including 2,5-pyrroldione, maleic semialdehyde, furanone, and butyrolactone, were identified using LC-MS analysis. CoPD is a promising tool for the treatment of wastewater containing pyridine, and this study contributes to the knowledge of the pyridine biodegradation by bacterial consortium.

Download Full-text

Degradation of tetracycline by UV activated monochloramine process: Kinetics, degradation pathway, DBPs formation and toxicity assessment

Chemical Engineering Journal ◽

10.1016/j.cej.2020.125090 ◽

2020 ◽

Vol 395 ◽

pp. 125090 ◽

Cited By ~ 7

Author(s):

Anhong Cai ◽

Jing Deng ◽

Mengyuan Xu ◽

Tianxin Zhu ◽

Shiqing Zhou ◽

...

Keyword(s):

Degradation Pathway ◽

Toxicity Assessment ◽

Process Kinetics

Download Full-text

Effective electrocatalytic elimination of chloramphenicol: Mechanism, degradation pathway, and toxicity assessment

10.21203/rs.3.rs-368864/v1 ◽

2021 ◽

Author(s):

Haiyang Liu ◽

Yihan Lv ◽

Ya-nan Zhang ◽

Yushu Zhang ◽

Jiao Qu ◽

...

Keyword(s):

Indium Tin Oxide ◽

Advanced Oxidation Process ◽

Parent Compound ◽

Degradation Process ◽

Quantitative Structure Activity Relationship ◽

Degradation Pathway ◽

Toxicity Assessment ◽

Degradation Efficiency ◽

Electrocatalytic Degradation ◽

High Efficient

Abstract The residual antibiotics in different environmental media pose a serious threat to human health and the ecosystem. The high-efficient elimination of antibiotics is one of the foremost works. In this study, chloramphenicol (CAP) was eliminated efficiently by electrocatalytic advanced oxidation process with carbon nanotubes/agarose/indium tin oxide (CNTs/AG/ITO) electrode. The influences of different experimental parameters on the degradation efficiency were systematically studied. Under the optimal conditions (4 V potential, 10 wt% CNTs dosage, and pH = 10), the maximum degradation efficiency of CAP (20 mg L− 1) achieved 88% within 180 min. Besides, the electrocatalytic degradation pathway and mechanism for CAP were also investigated, •O2− played a major role in the process of electrocatalytic degradation. Based on the QSAR (quantitative structure-activity relationship) model, the toxicities of CAP and identified intermediates were analyzed. Compared with the parent compound, the maximal chronic toxicity of intermediate ((E)-3-(4-nitrophenyl)prop-1-ene-1,3-diol) for daphnid increased 197-fold. Besides, the hybrid toxicity of the degradation system was further confirmed via disk agar biocidal tests with Escherichia coli ATCC25922, which changed slightly during the degradation process. Based on the above results, it is worth noting that the degradation pathway and toxicity assessment should be paid more attention to the treatment of antibiotic wastewater.

Download Full-text