Oxidation of Flame Retardant Tetrabromobisphenol A by a Biocatalytic Nanofiber of Chloroperoxidase

Biological oxidation methods for the removal of organic and inorganic contaminants from wastewater: A comprehensive review

Enzyme-based bioremediation is a simple, cost-effective, and environmentally friendly method for isolating and removing a wide range of environmental pollutants. This study is a comprehensive review of recent studies on the oxidation of pollutants by biological oxidation methods, performed individually or in combination with other methods. The main bio-oxidants capable of removing all types of pollutants, such as organic and inorganic molecules, from fungi, bacteria, algae, and plants, and different types of enzymes, as well as the removal mechanisms, were investigated. The use of mediators and modification methods to improve the performance of microorganisms and their resistance under harsh real wastewater conditions was discussed, and numerous case studies were presented and compared. The advantages and disadvantages of conventional and novel immobilization methods, and the development of enzyme engineering to adjust the content and properties of the desired enzymes, were also explained. The optimal operating parameters such as temperature and pH, which usually lead to the best performance, were presented. A detailed overview of the different combination processes was also given, including bio-oxidation in coincident or consecutive combination with adsorption, advanced oxidation processes, and membrane separation. One of the most important issues that this study has addressed is the removal of both organic and inorganic contaminants, taking into account the actual wastewaters and the economic aspect.

Green remediation potential of immobilized oxidoreductases to treat halo-organic pollutants persist in wastewater and soil matrices - A way forward

The alarming presence of hazardous halo-organic pollutants in wastewater and soils generated by industrial growth, pharmaceutical and agricultural activities is a major environmental concern that has drawn the attention of scientists. Unfortunately, the application of conventional technologies within hazardous materials remediation processes has radically failed due to their high cost and ineffectiveness. Consequently, the design of innovative and sustainable techniques to remove halo-organic contaminants from wastewater and soils is crucial. Altogether, these aspects have led to the search for safe and efficient alternatives for the treatment of contaminated matrices. In fact, over the last decades, the efficacy of immobilized oxidoreductases has been explored to achieve the removal of halo-organic pollutants from diverse tainted media. Several reports have indicated that these enzymatic constructs possess unique properties, such as high removal rates, improved stability, and excellent reusability, making them promising candidates for green remediation processes. Hence, in this current review, we present an insight of green remediation approaches based on the use of immobilized constructs of phenoloxidases (e.g., laccase and tyrosinase) and peroxidases (e.g., horseradish peroxidase, chloroperoxidase, and manganese peroxidase) for sustainable decontamination of wastewater and soil matrices from halo-organic pollutants, including 2,4-dichlorophenol, 4-chlorophenol, diclofenac, 2-chlorophenol, 2,4,6-trichlorophenol, among others.

Monitoring and Ecotoxicity Assessment of Emerging Contaminants in Wastewater Discharge in the City of Prague (Czech Republic)

Emerging contaminants (ECs) are not monitored nor regulated consistently, but may have negative effects on human health and ecosystem balance. Although pharmaceuticals and personal care products are among the main ECs found in surface and wastewater, their toxicity and fate are currently not sufficiently studied. In this study, we analyzed for the first time a group of 46 ECs in the secondary effluent of the wastewater treatment plants (WWTP) of Prague. Thirty-seven compounds were identified in the discharge to surface water. Three compounds had no toxicology information on Artemia salina: furosemide, hydrochlorothiazide, and tramadol. We performed acute toxicity (LC50) tests and enzyme assays after 24 and 48 h at room temperature and 28 °C for these three compounds. LC50 ranged from 225.01 mg/L for furosemide, the most toxic, up to above 14,000 mg/L for tramadol. Changes in enzymatic activity for GST, GPx, AChE, and LDH when A. salina were exposed to LC25 for each contaminant were conspicuous and significant in a contaminant-, exposure time-, and temperature-dependent manner. These biochemical markers complement the toxicity profile of these contaminants in aquatic ecosystems and highlight the need for further research on other ECs and their implications, and the regulations required to protect human and ecological health.