ReviewLaccases and peroxidases: The smart, greener and futuristic biocatalytic tools to mitigate recalcitrant emerging pollutants
Graphical abstract
Introduction
Over recent decades, the world's population is growing rapidly, which has resulted in numerous ecological impacts with water being one among the foremost affected resources (Peña-Guzmán et al., 2019). The unprecedented rise in population has caused higher consumer demand and has subsequently led to increased ecological pollution. All different kinds of pollution have a profound impact on human health and aquatic organisms, either directly or indirectly. Human-made, industrial, and agricultural disposals play a significant role in causing wastewater pollution. Unfortunately, the numerous types of pollutants which are released in water bodies due to the different agricultural and industrial processes are not completely removed during wastewater treatment processes and therefore have the potential to directly affect humans (Deblonde et al., 2011).
A subclass of organic chemicals that are increasingly being detected in our water bodies have been classified as Emerging Pollutants (EPs), also known as “Contaminants of Emerging Concern” or Micropollutants (MPs) (Teodosiu et al., 2018). These emerging pollutants can be defined as human-made or manufactured synthetic chemicals or naturally occurring materials present in the natural environment without being monitored or regulated in most cases but can adversely affect human health and several other living organisms (Sauvé and Desrosiers, 2014; Bilal et al., 2019a).
They comprise an extensive array of various compounds and their transformation products: pharmaceuticals (e.g. nonsteroidal anti-inflammatory drugs (NSAIDs), analgesics, antibiotics, textile dyes, hormones, and personal care products pesticides) (Lapworth et al., 2012). They are mainly detected in wastewater treatment plants (WWTPs), pharmaceutical production plants, household products, hospitals, graveyards, household products, landfills, aquatic environment, industrial effluents and municipal sewage (Deegan et al., 2011; Ahmed et al., 2017; Bilal et al., 2019b). The concentration of EPs in our environment ranges from ng/L to a few hundred μg/L (Tran et al., 2013; Ahmed et al., 2017). These concentrations are suspected of causing serious ecological threats such as interfering with the endocrine system of high organisms, reproductive impairments, physical abnormalities and congenital disorder in some species, feminization of some fish species and many others (Belhaj et al., 2015). A study in 2011 concluded that the presence of perfluorinated compounds in serum could be correlated to breast cancer risk in Greenlandic Inuit women (Bonefeld-Jorgensen et al., 2011). Additionally, it has been reported that pollutants such as perfluorooctanoate and perfluorooctane sulfonate may be linked to decreased human reproductive abilities (Vélez et al., 2015).
Higher concentrations have been detected for some pollutants such as ciprofloxacin and per- and poly-fluoroalkyl substances (PFAS) as their concentrations reached mg/L and g/L, respectively, in our water supplies (Kelly and Brooks, 2018; Nakayama et al., 2019). Due to the ability of EPs to cause undesirable and deleterious effects on human health and to the ecosystem, they have become the main focus of many academic research groups. For example, a 2012 study found that N, N-Diethyl-meta-toluamide (DEET) can cause an inhibition in the activity of acetylcholinesterase, which is a central nervous system enzyme, in mammals and insects (Corbel et al., 2009). Dealing with EPs requires hard work, as there are many challenges a researcher can face. There is a lack of knowledge about the ecotoxicological information and a deficiency regarding the sampling and analytical techniques (Geissen et al., 2015). Moreover, the long-term effect of EPs on living beings and the environment is not available (Deblonde et al., 2011). Some notable adverse effects of these pollutants are shown in Fig. 1.
The term EPs covers three categories of compounds; the first category includes newly developed compounds that are introduced to the environment, the second category consists of compounds that are presented in the environment for a long time but are only being recognized newly, and the last category includes compounds that are detected since a long time but their significant impact on the environment and human health have been recognized recently such as hormones (Geissen et al., 2015; Bilal et al., 2019c; Rasheed et al., 2018a). More than 1000 EPs have been identified and categorized into different classes, which include pharmaceuticals, personal care products, pesticides, hormones, etc. Table 1 represents an interesting analysis conducted to document physiologically active concentrations of various hormones, antibiotics, and other emerging pollutants in the water bodies in several countries. As can be seen from the table, disturbingly high concentrations of various emerging pollutants are detected in various water bodies. Emerging pollutants can result from agricultural, industrial, household, and hospital discharges. As mentioned previously, there are many sources for the emerging contaminants, but the major source is the WWTP effluents. WWTPs are not designed to completely eliminate and degrade EPs and their metabolites, therefore, they can pass through WWTPs and enter our aquatic environments such as rivers and streams (Petrović et al., 2003; Bilal et al., 2019b). Fig. 2 shows the different sources of emerging pollutants and their transformation to our water supplies.
A wide range of approaches has been developed for the removal of these synthetic pollutants from water bodies, as well as wastewaters thus, reducing their impact on the environment. Various chemical and physical methods have been used for the treatment of contaminated wastewater such as membrane filtration precipitation, flocculation, irradiation, adsorption, and chemical oxidation such as Fenton's oxidation, and AOPs (Ikehata et al., 2006; Comninellis et al., 2008; Deegan et al., 2011; Ahmed et al., 2017; Alneyadi et al., 2018; Barrios-Estrada et al., 2018; Bilal et al., 2018a; Rasheed et al., 2018b; Teodosiu et al., 2018). Furthermore, hybrid systems in which two methods are combined and used have also been developed to enhance the removal efficiency of EPs. Another study demonstrated the photocatalytic degradation of buspirone, an anti-anxiety medicine, using TiO2 and xenon lamp (Calza et al., 2004). Diclofenac is an anti-inflammatory drug used to treat pain and inflammatory diseases. Recently, it has been realized as an ecological pollutant of concern due to its accumulation in the food chain, and identification in drinking water and aquatic systems. It has been detected in our water supplies in different concentrations up to 1.3 μg/L (Ternes et al., 2003). Many AOPs have been applied to diclofenac to evaluate their ability to degrade it effectively. Table 2 summarizes some of the AOPs that were used efficiently to remove various EPs. Other physical methods such as filtration and osmosis are efficient as well, but the cost of materials is expensive compared to the adsorption method (Ali, 2012). Table 3 shows some of the physical methods that have been used previously for the degradation of different emerging pollutants.
Although physical and chemical methods are widely used and these methods can work effectively, they have several potential limitations, such as overall high cost, inefficiency, production of high sludge, and formation of toxic side products. Hence, it is well accepted that there is a dire need to find better, novel, and more environmentally safe approaches for wastewater remediation. Biological (specifically microbial and enzyme-based) approaches for degrading various kinds of organic pollutants are a promising new area of research in water treatment (Al-Maqdi et al., 2017; Bilal et al., 2017a). Biodegradation or bioremediation has been successfully used for the removal of EPs from wastewaters. In this process, microorganisms such as bacteria, fungi or yeasts (or enzymes from these microorganisms) are used for the removal of organic chemicals from water bodies. In biodegradation, the microorganisms utilize the pollutant as a substrate and induce enzymes, then the pollutants are enzymatically converted into smaller molecules that are usually less toxic (Tran et al., 2013; Ahmed et al., 2017). Biodegradation processes have many advantages compared to the physiochemical techniques as they are safer, less disruptive, less expensive, require lower energy employment, considered as a green catalysis processes and can be used with pollutants having very low concentrations, which cannot be achievable using physiochemical techniques (Rauf and Ashraf, 2012; Al-Maqdi et al., 2017; Holanda et al., 2019). A major drawback of biological treatments is that they require a longer time, and the microorganisms may not be able to survive and grow under harsh and adverse environmental conditions (Rauf and Ashraf, 2012; Al-Maqdi et al., 2017).
In this review, following a brief overview of in-practice physical and chemical treatment methods, numerous oxidoreductases (laccases, SBP, HRP, LiP, MnP, and CPO) have been discussed with recent updates and suitable examples as a greener oxidation route towards efficient and effective removal or degradation of EPs/MPs. The later part of the work is focused on the identification of transformation products, eco-toxicity, and estrogenicity evaluation of EPs/MPs. Finally, practical challenges and perspectives for engineering robust biocatalysts are given that can pave the way for future studies.
Section snippets
Enzymatic biodegradation — towards greener oxidation route
The biological approach that uses oxidoreductase enzymes (such as peroxidases) for pollutant degradation is a relatively new and promising research area. Numerous enzyme systems have been employed for the efficient degradation of diverse organic pollutants and have shown to oxidize and degrade the pollutants into smaller intermediates. Using enzyme-based treatments offer many advantages such as the ability to operate at high and low concentrations of pollutants, reduced amount of sludge
Identification of transformation products and toxicity evaluation
Enzymes cause the degradation of various environmental pollutants by different pathways resulting in the generation of various metabolic intermediates and end products during the biocatalytic reaction. In the majority of the degradation studies, scientists and researchers principally focus on the parent compounds disappearance rather than the scrutinization of transformation pathways, intermediate metabolites, and evaluation of toxicity and estrogenicity of the transformed products (Becker et
Practical challenges and perspectives for engineering robust biocatalysts
In spite of the plentiful studies documenting biocatalytic proficiency and versatility for the transformation and degradation of an array of recalcitrant polluting compounds such as endocrine disruptors, xenobiotics, the application of oxidoreductases has not been endeavored at large scale. Ayala et al. (2008) appraised the current challenges that come across during the real-time application of peroxidases. Notable protein-engineering bottlenecks that have been realized include 1) augmentation
Concluding remarks
Various wastewater treatment technologies are discussed with a particular emphasis on laccases and peroxidases based enzymatic approach for the degradation and detoxification of emerging contaminants. Based on the extensive literature survey and our research struggles, this study accentuated that the biocatalytic approach has received unprecedented importance in mitigating an array of emerging pollutants typically present in wastewater effluents. So far, multiple controlled studies have been
Declaration of competing interest
We do not have any conflicting, competing, and financial interests in any capacity.
Acknowledgments
The authors are grateful to their representative universities for providing resources for this work. Partial funding for RM was provided by the College of Graduate Studies, UAE University.
References (173)
- et al.
Retention of emerging micropollutants from UP water and a municipal secondary effluent by ultrafiltration and nanofiltration
Chem. Eng. J.
(2010) - et al.
Progress in the biological and chemical treatment technologies for emerging contaminant removal from wastewater: a critical review
J. Hazard. Mater.
(2017) - et al.
Optimization of decolorization of methylene blue by lignin peroxidase enzyme produced from sewage sludge with Phanerocheate chrysosporium
J. Hazard. Mater.
(2009) - et al.
Detoxification and degradation of sulfamethoxazole by soybean peroxidase and UV+ H2O2 remediation approaches
Chem. Eng. J.
(2018) - et al.
Differential enzymatic degradation of thiazole pollutants by two different peroxidases–a comparative study
Chem. Eng. J.
(2016) - et al.
Behavior of endocrine disrupting chemicals in leachate from MSW landfill sites in Japan
Waste Manag.
(2004) - et al.
Purification and characterization of manganese peroxidases from native and mutant Trametes versicolor IBL-04
Chin. J. Catal.
(2016) - et al.
Natural and synthetic hormone removal using the horseradish peroxidase enzyme: temperature and pH effects
Water Res.
(2006) - et al.
Removal of estrogenic activity of natural and synthetic hormones from a municipal wastewater: efficiency of horseradish peroxidase and laccase from Trametes versicolor
Chemosphere
(2008) - et al.
Influence of seasonal climate differences on the pharmaceutical, hormone and personal care product removal efficiency of a drinking water treatment plant
Chemosphere
(2013)
Screening level mixture risk assessment of pharmaceuticals in STP effluents
Water Res.
Potentialities of active membranes with immobilized laccase for bisphenol A degradation
Int. J. Biol. Macromol.
Redox properties of heme peroxidases
Arch. Biochem. Biophys.
Removal of antibiotics in wastewater by enzymatic treatment with fungal laccase – degradation of compounds does not always eliminate toxicity
Bioresour. Technol.
Fate of selected estrogenic hormones in an urban sewage treatment plant in Tunisia (North Africa)
Sci. Total Environ.
Persistence and impact of steroidal estrogens on the environment and their laccase-assisted removal
Sci. Total Environ.
Chemical, physical, and biological coordination: an interplay between materials and enzymes as potential platforms for immobilization
Coord. Chem. Rev.
Horseradish peroxidase-assisted approach to decolorize and detoxify dye pollutants in a packed bed bioreactor
J. Environ. Manag.
Development of horseradish peroxidase-based cross-linked enzyme aggregates and their environmental exploitation for bioremediation purposes
J. Environ. Manag.
Enhanced bio-catalytic performance and dye degradation potential of chitosan-encapsulated horseradish peroxidase in a packed bed reactor system
Sci. Total Environ.
Peroxidases-assisted removal of environmentally-related hazardous pollutants with reference to the reaction mechanisms of industrial dyes
Sci. Total Environ.
Emerging contaminants of high concern and their enzyme-assisted biodegradation–a review
Environ. Int.
Biocatalytic degradation/redefining “removal” fate of pharmaceutically active compounds and antibiotics in the aquatic environment
Sci. Total Environ.
Mitigation of bisphenol a using an array of laccase-based robust bio-catalytic cues–a review
Sci. Total Environ.
Persistence of pesticides-based contaminants in the environment and their effective degradation using laccase-assisted biocatalytic systems
Sci. Total Environ.
Hazardous contaminants in the environment and their laccase-assisted degradation–a review
J. Environ. Manag.
Effect of iron ion on doxycycline photocatalytic and Fenton-based autocatatalytic decomposition
Chemosphere
Elimination of endocrine disrupting chemicals nonylphenol and bisphenol A and personal care product ingredient triclosan using enzyme preparation from the white rot fungus Coriolopsis polyzona
Chemosphere
Removal of an analgesic using activated carbons prepared from urban and industrial residues
Chem. Eng. J.
The photocatalytic process as a tool to identify metabolitic products formed from dopant substances: the case of buspirone
J. Pharm. Biomed. Anal.
Description of a versatile peroxidase involved in the natural degradation of lignin that has both manganese peroxidase and lignin peroxidase substrate interaction sites
J. Biol. Chem.
Application of high intensity UVC-LED for the removal of acetamiprid with the photo-Fenton process
Chem. Eng. J.
Enzymatic treatment of methyl orange dye in synthetic wastewater by plant-based peroxidase enzymes
Journal of Environmental Chemical Engineering
Pharmaceuticals occurrence in a WWTP with significant industrial contribution and its input into the river system
Environmental pollution
Fungal peroxidases: molecular aspects and applications
J. Biotechnol.
Emerging pollutants in wastewater: a review of the literature
Int. J. Hyg. Environ. Health
Simultaneous removal and degradation characteristics of sulfonamide, tetracycline, and quinolone antibiotics by laccase-mediated oxidation coupled with soil adsorption
Journal of hazardous materials
Ecotoxicological impact of pharmaceuticals found in treated wastewaters: study of carbamazepine, clofibric acid, and diclofenac
Ecotoxicol. Environ. Saf.
Lignin peroxidase efficiency for methylene blue decolouration: comparison to reported methods
Dyes Pigments
Adsorption and removal of tetracycline antibiotics from aqueous solution by graphene oxide
J. Colloid Interface Sci.
Comparison of drinking water pollutant removal using a nanofiltration pilot plant powered by renewable energy and a conventional treatment facility
Desalination
Emerging pollutants in the environment: A challenge for water resource management
International Soil and Water Conservation Research
Review: lignin conversion by manganese peroxidase (MnP)
Enzym. Microb. Technol.
Study of biodegradation of chloramphenicol by endophytic fungi isolated from Bertholletia excelsa (Brazil nuts)
Biocatal. Agric. Biotechnol.
Emerging pollutants and plants–metabolic activation of diclofenac by peroxidases
Chemosphere
Occurrence and removal of pharmaceuticals and hormones through drinking water treatment
Water Res.
Elimination and detoxification of triclosan by manganese peroxidase from white rot fungus
J. Hazard. Mater.
Elimination and detoxification of fungicide miconazole and antidepressant sertraline by manganese peroxidase-dependent lipid peroxidation system
Int. Biodeterior. Biodegradation
Degradation of carbamazepine by Trametes versicolor in an air pulsed fluidized bed bioreactor and identification of intermediates
Water research
Biocatalytic degradation of carbamazepine with immobilized laccase-mediator membrane hybrid reactor
J. Membr. Sci.
Cited by (207)
Construction of a continuous packed bed laccase reactor for the elimination of tetracyclines in seawater
2024, Journal of Environmental Chemical EngineeringStable and selective multi-porous nickel nanoparticles catalysts for hydrocracking of dibenzyl ether supported by DFT studies
2024, Journal of Saudi Chemical SocietyPleurotus ostreatus and Lentinus sajor-caju laccases for sulfamethoxazole biotransformation: Enzymatic degradation, toxicity and cost analysis
2024, Journal of Water Process EngineeringMXene-based adsorbent materials for pollutants removal from water: Current challenges and future prospects
2024, Inorganic Chemistry CommunicationsRecent advances in laccase activity assays: A crucial challenge for applications on complex substrates
2024, Enzyme and Microbial Technology