Laccases to take on the challenge of emerging organic contaminants in wastewater

Abstract

The removal of emerging organic contaminants from municipal wastewater poses a major challenge unsatisfactorily addressed by present wastewater treatment processes. Enzyme-catalyzed transformation of emerging organic contaminants (EOC) has been proposed as a possible solution to this major environmental issue more than a decade ago. Especially, laccases gained interest in this context in recent years due to their broad substrate range and since they only need molecular oxygen as a cosubstrate. In order to ensure the stability of the enzymes and allow their retention and reuse, either immobilization or insolubilization of the biocatalysts seems to be the prerequisite for continuous wastewater treatment applications. The present review summarizes the research conducted on EOC transformation with laccases and presents an overview of the possible immobilization techniques. The goal is to assess the state of the art and identify the next necessary steps that have to be undertaken in order to implement laccases as a tertiary wastewater treatment process in sewage treatment plants.

Laccases: Production, Expression Regulation, and Applications in Pharmaceutical Biodegradation

“…Examples of environmentally important enzymes comprise hydrolases, laccases, lyases, peroxidases, tyrosinases, and P450 cytochrome monooxidases (Demarche et al, 2012; Yang et al, 2013a; Rao et al, 2014; Kües, 2015; Yadav and Yadav, 2015; Martinkova et al, 2016). The ability of laccases to effectively degrade and detoxify a variety of persistent organic pollutants (POPs) has received considerable attention in the field of bioremediation (Majeau et al, 2010; Strong and Claus, 2011; Gasser et al, 2014; Viswanath et al, 2014; Catherine et al, 2016), and laccases can also be used in enzymatic biosensors for environmental pollution monitoring (Rao et al, 2014). A summary of environmental contaminants as laccase substrates from published research in the year 2016 is provided in Table 3.…”

“…A summary of environmental contaminants as laccase substrates from published research in the year 2016 is provided in Table 3. The contaminants investigated include dyestuffs (Singh R. L. et al, 2015; Sen et al, 2016), polycyclic aromatic hydrocarbons (PAHs) (Librando and Pappalardo, 2013), endocrine disrupters (Cabana et al, 2007; Husain and Qayyum, 2012; Gasser et al, 2014), and pesticides (Maqbool et al, 2016). …”

“…Laccases can be employed for their removal (Gasser et al, 2014). Laccases have been used in PPCPs as an ingredient; many products generated by laccases have antimicrobial, anticancer, antioxidant, detoxifying, or other activities (Senthivelan et al, 2016; Upadhyay et al, 2016).…”

Ligninolytic enzymes: Versatile biocatalysts for the elimination of endocrine‐disrupting chemicals in wastewater

“…The catalytic efficiency of laccases is dependent on the redox potential of the active site type 1 (T1) copper ion (Eldridge et al., ), where substrate oxidation occurs in a one‐electron reaction. Usually, microbial laccases exhibit higher redox potential than laccases of plant origin (Gasser et al., ). This indicates that laccases from microbes may probably have higher activity and catalytic efficiency when compared to plant laccases.…”

Potentiality of a ceramic membrane reactor for the laccase-catalyzed removal of bisphenol A from secondary effluents

“…An external filtration module comprising a TiO 2 ceramic membrane was used to retain the enzyme in the system. Although the use of laccase to remove micropollutants from aqueous systems has been reported in several studies (recently reviewed by Gasser et al (2014)), in most of these studies, the enzymatic degradation was performed in buffer solutions, under favorable pH values that are not encountered in WWTPs and high concentrations of the target pollutants.…”