Aptitude of Oxidative Enzymes for Treatment of Wastewater Pollutants: A Laccase Perspective

Abstract

Natural water sources are very often contaminated by municipal wastewater discharges which contain either of xenobiotic pollutants and their sometimes more toxic degradation products, or both, which frustrates the universal millenium development goal of provision of the relatively scarce pristine freshwater to water-scarce and -stressed communities, in order to augment their socioeconomic well-being. Seeing that both regulatory measures, as regards the discharge limits of wastewater, and the query for efficient treatment methods remain unanswered, partially, the prospects of enzymatic treatment of wastewater is advisable. Therefore, a reconsideration was assigned to the possible capacity of oxidative enzymes and the respective challenges encountered during their applications in wastewater treatment, and ultimately, the prospects of laccase, a polyphenol oxidase that oxidizes aromatic and inorganic substrates with electron-donating groups in treatment aromatic contaminants of wastewater, in real wastewater situations, since it is assumed to be a vehicle for a greener community. Furthermore, the importance of laccase-driven catalysis toward maintaining mass-energy balance, hence minimizing environmental waste, was comprehensibly elucidated, as well the strategic positioning of laccase in a model wastewater treatment facility for effective treatment of wastewater contaminants.

Sustainability potentials of novel laccase tinctures from Stenotrophomonas maltophilia BIJ16 and Bordetella bronchiseptica HSO16: From dye decolourization to denim bioscouring

“…Although fungi were the first, and are the most extensively studied for occurrences of multiple laccase genes [20,21], the bacterial laccase-like genes might be more participatory in laccase activity than their fungal confrère . Moreover, the absence of a glycosylated carbohydrate fraction, which is the extant constraint for genetic manoeuvrability and heterologous expression in fungi, makes bacteria most suitable for genetically engineered process and applications pertinent to the overwhelming demands of our present society [22].

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“…Moreover, the step by step decolourization should be monitored for spinoffs, which might serve as valuable startup chemicals for various industrials applications. Given these astronomical qualities of the tinctures, an environomical approach proposed by Unuofin et al [22] should be adopted to enable the simultaneous bulk production of these fine biochemicals as well as the contribution of spent biomass to sustainable agriculture, which will, on the whole, promote environmental sustainability.

Fig. 6Empirical denim bleaching using; (a) Hb16c ( Bordetella bronchiseptica HSO16) laccase, and (b) Berl1 1 b 2 ( Stenotrophomonas maltophilia BIJ16) laccase.

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Catalytic Oxidations in a Bio-Based Economy

“…They are produced, for example, by white rot fungi, and play a key role in the delignification of lignocellulose in vivo (Rochefort et al, 2004). There is considerable commercial interest in the use of laccases in the pulp and paper industry and in waste water remediation in general (Gasser et al, 2014;Singh et al, 2018;Unuofin et al, 2019). They have broad substrate specificity and use dioxygen to oxidize a wide variety of, inter alia, phenols and aromatic amines in vivo.…”

Inhibition in multicopper oxidases: a critical review

“…Since Solomon's influential review of multicopper oxidases and oxygenases in 1996, 1 there have been numerous review articles that cover MCOs. 9,[52][53][54][55][56][57][58] The dozens of reviews that were published from 2017 to the present include both general summaries 13,59,60 and more focused reviews that cover wastewater and soil remediation (including dye and pharmaceutical degradation); 38,39,41,[61][62][63][64][65][66][67][68][69][70][71][72][73][74][75] pulp, paper, lignin and wood processing (including lignin valorization); 67,68,[76][77][78][79][80] chemical synthesis; [80][81][82][83][84] polymer synthesis (including lignin formation); 79,[85][86][87][88]…”