Understanding the factors controlling the removal of trace organic contaminants by white-rot fungi and their lignin modifying enzymes: A critical review

Abstract

White-rot fungi (WRF) and their lignin modifying enzymes (LME) can degrade a wide range of trace organic contaminants (TrOC), which are suspected to cause adverse health effects in humans and other biota. Recent studies have successfully applied either whole-cell WRF or their extracellular culture extract to remove TrOC from the aqueous phase. TrOC removal by a WRF system is dependent on a range of factors including molecular structure of the TrOC, fungal species and their specific LME, culture medium composition, and methods to enhance fungal degradation capacity; however, the specific relationships between these factors have not been systematically delineated. The aim of this review paper is to fill this important gap in the literature by critically analysing the ability of WRF and their LME specifically to remove TrOC. Mechanisms and factors governing the degradation of TrOC by WRF and their LME are reviewed and discussed. © 2013 Elsevier Ltd. AbstractWhite-rot fungi (WRF) and their lignin modifying enzymes (LME) can degrade a wide range of trace organic contaminants (TrOC), which are suspected to cause adverse health effects in humans and other biota. Recent studies have successfully applied either whole-cell WRF or their extracellular culture extract to remove TrOC from the aqueous phase. TrOC removal by a WRF system is dependent on a range of factors including molecular structure of the TrOC, fungal species and their specific LME, culture medium composition, and methods to enhance fungal degradation capacity; however, the specific relationships between these factors have not been systematically delineated. The aim of this review paper is to fill this important gap in the literature by critically analysing the ability of WRF and their LME specifically to remove TrOC. Mechanisms and factors governing the degradation of TrOC by WRF and their LME are reviewed and discussed.

Sulfamethoxazole and isoproturon degradation and detoxification by a laccase-mediator system: Influence of treatment conditions and mechanistic aspects

“…Micropollutant oxidation assays were performed at different pH values (3)(4)(5)(6)(7)(8)(9) in citrate or phosphate buffers (30-40 mM) containing the pollutant at around 100 M (20-25 mg l −1 ) and variable concentrations of mediator (10-1000 M). Batch reactions were conducted in 2-ml glass vials containing 1 ml of an oxygensaturated reaction mixture.…”

“…Bio-oxidation of these pollutants, catalyzed by oxidative enzymes such as laccase, is a potentially attractive treatment option [5]. Laccases, multi-copper oxidases produced by many fungi and bacteria, can oxidize a wide range of pollutants containing phenol and aniline moieties, including several pharmaceuticals and pesticides, requiring only oxygen as a co-substrate [6].…”

The effects of mediator and granular activated carbon addition on degradation of trace organic contaminants by an enzymatic membrane reactor

“…This HAT mechanism has been implicated for the oxidation of resistant species such as non-phenolic compounds. However, to date the use of mediators to improve TrOC removal has been reported in mostly batch test studies (Yang et al, 2013a).…”

“…The substrate range of laccase can be expanded in the presence of small molecular weight redox-mediators that act as an 'electron shuttle' between the enzyme and the target compounds. The degree of enhancement depends predominantly on the type of mediator and TrOC structure (Yang et al, 2013a). However, TrOC degradation by the mediator-enhanced laccase system has been studied almost exclusively in batch tests.…”

Removal of trace organic contaminants by an MBR comprising a mixed culture of bacteria and white-rot fungi

“…Thus, the removal efficiency of TrOC by CAS can vary significantly . Due to the limitations of TrOC removal by the bacteria-dominated CAS process, several small-scale batch studies have been conducted to explore the application of white-rot fungal bioremediation (Yang et al, 2013b). White-rot fungi possess one or more extracellular enzymes including lignin peroxidases However, a systematic assessment of the relative performance of fungus and activated sludge, and the implications of combining them in a continuous flow system is absent from the literature.…”