Potential of the salt‐tolerant laccase‐producing strain Trichoderma viride Pers. NFCCI‐2745 from an estuary in the bioremediation of phenol‐polluted environments

Abstract

Industrialization causes the generation of phenolic pollutants in the environment. The ability of laccases to oxidize phenolic compounds and reduce molecular oxygen to water has led to intensive studies on these enzymes. Although salt-tolerant fungi are potential sources of enzymes for industrial applications, they have been inadequately explored for laccase production. This study describes the isolation of a salt- and phenol-tolerant strain of Trichoderma sp. with the ability to produce laccase, and thus with the potential for industrial applications. The coconut husk retting ground in the estuaries of Kerala, India, a saline environment highly polluted with phenolic compounds, was selected for isolating the fungus. Enhanced laccase production was observed at 5-10 ppt salinity. The organism could grow even at 30 ppt salinity with reduced biomass production and laccase secretion. The optimum concentration of different phenolic compounds for enhanced laccase secretion ranged between 20 and 80 mg L(-1) . As the concentration of phenolic compounds increased beyond 200 mg L(-1) , the enzyme activity decreased and was completely inhibited at 800 mg L(-1) . The tolerance of Trichoderma viride Pers. NFCCI-2745 to salinity and various phenolic compounds can be utilized in the bioremediation of highly saline and phenolic compound-rich industrial effluents.

Characteristics of phenol degradation in saline conditions of a halophilic strain JS3 isolated from industrial activated sludge

“…However, higher phenol concentration did harm to the fungi and the pollutant removal efficiency fluctuated when phenol concentration was up to 1000 mg/L with certain inoculating quantity (data not shown). This might reflect the substrate inhibition of fungal growth due to extension of the lag phase, which was also observed on Trichoderma viride Pers (Divya et al, 2014). The strain reached the highest reduction rate and phenol concentration decreased from the initial 500 mg/L to nearly 0 mg/L by the end of 34 h. During this period, the phenol concentration plunged from 275.5 to 17.3 mg/L in 4 h, which was in accordance with the significant increase of OD 600 between 30 h and 34 h. In contrast, Kobayashi et al (2012) have found that the maximum phenol degradation rate of Acinetobacter sp.…”

Diverse Metabolic Capacities of Fungi for Bioremediation

“…Several factors have been proposed for enhancing the bioremediation of toxic and persistent organic pollutants by applying fungi. The attribute of marine fungi for producing laccase tolerant to high salinity and phenolics was aptly exploited by Divya et al [38] in case of Trichoderma viride Pers NFCCI-2745 isolated from an estuary polluted with phenolics. Similar applications of enzyme mediated bioremediation was demonstrated for decolorizing Remazol Brilliant Blue-R dye using three basidiomycetes isolated from marine sponges [39], and anthraquinone dye Reactive Blue 4 by C. unicolor, a marine white-rot basidiomycete.…”

Trichoderma-based Products and their Widespread Use in Agriculture

“…They are also recognized for their potential in bio-and phytobioremediation of toxic compounds by degrading pollutants particularly in the soil environment [86][87][88]. The versatility of Trichoderma spp.…”