Mineralization of mono‐nitrophenols by Bjerkandera adusta and Lentinus squarrosulus and their extracellular ligninolytic enzymes

Abstract

Nitroaromatic compounds constitute a major class of widely distributed environmental contaminants. Fifty fungal strains were screened for their potential to tolerance with 2-nitrophenol, 3-nitrophenol and 4-nitrophenol on solid medium supplemented with 2% malt extract (MEA). Growth rate (mm/day) was determined at three concentrations (0.25, 0.5 and 1 mM) of all the three nitrophenols. From the fifty fungal strains only Bjerkandera adusta and Lentinus squarrosulus were able to tolerate all the three nitrophenols (NPs). These white-rot fungi (WRF) were chosen for liquid medium studies for the mineralization of mono-nitrophenols and ligninolytic enzyme activity at 0.25 mM concentration. Both varieties completely removed 2-NP and 3-NP while 4-NP was hard to mineralize. AAO (Aryl Alcohol Oxidase) is the main oxidase enzyme in B. adusta while laccase plays important role in L. squarrosulus. MnP (Manganese peroxidase) is the main peroxidase enzyme in both varieties. These fungal strains were capable to degrade nitrophenols and could be used for bioremediation applications on large scale.