Mycoremediation of Remazol Brilliant Blue R in greywater by a novel local strain of Aspergillus iizukae 605EAN: optimisation and mechanism study

Abstract

ABSTRACT The decolourisation of Remazol Brilliant Blue R (RBBR) by oxidative enzymes [Laccase (Lac), Manganese peroxidase (MnP), Lignin peroxidase (LiP)], from Aspergillus iizukae EAN605 was optimised as a function of initial substrate concentrations (30−100 mg L−1), incubation period (5–15 days) and pH (5–7). The best operating parameters to achieve the highest removal of RBBR were 57.15 mg 100 mL−1 of RBBR, pH 6 and after 8.55 days where the maximum removal was 78.34% vs. 80.00% (R 2 = 77.9%), Lac 0.22 vs. 0.28 µ mg−1, MnP 0.24 vs. 0.27 µ mg−1 and LiP 14.22 vs. 15.12 µ mg−1 of actual and predicted results, respectively. The surface analysis of A. iizukae EAN605 by field emission scanning electron microscopy suggested that the removal process takes place on the surface of the fungal mycelium cell wall as a result of the presence of Lac enzyme in the inner fungal membrane. Moreover, the phytotoxicity test confirms the absence of the dye toxicity after enzymatic degradation process which indicates the efficiency of A. iizukae EAN605 to minimise the dyes' risk to less than the toxicity level. These findings suggest that A. iizukae EAN605 has a potential for the mycoremediation of dyes in the greywater.