Detoxification of BTEX in a saline environment by Aspergillus niger

Abstract

Abstract BTEX can be found in marine and estuarine waters due to accidental spills of oil and derivatives, as well as in production water and effluents from petrochemical plants. Solutions involving the bioremediation of these compounds in both saline environments and effluents with high salinity are necessary. The halotolerance of Aspergillus niger was tested by subjecting it to a gradual increase in salinity through the sequential addition of NaCl from 2 to 30‰ (v/v). It supported its growth up to 25‰, with a biomass production rate of 0.93 ± 0.11 g/d. The adapted biomass was used in batch reactor assays to test the biodegradation of BTEX (1,500 mg/L). The fungi removed BTEX more rapidly in the presence of 2 g/L of sucrose: benzene (2.20 d-1) > toluene (1.83 d-1) > ethylbenzene (1.12 d-1) > xylene (0.91 d-1). However, even in the absence of sucrose, there was removal in the reactors with fungi: benzene (1.13 d-1) > toluene (0.97 d-1) > ethylbenzene (0.77 d-1) > xylene (0.68 d-1), with higher removal through microbial action (absorption and adsorption). Benzene was the only compound found adsorbed to the mycelium (1.50 ± 0.19 to 13.35 ± 4.72 mg/g of biomass).