Biodegradation and process optimization of phenol and formaldehyde by Aspergillus nomius SGFA1

Abstract

Phenols and formaldehyde are often simultaneously discharged into the environment with sewage, and due to their highly toxic to organisms, few have been reported to be degraded simultaneously. This study investigated the simultaneous biodegradation of phenol and formaldehyde using the highly efficient formaldehyde-degrading fungus Aspergillus nomius SGFA1, which was previously isolated and identified in our laboratory. The response surface methodology was used to optimize the biodegradation conditions of phenol and formaldehyde; the optimum temperature, initial pH, and glucose content were determined to be 28.1 °C, 5.0, and 0.89%, respectively, under which the maximum degradation rates of phenol and formaldehyde reached 89.7% and 85.3%, respectively. Mass balance and stoichiometric analysis revealed 0.26 g⋅g−1 and 0.05 g⋅g−1 conversions of phenol and formaldehyde carbon to biomass, respectively. The degradation pathway demonstrated that phenol hydroxylase (PHE) and formaldehyde dehydrogenase (FALDH) were the key enzymes for phenol and formaldehyde degradation, with enzyme activities reaching maxima of 0.008 and 1.09 U⋅mg−1 at 8 and 6 h, respectively. This study demonstrated the ability of A. nomius SGFA1 to effectively remove phenol and formaldehyde simultaneously, providing new information on the use of microorganisms to reduce environmental pollution.