Bacteria-white-rot fungi joint remediation of petroleum-contaminated soil based on sustained-release of laccase

Abstract

In this work, a new model of a bioremediation system for petroleum-contaminated soil was developed which had a TPH degradation rate of 57.72 ± 5.55% after 30 days of remediation. In this system, petroleum-degrading bacteria combined with white-rot fungi were applied to the remediation of petroleum-contaminated soil. Instead of spraying a fungal suspension, through solid-state fermentation (SSF), the white-rot fungi first formed a remediation material which could continuously secrete key enzymes under special stimulation, which could then be used in the remediation after reaching the steady structure of a white-rot fungi carrier (after SSF). The white-rot fungi remediation material was designed to be placed inside or on the surface of the soil, and it degraded the petroleum hydrocarbons simultaneously with the bacteria in the soil. The enzyme secretions of white-rot fungi during the SSF and fungi remediation material during the petroleum-contaminated soil remediation were analysed. In addition, sand, straw and biosurfactants were added to assist the bioremediation to optimize the bacteria-white-rot fungi joint remediation system. Orthogonal experiments were also performed to study the effect of different factors in the remediation.