Réhabilitation de sols industriels contaminés aux hydrocarbures par mycoremédiation

Abstract

Polycyclic Aromatic Hydrocarbons (PAH) and alkanes (C10-C50) are common soil contaminants. The Ministry of Sustainable Development, Environment and the Fight Against Climate Change of Quebec determines acceptable levels of soil contamination based on the mass of contaminants in soil and land use. There are currently 4 195 contaminated sites in Quebec. Brownfields are a common type of contaminated site classified by the adsorption of contaminants to the micropores making them unavailable to microorganisms. Different technologies either remove, stabilise or degrade soil contaminants. Certain fungi produce enzymes capable of degrading organic contaminants. Mycoremediation is based on the degradation of the contaminants through direct contact with the enzymes produced by fungi. Laccase, produced by Pleurotus ostreatus, degrades PAH. Lipase, produced by Mucor rouxii, Aspergillius versicolor et Penicillium simplicissimum, degrades C10-C50. This study explores the degradative capacity of these solid-state mushrooms homogenised with brownfields contaminated soil. Specifically, degradation rates and the presence of enzymes will be analysed. Initially, P. ostreatus obtained the best results, with a maximal degradative capacity of 51 % for PAH and 45 % for C10-C50. Subsequent experiments were done to attempt maximizing this degradative capacity. These studies found that the fungi should not be disturbed once mycoremediation has begun. Disturbances, which include humidifying the surface and homogenisation negatively affect the degradative capacity. Overall, 71 % (PAH) and 86 % (C10-C50) of the trials decreased in contamination after 21 days. This study is the first to demonstrate the role of P. ostreatus in the degradation of C10-C50. Future studies should develop fundamental knowledge on the secretion of the enzymes by the mushroom and the limits in industrial-scale mycoremediation.

Date	20 Jul 2017
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Frédéric Monette (Supervisor)