Biological pre-treatment of lignocellulose waste for its further application in biogas production

Abstract

The enhancement of phenanthrene catabolism in soils amended with lignocellulosic waste material (spent brewery grains) was investigated. The soils were pre-treated with five white-rot fungi (Phanerochaete chrysosporium, Trametes versicolor, Irpex lateus, Pleurotus ostreatus, and Bjerkandera adusta). The changes in the kinetics of 14C-phenanthrene mineralisation (lag phases, the fastest rates and the overall extents) were measured in the inoculated, PAH-amended soils over time (1–100 d). Changes in the ligninolytic (laccase, lignin peroxidase and manganese peroxidase) and non-ligninolytic (β-glucosidase and phosphatase) enzymatic activities were also assessed. Overall results revealed that the amendment of fungal pre-treated SBG influenced the kinetics of mineralisation of 14C-phenanthrene as well as the enzymatic activities in soils. Soil inoculated with fungal pre-treated SBG caused reductions in lag phases as well as higher rates and extents of 14C-phenanthrene mineralisation in the following trend T. versicolor > B. adusta > P. chrysosporium = P. ostreatus > I. lateus. Furthermore, the extents of mineralisation generally reduced as levels of ligninolytic enzyme decreased, while the non-ligninolytic enzymes increased with soil-PAH contact time in all amendment conditions. These findings provided an insight on the potential of biological pre-treatment of waste materials for enhanced carbon, energy and nutrients on the bioactivities and biodegradation of organic pollutants which may be applicable during in situ remediations of contaminated soil.