Phytoremediation of metal-contaminated soils by the hyperaccumulator canola (Brassica napus L.) and the use of its biomass for ethanol production

Abstract

This study evaluates the phytoremediation potential of canola biomass, which was grown on soils contaminated by several metals. The increase in metal concentration was measured in different parts of the growing biomass. Nearly 95 mg zinc/kg soil of the zinc supplied to the soil accumulated within the roots of canola. To test the suitability of the canola biomass for bioethanol production, a saccharification was performed after phytoextraction of metals. Armillaria gemina and Pholiota adiposa were co-cultured to obtain a highly active lignocellulase cocktail. Saccharification yields (SY) of 71.8% and 74.4% were obtained with biomass contaminated with nickel and copper, respectively. Under similar conditions, Celluclast® 1.5 L in combination with commercial β-glucosidase resulted in a SY of 73.4%. Fermentation using the hydrolysate of canola biomass used in the phytoremediation yielded 68.9% of bioethanol. To our knowledge, this is the first study where canola biomass used for phytoremediation was tested for bioethanol production through saccharification.