Rapeseed meal: an agro-waste for cheap/low cost laccase production

Abstract

Rapeseed meal (RM) is an abundant and cheap by-product of oil extraction process. RM is a rich source of nitrogen, carbon, and minerals. Thanks to these features, RM has a striking potential for eco-friendly production of high value products in biotechnological processes. In this study, the possibility of using a low-cost medium based on the water soluble fraction of RM for laccase production by the fungus Pleurotus ostreatus has been evaluated and compared with the use of synthetic complex media. RM-based medium (RMM) led to extracellular laccase production comparable to that obtained in the presence of synthetic media. Moreover, the use of a raw material highly reduced the production costs. To further reduce cost and improve activity production the effect of the addition of nitrogen source, pure aromatic compounds and lignosulphonate, a low cost by-product of wood based industries, was evaluated. The optimized medium led to a laccase production level of more than 100,000 U/L at a cost of about 0.19*10-3 cent /U. The obtained results demonstrate the effective recycle of a waste to produce an industrially relevant enzyme.