Abstract

The versatile nature of the commercial mushroom, Pleurotus ostreatus (Jacq.: Fr.) Kumm., provides basis for continued exploration of its biochemical processes during solid state fermentation on various lignocellulosic biomass as potential substrates. As a fungal organism, P. ostreatus feeds on lignocellulose by secreting various extracellular enzymes responsible for breaking down this organic polymer into smaller and simple compounds that the hyphae can absorb to develop into mycelia. In this study, P. ostreatus was assessed for its ability to grow on Eichhornia crassipes (Mart.) Solms-Laubach., or water hyacinth biomass and possibly, utilizing it as a substrate. E. crassipes is an aquatic herbaceous plant, often branded as the world’s worst aquatic weed due to its invasive aggression, negative impact onto the aquatic ecosystems, and the cost usually associated with its control. When cultured onto the biomass of this nuisance weed followed by assessment by the agar plate-based clearing assay method and spectrophotometry, P. ostreatus demonstrated its practical ability to secrete cellulases, xylanases, pectinases, lignin peroxidases and laccases, thus showing its physiological capabilities to optionally utilize E. crassipes as a substrate. If properly optimized, this approach can be remarkably used as a sustainable and cost-effective strategy to manage E. crassipes in Zimbabwe.

Key words: Pleurotus ostreatus, Eichhornia crassipes, lignocellulosic biomass, lignocellulolytic enzymes, cellulases, xylanases, pectinases, lignin peroxidases, laccases.