The potential use of Lentinus edodes to manage and control water hyacinth in Zimbabwe

The rapid expansion and reproduction of certain plant species represents one of the biggest problems in aquatic environments, ranging from eutrophication to the limited availability of water for human consumption. Among these plants is water hyacinth (Eichhornia crassipes), a herbaceous hydrophyte often branded the world’s worst aquatic weed due to its invasive aggression, negative impact on aquatic environments, and the cost usually associated with its management. Water hyacinth is a biomass, typically rich in lignocellulosic material and making it a potential raw material for the synthesis of products of industrial and domestic interest; e.g. edible fungi. Among the commonly known edible fungi is Lentinus edodes, a commercial mushroom whose versatile nature as a white rot fungus provides basis for the continued exploration of its biochemical processes during solid state fermentation on various lignocellulosic biomass as potential substrates. The fungus naturally feeds on lignocellulose by secreting various extracellular enzymes responsible for breaking down this organic polymer into simple soluble molecules that the hyphae can absorb and develop into mycelia. In this study, L. edodes was assessed for its ability to grow on water hyacinth and possibly utilizing it as a substrate. When cultured onto this noxious biomass followed by assessment by agar plate-based clearing assay and spectrophotometry, the fungus demonstrated its ability to secrete cellulases, xylanases, pectinases, peroxidases and laccases, thus showing its capabilities to physiologically utilize this hydrophyte as a substrate. If properly optimized, this approach can be remarkably used as a sustainable way to control water hyacinth in Zimbabwe.   Key words: Lentinus edodes, water hyacinth, lignocellulosic biomass, lignocellulolytic enzymes, cellulases, xylanases, pectinases, lignin peroxidases, laccases.