Growth responses of hydroponic green fodder system and Fusarium oxysporum to external supply of mycolytic enzymes applied on seaweed bagasse as carrier

Abstract

High humidity, nutritional and environmental conditions involved in hydroponic green fodder (HGF) production increases fungal contamination risk. Chemical fungicides application is limited because of their toxicity to animals. An alternative biotechnological option is the use of mycolytic enzymes such as chitinase and laminarinase. The goal of the present study was to immobilize chitinase and laminarinase on seaweed bagasse as a carrier in order to increase their action time in HGF system, and compare the effect of those enzymes on Fusarium oxysporum viability and HGF growth. Chitinase and laminarinase immobilization on seaweed bagasse was carried out at 4°C and stirred at 250 rpm. Immobilization was assayed at different incubation times (60, 90, 120, and 180 min). Enzymes immobilization kinetics was monitored from protein quantity balance. Enzymatic activity of chitinase and laminarinase were evaluated. Higher immobilization (65 and 84% for chitinase and laminarinase, respectively) was obtained at 120 min of incubation time. Wheat grains in HGF systems under different treatments were inoculated with F. oxysporum at 2×10 4 spores/ (g of seed). Kinetics of growth measured by height of green shoots, as well as wet mass, dry mass of HGF, and fungal viability after 10 days of germination were evaluated. The higher antifungal effect was observed with immobilized enzymes. It was demonstrated that applied treatments did not affect negatively the fodder growth. Moreover, the bagasse presence can improve HGF height. The obtained results demonstrated that seaweed bagasse may be effectively applied as carrier for biologically active substances in HGF system.