Applications of fungal strains with keratin-degrading and plant growth promoting characteristics

Abstract

Protein hydrolysates (PHs) are organic non-microbial biostimulants having beneficial effects on plants. The study was designed to assess the effects on plants by the applications of PHs obtained from Trichoderma isolates grown on keratin wastes. Trichoderma isolates were characterized for indole-3-acetic acid and siderophores production, activity of lytic enzymes, phosphorous solubilization and inhibition of pathogens growth, using qualitative specific tests. Fungal isolates were cultured on a medium with keratin wastes (wool and feathers) to obtain PHs. Fungal PHs were tested in vivo for plant biostimulant action, as follows: (i) seeds germination test; (ii) activation of plant proton pump; (iii) evaluation of effect on tomato seedling growth. PHs from T. asperellum cultured on feathers medium reached the highest values for all parameters recorded (plant height and diameter, number of leaves and branches), with the exception of those for plant biomass, which were maximum for the wool medium. The metabolites released by keratin degradation under the activity of selected T. asperellum isolate improved crop health and productivity. The use of PHs can be a reasonable solution for the environmental pollution of by-products from the food chain, as well as for the replacement of chemical fertilizers with microbial formulations to stimulate plant growth.