Sustainable Valorization of Chicken Feathers and Grocery Waste as Organic Fertilizer and its Impact on Yield and Quality of Spinach (Spinacia oleracea) Plant

Abstract

ABSTRACT Overproduction of chicken feathers is responsible for serious environmental problems worldwide. The composition of feathers is keratin protein, which is resistant and difficult to monomerize. Utilization of feather waste for biogas and organic fertilizer production can help combat environmental threat and address energy and food shortage crisis. In this study, chicken feathers were hydrolyzed using the native isolated keratinolytic bacterial strain Pseudomonas aeruginosa-C1M. Reactor digestate, a by-product of the production of biogas from hydrolyzate and grocery waste, has been shown to be used as organic fertilizer. A greenhouse study was conducted to investigate the comparative effectiveness of reactor digestate and feather hydrolyzate on the growth of spinach plants. A remarkable increase in agronomic parameters was observed when applying keratin hydrolyzate based fertilizers. Plants treated with dry hydrolyzate showed a 50% increase in leaf width. The plant height, the number of leaves per plant, the root length, the chlorophyll content, the protein content, the biomass and the nutrient content of the spinach plant were also significantly improved by using fertilizers based on keratin hydrolyzate. However, the results using the Pseudomonas aeruginosa-C1M-derived hydrolyzate were more promising and therefore suggest its application as a potential biostimulant in the agricultural industry.