Evaluation of feather hydrolysate‑mediated silver nanoparticles as biofertilizers for the enhancement of vegetative growth and nutraceutical properties of vegetables

Abstract

Agricultural production currently depends largely on the use of synthetic fertilizers to boost the production of staple and healthy foods. However, their excessive and inappropriate use had been found expensive and detrimental to the ecosystem. Thus, development of alternative bio-based fertilizers in the form of nanomaterials to improve the yield and nutraceutical properties of crops in a sustainable manner is encouraged. This study therefore reports the biosynthesis of silver nanoparticles (FH-AgNPs) using feather hydrolysates (FH) obtained after chicken feather degradation by keratinolytic Bacillus safensis LAU 13 and Aquamicrobium defluvii FH 20. Phytostimulatory effects of the biogenic AgNPs on Corchorus olitorius, Amaranthus caudatus and Celosea argentea cultivated in soil treated with 50–150 μg/ml FH-AgNPs were investigated compared to NPK fertilizer (15–15-15) and water as positive and negative controls, respectively. Vegetables grown with 150 μg/ml of both FH-AgNPs demonstrated 1–1.58-fold improvement in seed germination, shoot height, root length, leaf size, chlorophyll contents and other growth parameters compared to their controls. Hydrogen peroxide and DPPH radicals scavenging activities of the FH-AgNPs-fertilized vegetables were over 1.1-fold better than their respective control plants. FH-AgNPs treatment enriched the total phenolic, flavonoids, and proanthocyanidin compounds in the vegetables by more than 1.05-fold. The particles positively influenced the catalase activity of the vegetables and also inhibited lipid peroxidation in precision-cut liver slices by 1.05–1.21-fold over the untreated plants. The FH-AgNPs demonstrated inhibitory activities (60.33–88.20%) against phytopathogenic Aspergillus niger, Aspergillus flavus and Fusarium solani. Application of the biogenic FH-AgNPs performed considerably better than the NPK fertilizer virtually in most cases, aside their usefulness as nanopesticides. Thus, results obtained in this study indicate that the FH-mediated AgNPs have potential application as better substitute to conventional inorganic fertilizer to promote sustainable agricultural food production in an eco-friendly manner.