Optimization for production of liquid nitrogen fertilizer from the degradation of chicken feather by iron-oxide (Fe3O4) magnetic nanoparticles coupled β-keratinase

Abstract

There is an escalating demand for balancing crop yields with a reduction in the environmental impacts caused by synthetic fertilizers, and focusing on sustainable agricultural practice using organic fertilizers high in nitrogen and increased soil water retention capability. The current study demonstrates a significantly improved chicken-feather hydrolyzate prepared by Bacillus licheniformis AS-S24-I β-keratinase coupled iron-oxide magnetic nanoparticles. Biochemical and proteomic characterization suggests alkarnase as a serine protease in nature with broad pH stability as well as incubation temperature. The Scanning Electron Microscope (SEM) study reveals that iron-oxide (Fe3O4) magnetic nanoparticles coupled β-keratinase can degrade 80–93% of chicken-feather keratin post 48 h of incubation. Chicken-feather hydrolyzate demonstrated the release of six volatile compounds post treated with iron-oxide (Fe3O4) magnetic nanoparticles coupled β-keratinase via Gas Chromatography–Mass Spectrophotometry (GC–MS) and matrix-assisted laser desorption/ionization-time-of-flight MS (MALDI–TOF–MS) analyzes, respectively. The release of low volatile compounds post degradation recommended that it could be a sustainable method of eco-friendly organic fertilization. The results of the physiochemical analysis suggested improved nitrogen and amino acid levels indicating that chicken-feather hydrolyzate was a good organic fertilizer source. Filtered sterilized chicken-feather hydrolyzate revealed a significant increase in the length and growth of Bengal gram seed germination, as well a rise in the soil microbial population. Thus, the present study offers significant biotechnological applications of chicken-feather hydrolyzate, which could serve as a cheap source of liquid organic fertilizer.