Ameliorating effects of chicken feathers in plant growth promotion activity by a keratinolytic strain of Bacillus subtilis PF1

Abstract

Background: Feathers are the major byproducts of poultry industry and considered as waste. Feathers (composed of protein keratin) are metabolized by a number of microorganisms as a source of carbon and nitrogen. Degradation of feathers results in production of amino acids and peptides, which can be employed as precursors for plant growthpromoting metabolites such as indole acetic acid, ammonia and HCN. The aim of the present investigation was to assess the influence of these metabolites (termed as feather protein hydrolysate) on plant growth promotion activity of keratinolytic bacterial strain Bacillus subtilis PF1.Results: Strain PF1 exhibits potent keratinolytic activity and can efficiently degrade 10 g/l chicken feathers under submerged cultivation with 81.4 ± 4.40 U/ml keratinase activity. Different concentrations of feathers supported the production of indole acetic acid by strain PF1. Strain PF1 produces maximum indole acetic acid (46.2 ± 0.21 µg/ml) in the presence of 2.0 % feathers at 120 h of incubation. The indole acetic acid production was confirmed by thin-layer chromatography and Fourier transform infrared spectroscopic analysis. However, increased concentration of feathers exhibited negative effect on phosphate solubilization due to increased alkalinity. HCN production also exhibited positive correlation with concentration of feathers. Finally, plant growth of Vigna radiata in the presence of strain PF1 with chicken feathers in soil was investigated, which showed good plant growth promotion activity. Increased ratio of C/N in soil also supported the plant growth promotion activity of feathers. Conclusion:Feather degradation property of B. subtilis PF1 could be efficiently utilized for feather waste management. The metabolites released by feather degradation along with strain PF1 could be successfully employed as an economic source of nitrogen fertilizers for plants.

Synergistic effect of Chryseobacterium gleum sp. SUK with ACC deaminase activity in alleviation of salt stress and plant growth promotion in Triticum aestivum L.

“…SUK as per the biochemical properties and 16S rDNA gene sequences. There are few reports on the role of degraded feather lysate to promote plant growth as they are rich source of nitrogen (Bhange et al 2016;Kim et al 2001). Although the Chryseobacterium genus is known to have strong keratinase activity (Riffel et al 2007;Wang et al 2008); however, this is the first report on salinity stress amelioration using the combination of ACC deaminase producing organism with feather-degraded lysate.…”

“…Studies have reported that the plant growth promoting bacterial inoculation to the crops increases the fresh and dry weight of the root system (Yuan et al 2013). Similarly, Bhange et al (2016) reported an increase in root length and root and shoot weight of Vigna radiata L. due to the addition of feather-degraded lysate with the degrading isolate Bacillus subtilis PF1. Results showed the effects of both the inoculum on the vegetative parameters which indicate that the ACC deaminase activity of isolate reduces the salinity stress while the biostimulants present in bioformulation significantly improved the growth of plant.…”

Feather degradation by keratinolytic bacteria and biofertilizing potential for sustainable agricultural production

“…Feather degradation by keratinolytic strains Bacillus licheniformis increases the pH of the medium . Similarly, a slight increase in pH was observed in soil amended with keratinolytic strain Bacillus subtilis and degraded feather metabolite . …”

Characterization and overexpression of a novel keratinase from Bacillus polyfermenticus B4 in recombinant Bacillus subtilis

“…Many attempts have been made to convert keratinous waste to smaller debris or protein hydrolysates through physical and chemical treatments (Gupta et al 2013), which can then be used as nutrient additives in animal feed, agriculture, and cosmetic industries (Bhange et al 2016). However, the conventional treatment methods could deteriorate the quality and stability of the hydrolyzed products, adding to environmental concerns such as strong acidification or alkalinization of water through the generated waste.…”

“…Keratinases have been reported in many microorganisms such as bacteria, actinomycetes, and fungi (Bhange et al 2016). Moreover, KerA, isolated from Bacillus licheniformis PWD-1, is the most well-characterized keratinase (Lin et al 1995;Onifade et al 1998).…”