Bacillus sp. FPF-1 Produced Keratinase with High Potential for Chicken Feather Degradation

Abstract

Chicken feathers are predominantly composed of keratin; hence, valorizing the wastes becomes an imperative. In view of this, we isolated keratinase-producing bacteria and identified them through the 16S rDNA sequence. The process condition for keratinase activity was optimized, and electron micrography of the degradation timelines was determined. Keratinolytic bacteria were isolated and identified as Bacillus sp. FPF-1, Chryseobacterium sp. FPF-8, Brevibacillus sp. Nnolim-K2, Brevibacillus sp. FPF-12 and Brevibacillus sp. FSS-1; and their respective nucleotide sequences were deposited in GenBank, with the accession numbers MG214993, MG214994, MG214995, MG214996 and MG214999. The degree of feather degradation and keratinase concentration among the isolates ranged from 62.5 ± 2.12 to 86.0 ± 1.41(%) and 214.55 ± 5.14 to 440.01 ± 20.57 (U/mL), respectively. In the same vein, 0.1% (w/v) xylose, 0.5% (w/v) chicken feather, an initial fermentation pH of 5.0, fermentation temperature of 25 °C and an agitation speed of 150 rpm, respectively, served as the optimal physicochemical conditions for keratinase activity by Bacillus sp. FPF-1. The time course showed that Bacillus sp. FPF-1 yielded a keratinase concentration of 1698.18 ± 53.99(U/mL) at 120 h. The electron microscopic imaging showed completely structural dismemberment of intact chicken feather. Bacillus sp. FPF-1 holds great potential in the valorization of recalcitrant keratinous biomass from the agro sector into useful products.

Biochemical and Molecular Characterization of a Thermostable Alkaline Metallo-Keratinase from Bacillus sp. Nnolim-K1

“…Preparation of powdered chicken feather (PCF) substrate utilized in this study followed a similar approach as we reported previously [ 19 ].…”

Microbial Keratinase: Next Generation Green Catalyst and Prospective Applications

“…The media nitrogen and carbon quotient influence microbial protease secretion and, keratinous proteins are inassimilable to microbial cells due to their structural complexity; therefore, production of elaborate keratinolytic enzymes may be regulated in response to media constituents (Riffel et al, 2011;Nnolim et al, 2020a). Worthy of note is the fact that several reports attributed unitary secreted enzymes to the complete degradation of keratin, thus controverting the position of cooperative enzyme actions.…”

“…The maintenance of homeostatic balance in extreme situations, utilization of all known material (macro and micro), and elements as sources of energy and, or cellular building tools, are attributable to the diversity of the genome and the complexity of the microbial expression systems (Francino, 2012). Keratinases, are inducible enzymes that allow the producer microbe to utilize the keratinous biomass as a nutrient source (Gupta and Ramnani, 2006;Nnolim et al, 2020a), and the process occurs only in the presence of keratinous biomass and the absence of readily available nutritional reference; hence, keratinase production only kick-starts out of necessity. The exudation of keratinase offers microbes the opportunity to utilize a broad spectrum of proteinaceous substrates, thus promoting organic matter recycling in all ecological milieu (Bohacz and Korniłłowicz-Kowalska, 2019).…”

“…Conventionally processed protein-rich feeds of keratin origin are not typically metabolized by animals due to the absence of the redox system that hydrolyses the disulfide bonds of the polypeptides (Wang et al, 2006;Lange et al, 2016). Hence, the nutritive value of keratin-based feed-products needs to be improved by enhancing protein digestibility and nutrient availability (Nnolim et al, 2020a). Keratinase-mediated keratin solubilization offers a solution toward improving the nutritional qualities of the keratin-based feed-products in the fermentative process, which may be submerged or solid state (Łaba and Szczekała, 2013).…”

Microbial keratinase and the bio-economy: a three-decade meta-analysis of research exploit

“…Thus, the imperative for a reliable alternative motivates for the exploration of highly abundant renewable resources for sustainable products. The potentials locked in carbonoclastic materials account for the desire to valorize waste biomass into high-value products, and that ensures sustainability in economic development (Akinsemolu 2018 ; Nnolim et al 2020a ). The agro and food industry generates lots of solid wastes which may suitably feed into the economy with novel valorization approach.…”