A Statistical-Mathematical Model to Optimize Chicken Feather Waste Bioconversion via Bacillus licheniformis SHG10: A Low Cost Effective and Ecologically Safe Approach

Abstract

Feather waste is highly accumulated recalcitrant and non-efficiently utilized protein wastage of poultry processing. Present study highlights a cheap eco-friendly approach towards its valorization into efficiently utilized form (feather hydrolysate (SHG10 FH)) through Bacillus licheniformis SHG10 within 48 hrs. A statistical-mathematical model (Plackett-Burman Design (PBD), Central Composite Design (CCD), Canonical Analysis (CA) and Steepest Rising Ridge (SRR)) was anticipated to optimize feather bioconversion. PBD addressed three key determinants out of eight tested factors imposing significant influence (P≤0.006) on soluble proteins productivity. Optimal levels of the key determinants, localized by CCD, CA and SRR, were 1.55% (w/v) feather, 0.45% (w/v) yeast extract and 10.8% (v/v) inoculum size in basal medium II to attain 402 mg/Liter soluble proteins and 104,000 µmole leucine/Liter NH 2-free amino groups. SHG10 FH was rich in phenylalanine, tyrosine, methionine and histidine. MALDI-TOF-MS showed proteins spectrum of SHG10 FH ranged from 140 Da m/z. to 733 Da m/z. The composition of SHG10 FH along with the ecologically safe low cost effective approach involved in its preparation might underpin its great potential in several industries (e.g., amino acids, soluble proteins, cosmetics and animal feed livestock).

SHG10 keratinolytic alkaline protease from Bacillus licheniformis SHG10 DSM 28096: Robust stability and unusual non‐cumbersome purification

“…Pertaining to enzyme kinetics, values of K m and V max obtained on p-nitroanilides indicate enzyme preferential specificity for cutting at P1 position where aromatic or aliphatic residues exist. Present finding was previously verified by liberation of massive amounts of the aromatic amino acids (phenylalanine and tyrosine) from feathers degraded by B. licheniformis SHG10 DSM 28096 [19]. However, values of K m and V max obtained on keratin azure reflect the keratinolytic activity of SHG10 protease; an activity that was previously highlighted through feathers degradation by B. licheniformis SHG10 DSM 28096 [19].…”

“…Present finding was previously verified by liberation of massive amounts of the aromatic amino acids (phenylalanine and tyrosine) from feathers degraded by B. licheniformis SHG10 DSM 28096 [19]. However, values of K m and V max obtained on keratin azure reflect the keratinolytic activity of SHG10 protease; an activity that was previously highlighted through feathers degradation by B. licheniformis SHG10 DSM 28096 [19]. A discrepancy in the preferential site of different proteases reported in the literature for cutting could be attributed to strain differences.…”

“…Moreover, alkaline proteases with dual activities as proteases and keratinases as wide broadspectrum proteases have triggered the scientific interest during the last decades from 1990(s) till now [13][14][15][16][17][18]. The role of keratinolytic alkaline proteases in valorization of keratinous wastes particularly feather wastes, improvement of the nutritional value of feather meals, and degradation of pathogenic prion protein (PrP(Sc)) have been addressed [19][20][21][22][23]. As a consequence, searching for novel promising microbial proteases is a mandatory issue to cope with the continuous worldwide markets demand from these enzymes.…”

“…The full length of a protease encoding gene (Gb: JN85358) isolated from a new bacterial strain nominated as Bacillus licheniformis SHG10 DSM 28096 was isolated (unpublished data). The keratinolytic aspect of this enzyme was thoroughly detailed studied with regard to feathers bioconversion into beneficial end products (soluble proteins and NH 2 -free amino acids) to valorize this non-efficiently utilized waste [19]. However, purification and characterization of SHG10 keratinolytic protease enzyme have not being perceived yet.…”