Fusarium oxysporum and Aspergillus sp. as Keratinase Producers Using Swine Hair From Agroindustrial Residues.

Karina Paula Preczeski,Charline Bonatto,Fabiane Fernanda Czapela,Caroline Dalastra,Gislaine Fongaro,Bruno Venturin,Simone Kubeneck,Aline Frumi Camargo,Fábio Spitza Stefanski,Jessica Zanivan,Helen Treichel,Thamarys Scapini

doi:10.3389/fbioe.2020.00071

Abstract

Technological processes mediated by microorganisms and enzymes are promising alternatives for treatment of recalcitrant residues. Keratinases hydrolyze keratin, the primary component of some wastes generated in many industrial activities. The present study was designed to evaluate strategies for obtaining keratinases produced by fungi using submerged fermentation and two residues as substrates, chicken feathers and swine hair. Two fungi isolated from feather residues showed potential for keratinase production, Fusarium oxysporum and Aspergillus sp. These were subjected to submerged fermentation using chicken feathers and swine hair prepared in three conditions (microbial concentration reduction, sterilization and hydrogen peroxide). The residual mass was quantified and tested for keratinase production. The most potent enzymatic extract was used in the precipitation technique with salts and organic solvents. The best results of enzymatic activity were obtained using F. oxysporum, on the 6thday of fermentation, obtaining 243.25 U mL–1 using sterilized swine hair as the substrate. Aspergillus sp. showed the highest keratinolytic activity on the 9thday, 113.50 U mL–1 using feathers as the substrate. The highest degradation percentage was 59.20% (w/w) in swine hair and the precipitation technique, with relative activities close to 50%. The results are promising for the application of residues and microorganisms in biotechnological processes of economic and environmental interest.

Highlights

Brazil holds a prominent position in the meat production sector, generating enormous volumes of agroindustrial residues that consist primarily of keratin; these include chicken feathers and swine hair (Pond et al, 1991; Onifade et al, 1998; BAAP, 2018; Freitas et al, 2018)
We evaluated strategies for obtaining keratinases produced by fungi using submerged fermentation and two residues as a source of keratin, chicken feathers and swine hair
Four morphologically distinct microorganisms were isolated from chicken feathers

Summary

Introduction

Brazil holds a prominent position in the meat production sector, generating enormous volumes of agroindustrial residues that consist primarily of keratin; these include chicken feathers and swine hair (Pond et al, 1991; Onifade et al, 1998; BAAP, 2018; Freitas et al, 2018). GRAPHICAL ABSTRACT | Schematic diagram of keratinases production using swine hair from agroindustrial residues. An alternative that would harness the values of these residues would be to use them to obtain fungi. In this scenario, it is possible to produce proteins with substantial commercial value and at the same time pre-treat the residue with microorganisms (Łaba et al, 2015). The remaining residue can be sent for composting (Choinska-Pulit et al, 2019) or some other fermentation process

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Conclusion