Study of the Production of Alkaline Keratinases in Submerged Cultures as an Alternative for Solid Waste Treatment Generated in Leather Technology

• Published in: Journal of microbiology and biotechnology Vol. 23; no. 7; pp. 1004 - 1014
• Main Authors: Cavello, I.A., Research and Development Center for Industrial Fermentations, Argenitina, Chesini, M., Research and Development Center for Industrial Fermentations, Argenitina, Hours, R.A., Research and Development Center for Industrial Fermentations, Argenitina, Cavalitto, S.F., Research and Development Center for Industrial Fermentations, Argenitina
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society for Applied Microbiology 01.07.2013; 한국미생물·생명공학회
• Subjects: Argentina; Biological and medical sciences; Biological treatment of sewage sludges and wastes; Biotechnology; Biotechnology - methods; Biotransformation; Culture Media - chemistry; DECHET SOLIDE; DESECHOS SOLIDOS; Environment and pollution; Fundamental and applied biological sciences. Psychology; Fungi - classification; Fungi - enzymology; Fungi - isolation & purification; Fungi - metabolism; Hydrogen-Ion Concentration; Industrial applications and implications. Economical aspects; Industrial Microbiology - methods; Industrial Waste; Keratinases,hair waste,leather technology,Purpureocillium lilacinum; Medical Waste Disposal - methods; Metals - metabolism; Peptide Hydrolases - metabolism; Soil Microbiology; Solid Waste; SOLID WASTES; Temperature; 생물학; Argentina; Keratinases; Submerged culture; Technology; Waste treatment; leather technology; Production; hair waste; Solid waste; Leather; Purpureocillium lilacinum
• ISSN: 1017-7825; 1738-8872
• DOI: 10.4014/jmb.1211.11016

Six nonpathogenic fungal strains isolated from alkaline soils of Buenos Aires Province, Argentina (Acremonium murorum, Aspergillus sidowii, Cladosporium cladosporoides, Neurospora tetrasperma, Purpureocillium lilacinum (formerly Paecilomyces lilacinus), and Westerdikella dispersa) were tested for their ability to produce keratinolytic enzymes. Strains were grown on feather meal agar as well as in solid-state and submerged cultures, using a basal mineral medium and “hair waste” as sole sources of carbon and nitrogen. All the tested fungi grew on feather meal agar, but only three of them were capable of hydrolyzing keratin, producing clear zones. Among these strains, P. lilacinum produced the highest proteolytic and keratinolytic activities, both in solid-state and submerged fermentations. The medium composition and culture conditions for the keratinases production by P. lilacinum were optimized. Addition of glucose (5 g/l) and yeast extract (2.23 g/l) to the basal hair medium increased keratinases production. The optimum temperature and initial pH for the enzyme production were 28oC and 6.0, respectively. A beneficial effect was observed when the original concentration of four metal ions, present in the basal mineral medium, was reduced up to 1:10. The maximum yield of the enzyme was 15.96 Uc/ml in the optimal hair medium; this value was about 6.5-fold higher than the yield in the basal hair medium. These results suggest that keratinases from P. lilacinum can be useful for biotechnological purposes such as biodegradation (or bioconversion) of hair waste, leading to a reduction of the environmental pollution caused by leather technology with the concomitant production of proteolytic enzymes and protein hydrolyzates.