Potential use of wool-associated Bacillus species for biodegradation of keratinous materials

• Published in: International biodeterioration & biodegradation Vol. 70; pp. 60 - 65
• Main Authors: Queiroga, A. Catarina, Pintado, Manuela E., Malcata, F. Xavier
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2012
• Subjects: Bacillus; Bacillus subtilis; biodegradation; chickens; culture media; enzymes; Feather; feathers; feeds; Hair; humans; Keratinase; Merino; microorganisms; Nail; Novel strains; nutritive value; Protease; proteins; ribosomal RNA; sheep; solid wastes; submerged fermentation; waste management; wool; Hair; Keratinase; Feather; Nail; Novel strains; Protease
• ISSN: 0964-8305; 1879-0208
• DOI: 10.1016/j.ibiod.2011.12.013

Five wool-degrading bacterial strains were selected from a set of 115 isolates from a less conventional source, i.e., the wool of Portuguese Merino sheep, based on their promising keratinolytic abilities. All selected strains belong to the genus Bacillus, probably Bacillus subtilis/licheniformis, according to 16S rRNA sequencing. They were able to grow on and hydrolyse feathers and wool (in both native and milled forms), and human hair and nails to a lesser extent. The maximum keratinase activity was recorded on milled chicken feathers. Biodegradation of such keratin-rich matrices increased the amount of soluble proteins in the fermentation broth and implied the action of extracellular enzymes from those adventitious microorganisms. Therefore, such novel strains have a potential for effective use in solid waste management strategies encompassing keratin-rich materials based on submerged fermentation. Concomitantly, the nutritional value of the broth may be improved for eventual formulation of animal feed. ► Five wool-degrading bacterial strains selected with notable keratinolytic activity. ► All strains able to grow and hydrolyse feathers and wool, both native and milled. ► Proteolytic stability observed over wide range of pH and temperature. ► Strains with potential for upgrading keratin-rich solid wastes.