Biodegradation of α and β-keratins by Gram-negative bacteria
2015
Bach, Evelise | Lopes, Fernanda Cortez | Brandelli, Adriano
The increasing amount of recalcitrant keratinous wastes generated as byproducts of agroindustrial processing has attracted attention to keratinolytic enzymes able to convert these proteins into valuable products through non-polluting processes. This work aimed to evaluate the biodegradation of α and β-keratins by three Gram-negative bacteria. All bacteria degraded feathers and feather meal and the production of keratinolytic proteases was confirmed through the azokeratin assay. An increase of thiol concentration was observed in the keratinous media cultivated with these strains, probably due to the reduction of disulfide bonds of the keratin substrate. In addition, the strains Chryseobacterium indologenes A22 and Aeromonas hydrophila K12 could also degrade hair and wool, showing a broad spectrum of keratinous wastes degradation. The influence of pH and feather meal concentration on C. indologenes A22 enzyme production was also investigated. This strain presented an optimal keratinase production on neutral pH and 15 g L−1 of substrate concentration.
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