RESUMO
The aim of the study was to characterize feather-degrading bacteria isolated from poultry industry waste. A Vibrio sp. strain kr2 producing a high keratinolytic activity when cultured on native feather-containing broth was isolated. The bacterium grew with an optimum at pH 6.0 and 30 degrees C, where maximum featherdegrading activity was also observed. Keratinase production was similar at both 25 and 30 degrees C, while the maximum concentration of soluble protein was reached at 30 degrees C. Reduction of disulphide bridges was also observed, increasing with cultivation time. The keratinase of strain kr2 was active on azokeratin, azocasein, benzoyl-arginine-p-nitroanilide and Ala-Ala-p-nitroanilide as substrates. The amino acid composition of the feather hydrolysate was determined, presenting similarities with that reported for feather lysate, feather meal and raw feathers. A novel feather-degrading bacterium was isolated and characterized, showing high keratinolytic activity. Complete feather degradation was achieved during cultivation. Strain kr2 shows potential for use for biotechnological processes involving keratin hydrolysis.
Assuntos
Plumas/microbiologia , Queratinas/química , Vibrio/enzimologia , Aminoácidos/análise , Animais , Benzoilarginina Nitroanilida/química , Caseínas/química , Plumas/química , Concentração de Íons de Hidrogênio , Hidrólise , Resíduos Industriais , Oxirredutases/química , Oxirredutases atuantes sobre Doadores de Grupo Enxofre , Peptídeo Hidrolases/química , Aves Domésticas/microbiologia , Temperatura , Vibrio/isolamento & purificaçãoRESUMO
Feather waste, generated in large quantities as a byproduct of commercial poultry processing, is almost pure keratin, which is not easily degradable by common proteolytic enzymes. Feather-degrading bacteria were isolated from a Brazilian poultry industrial waste. Among these isolates, a strain identified as kr2 was the best feather-degrading organism when grown on basal medium containing 10 g/L of native feather as a source of energy, carbon, and nitrogen. The isolate was characterized according to morphological characteristics and biochemical tests belonging to the Vibrionaceae family. Keratinolytic activity of this isolate was monitored throughout the cultivation of the bacterium on raw feather at different temperatures. The optimum temperature for growth was about 30 degrees C, at which maximum enzyme and soluble protein production were achieved. The enzyme had a pH and temperature optima of 8.0 and 55 degrees C, respectively.
