Mycobiology.  2003 Dec;31(4):209-213.

Preliminary Characterization of Keratinolytic Enzyme of Aspergillus flavus K-03 and Its Potential in Biodegradation of Keratin Wastes

• Kim JD

Abstract

Aspergillus flavus K-03 isolated from poultry forming soil in Korea was studied for its ability to produce extracellular proteases on basal medium containing 2% (w/v) chicken feathers. The fungus was observed to be a potent producer of such enzymes. Keratinolytic enzyme secretion was the best at 15 days of incubation period at pH 9 and temperature 40degrees C. No relationship existed between the enzyme yield and increase of biomass. Enzyme production was suppressed by exogenous sugars in descending order arabinose>maltose>mannose>fructose. But glucose did not influence the enzyme activity. The keratinolytic enzyme released by the fungus demonstrated the ability to decompose keratin substrates as chicken feather when exogenous glucose was present. The keratinolytic activity was inhibited by HgCl2 and serine-protease inhibitors such as phenymethylsulfonyl fluoride (100%), chymostain (88%), crystalline soybean trypsin inhibtor (80%), antipain (45%) and aprotinin (40%), and was not by cystein-protease and aspartyl-protease inhibitors. The enzyme activity is only partially inhibited by metallo-protease inhibitor. Thus, the enzyme secreted by A. flavus K-03 belongs to the alkaline serine-type protease.

Keyword

Alkaline serine-type keratinolytic protease; Aspergillus flavus; Extracellular enzyme; Keratinolytic enzyme

MeSH Terms

Animals
Antipain
Aprotinin
Aspergillus flavus*
Aspergillus*
Biomass
Carbohydrates
Chickens
Crystallins
Feathers
Fluorides
Fungi
Glucose
Hydrogen-Ion Concentration
Korea
Mercuric Chloride
Peptide Hydrolases
Poultry
Soil
Soybeans
Trypsin
Antipain
Aprotinin
Carbohydrates
Crystallins
Fluorides
Glucose
Mercuric Chloride
Peptide Hydrolases
Soil
Trypsin