Optimal culture conditions for keratinase production by a novel thermophilic Myceliophthora thermophila strain GZUIFR-H49-1.
OBJECTIVE
To investigate the effect of medium compositions and culture conditions on keratinase production by a novel thermophilic fungus Myceliophthora thermophila (Apinis) Oorschot strain GZUIFR-H49-1.


RESULTS
The thermophilic strain GZUIFR-H49-1 with keratinolytic ability was characterized and identified as a strain of M. thermophila on the basis of its morphological characters and molecular analysis of ITS1-5.8S-ITS2 rDNA sequence. Among the medium compositions tested, the soluble starch (SS), urea, sodium thiosulfate and CaCl2 were the most effective C-source, N-source, S-source and mineral ion, respectively, by employing the single-factor experiment. The urea and pH value were the significant factors (P < 0·05) for the keratinase production in this experiment condition using Plackett–Burman factorial design. The conditions of keratinase production were further optimized by Box–Behnken design. Consequently, there was a 6·4-fold increase (5100 U l−1) in the keratinase activity than the initial value (800 U l−1) by this optimal process.


CONCLUSIONS
This study indicated that the optimization design proved a useful and powerful tool for the development of optimal medium compositions and culture conditions. Myceliophthora thermophila strain GZUIFR-H49-1 was a promising fungus strain for keratinase production.
Institute of Fungus Resources, Guizhou University, Guiyang, China.
J D
JD
Liang
Y F
YF
Han
J W
JW
Zhang
W
W
Du
Z Q
ZQ
Liang
Z Z
ZZ
Li
D003470:Culture Media; D003627:Data Interpretation, Statistical; D005285:Fermentation; D010447:Peptide Hydrolases / Q000096:biosynthesis*; D020037:Sordariales / Q000145:classification / Q000166:cytology / Q000201:enzymology* / Q000302:isolation & purification
D003470:Culture Media; D010447:Peptide Hydrolases; C035855:keratinase