Statistical optimization of alkaline protease production from Penicillium citrinum YL-1 under solid-state fermentation.
Proteases from halotolerant and halophilic microorganisms were found in traditional Chinese fish sauce. In this study, 30 fungi were isolated from fermented fish sauce in five growth media based on their morphology. However, only one strain, YL-1, which was identified as Penicillium citrinum by internal transcribed spacer (ITS) sequence analysis, can produce alkaline protease. This study is the first to report that a protease-producing fungus strain was isolated and identified in traditional Chinese fish sauce. Furthermore, the culture conditions of alkaline protease production by P. citrinum YL-1 in solid-state fermentation were optimized by response surface methodology. First, three variables including peptone, initial pH, and moisture content were selected by Plackett-Burman design as the significant variables for alkaline protease production. The Box-Behnken design was then adopted to further investigate the interaction effects between the three variables on alkaline protease production and determine the optimal values of the variables. The maximal production (94.30 U/mL) of alkaline protease by P. citrinum YL-1 took place under the optimal conditions of peptone, initial pH, and moisture content (v/w) of 35.5 g/L, 7.73, and 136%, respectively.
a College of Food Science , South China Agricultural University , Guangzhou , P.R. China.
Yun-Zhu
YZ
Xiao
Duan-Kai
DK
Wu
Si-Yang
SY
Zhao
Wei-Min
WM
Lin
Xiang-Yang
XY
Gao
D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis*; D002244:Carbon / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D010450:Endopeptidases / Q000096:biosynthesis*; D005285:Fermentation; D005399:Fishes / Q000382:microbiology; D005516:Food Microbiology / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008432:Mathematical Computing; D009584:Nitrogen / Q000378:metabolism; D010407:Penicillium / Q000302:isolation & purification* / Q000378:metabolism*; D010461:Peptones / Q000378:metabolism
D001426:Bacterial Proteins; D003470:Culture Media; D010461:Peptones; D002244:Carbon; D010450:Endopeptidases; C087822:alkaline protease; D009584:Nitrogen
Penicillium citrinum; Plackett-Burman design; alkaline protease; optimization; response surface methodology