title: Use of response surface methodology for optimizing process parameters for high inulinase production by the marine yeast Cryptococcus aureus G7a in solid-state fermentation and hydrolysis of inulin.
abstract: The optimization of process parameters for high inulinase production by the marine yeast strain Cryptococcus aureus G7a in solid-state fermentation (SSF) was carried out using central composite design (CCD), one of the response surface methodologies (RSMs). We found that moisture, inoculation size, the amount ratio of wheat bran to rice husk, temperature and pH had great influence on inulinase production by strain G7a. Therefore, the CCD was used to evaluate the influence of the five factors on the inulinase production by strain G7a. Then, five levels of the five factors above were further optimized using the CCD. Finally, the optimal parameters obtained with the RSM were the initial moisture 61.5%, inoculum 2.75%, the amount ratio of wheat bran to rice husk 0.42, temperature 29 degrees C, pH 5.5. Under the optimized conditions, 420.9 U g(-1) of dry substrate of inulinase activity was reached in the solid-state fermentation culture of strain G7a within 120 h whereas the predicted maximum inulinase activity of 436.2 U g(-1) of inulinase activity of 436.2 U g(-1) of dry weight was derived from the RSM regression. This is the highest inulinase activity produced by the yeast strain reported so far. A large amount of monosaccharides and oligosaccharides were detected after inulin hydrolysis by the crude inulinase.
authors: UNESCO Chinese Center of Marine Biotechnology, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
authors: Jun
authors: J
authors: Sheng
authors: Zhenming
authors: Z
authors: Chi
authors: Kuirang
authors: K
authors: Yan
authors: Xianghong
authors: X
authors: Wang
authors: Fang
authors: F
authors: Gong
authors: Jing
authors: J
authors: Li
mesh_terms: D000465:Algorithms; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D003198:Computer Simulation; D003454:Cryptococcus / Q000145:classification / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006868:Hydrolysis; D007444:Inulin / Q000378:metabolism*; D008386:Marine Biology; D008954:Models, Biological; D011786:Quality Control; D013045:Species Specificity
chemical_list: D007444:Inulin; D006026:Glycoside Hydrolases; C023086:inulinase