title: Response surface methodology for optimizing the fermentation medium of alpha-galactosidase in solid-state fermentation.
abstract: OBJECTIVE
  Alpha-galactosidase is applied in food and feed industries for hydrolysing raffinose series oligosaccharides (RO) that are the factors primarily responsible for flatulence upon ingestion of soybean-derived products. The objective of the current work was to develop an optimal culture medium for the production of alpha-galactosidase in solid-state fermentation (SSF) by a mutant strain Aspergillus foetidus.
  
  
  RESULTS
  Response surface methodology (RSM) was applied to evaluate the effects of variables, namely the concentrations of wheat bran, soybean meal, KH(2)PO(4), MnSO(4).H(2)O and CuSO(4).5H(2)O on alpha-galactosidase production in the solid substrate. A fractional factorial design (FFD) was firstly used to isolate the main factors that affected the production of alpha-galactosidase and the central composite experimental design (CCD) was then adopted to derive a statistical model for optimizing the composition of the fermentation medium. The experimental results showed that the optimum fermentation medium for alpha-galactosidase production by Aspergillus foetidus ZU-G1 was composed of 8.2137 g wheat bran, 1.7843 g soybean meal, 0.001 g MnSO(4).H(2)O and 0.001 g CuSO(4).5H(2)O in 10 g dry matter fermentation medium.
  
  
  CONCLUSIONS
  After incubating 96 h in the optimum fermentation medium, alpha-galactosidase activity was predicted to be 2210.76 U g(-1) dry matter in 250 ml shake flask. In the present study, alpha-galactosidase activity reached 2207.19 U g(-1) dry matter.
  
  
  CONCLUSIONS
  Optimization of the solid substrate was a very important measure to increase enzyme activity and realize industrial production of alpha-galactosidase. The process of alpha-galactosidase production in laboratory scale may have the potential to scale-up.
authors.affiliation: Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310029, China.
authors.forename: C Q
authors.initials: CQ
authors.lastname: Liu
authors.forename: Q H
authors.initials: QH
authors.lastname: Chen
authors.forename: B
authors.initials: B
authors.lastname: Tang
authors.forename: H
authors.initials: H
authors.lastname: Ruan
authors.forename: G Q
authors.initials: GQ
authors.lastname: He
mesh_terms: D001230:Aspergillus / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D004043:Dietary Fiber / Q000378:metabolism; D005285:Fermentation; D007218:Industrial Microbiology / Q000379:methods; D008954:Models, Biological; D009584:Nitrogen / Q000378:metabolism; D000519:alpha-Galactosidase / Q000096:biosynthesis* / Q000302:isolation & purification
chemical_list: D003470:Culture Media; D004043:Dietary Fiber; D002244:Carbon; D000519:alpha-Galactosidase; D009584:Nitrogen