title: Optimization of medium constituents for ε-poly-L-lysine fermentation with response surface methodology.
abstract: ε-Poly-L-lysine (ε-PL) is a novel food biopreservative with broad antimicrobial activity. In the present study, single-factor experiments were applied to screen optimal carbon and nitrogen sources that affect the yield of a ε-PL-producing strain, Streptomyces violaceusniger, which was obtained in our laboratory recently. Box-Behnken design and response surface methodology (RSM) were adopted to derive a statistical model for optimizing the composition of the fermentation medium. The results showed that the main factors that affect ɛ-PL production were glucose, carbon source; peptone, organic nitrogen source; and (NH(4))(2)SO(4), inorganic nitrogen source. The optimum fermentation medium for ɛ-PL production of S. violaceusniger consisted of (g/L) glucose, 62.49; peptone, 5.71; (NH(4))(2)SO(4), 11.19; MgSO(4), 0.5; FeSO(4), 0.03; ZnSO(4), 0.04; KH(2)PO(4), 1.36; and Na(2)HPO(4).12H(2)O, 3.58. When cultured in the optimum medium, the ε-PL production was an average of 0.349 ± 0.025 mg/mL, which was 1.75 times higher than the initial medium.
authors.affiliation: Dept. of Food Science and Nutrition, Huajiachi Campus, Zhejiang Univ., Hangzhou, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zong
authors.forename: Yibo
authors.initials: Y
authors.lastname: He
authors.forename: Yao
authors.initials: Y
authors.lastname: Zhan
authors.forename: Juan
authors.initials: J
authors.lastname: Du
authors.forename: Fengqin
authors.initials: F
authors.lastname: Feng
authors.forename: Duo
authors.initials: D
authors.lastname: Li
mesh_terms: D003470:Culture Media; D005285:Fermentation; D007218:Industrial Microbiology; D009584:Nitrogen / Q000378:metabolism; D011107:Polylysine / Q000096:biosynthesis*; D013302:Streptomyces / Q000378:metabolism
chemical_list: D003470:Culture Media; D011107:Polylysine; D009584:Nitrogen