title: Optimization of a cultural medium for bacteriocin production by Lactococcus lactis using response surface methodology.
abstract: The medium composition for bacteriocin production by Lactococcus lactis ATCC 11454 was optimized using response surface methodology. The selected six factors based on CM medium were sucrose, soybean peptone, yeast extract, KH(2)PO(4), NaCl, and MgSO(4).7H(2)O. Fractional factorial designs (FFD) and the path of steepest ascent were effective in searching for the main factors and approaching the optimum region of the response. By a 2(6-2) FFD, sucrose, soybean peptone, yeast extract, KH(2)PO(4) were found to be significant factors and had positive effects on cell growth, however, only soybean peptone and KH(2)PO(4) were shown to be the two significant factors for bacteriocin production and had negative and positive effects, respectively. The effects of the two main factors on bacteriocin production were further investigated by a central composite design and the optimum composition was found to be 1% sucrose, 0.45% soybean peptone, 1% yeast extract, 2.84% KH(2)PO(4), 0.2% NaCl, and 0.02% MgSO(4) x 7H(2)O. The optimal medium allowed bacteriocin yield to be doubled compared to CM medium.
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Chemical Metallurgy, Chinese Academy of Sciences, P.O. Box 353, Beijing 100080, People's Republic of China. chanlixyl@hotmail.com
authors.forename: Chan
authors.initials: C
authors.lastname: Li
authors.forename: Jinghua
authors.initials: J
authors.lastname: Bai
authors.forename: Zhaoling
authors.initials: Z
authors.lastname: Cai
authors.forename: Fan
authors.initials: F
authors.lastname: Ouyang
mesh_terms: D001430:Bacteriocins / Q000096:biosynthesis*; D001709:Biotechnology; D002455:Cell Division; D003470:Culture Media / Q000737:chemistry*; D013294:Lactococcus lactis / Q000254:growth & development / Q000378:metabolism*; D017616:Magnesium Compounds; D008954:Models, Biological; D009561:Nisin / Q000096:biosynthesis; D009584:Nitrogen; D010461:Peptones; D010710:Phosphates; D017680:Potassium Compounds; D012965:Sodium Chloride; D013395:Sucrose
chemical_list: D001430:Bacteriocins; D003470:Culture Media; D017616:Magnesium Compounds; D010461:Peptones; D010710:Phosphates; D017680:Potassium Compounds; D009561:Nisin; D012965:Sodium Chloride; C030781:magnesium phosphate; D013395:Sucrose; C013216:potassium phosphate; D009584:Nitrogen