Zhang Guiying, Mills David A, Block David E
Department of Food Science and Technology, University of California, One Shields Avenue, Davis, CA 95616, USA.
Appl Environ Microbiol. 2009 Feb;75(4):1080-7. doi: 10.1128/AEM.01416-08. Epub 2008 Dec 12.
Lactococcus lactis IL1403 was used as an experimental strain to develop a chemically defined medium for study of the physiology and metabolic pathways of lactococci. An experimental leave-one-out technique was employed to determine the necessity of each of the 57 chemical components used in medium development. A statistical experimental design approach including three fractional factorial designs and a central composite design was used to optimize the fermentation process with 21 variables composed of 19 nutritional factors grouped from the 57 components and two environmental factors (initial pH and temperature). For L. lactis IL1403, the maximum biomass concentrations obtained with the two optimal chemically defined media developed in this study (ZMB1 and ZMB2) were generally 3.5- to 4-fold higher than the maximum biomass concentrations obtained with the previously described best synthetic media (SA) and 50% to 68% higher than the maximum biomass concentrations obtained with M17, a complex medium commonly used for lactococci. The new chemically defined media support high-cell-density growth of numerous strains of L. lactis, Enterococcus faecalis, and Streptococcus thermophilus.
乳酸乳球菌IL1403被用作实验菌株，以开发一种化学成分明确的培养基，用于研究乳球菌的生理学和代谢途径。采用实验性留一法来确定培养基开发中使用的57种化学成分中每种成分的必要性。一种包括三个部分因子设计和一个中心复合设计的统计实验设计方法被用于优化发酵过程，该过程有21个变量，由从57种成分中分组得到的19种营养因子和两个环境因子（初始pH值和温度）组成。对于乳酸乳球菌IL1403，本研究开发的两种最佳化学成分明确的培养基（ZMB1和ZMB2）所获得的最大生物量浓度，通常比先前描述的最佳合成培养基（SA）所获得的最大生物量浓度高3.5至4倍，比常用于乳球菌的复合培养基M17所获得的最大生物量浓度高50%至68%。新的化学成分明确的培养基支持多种乳酸乳球菌、粪肠球菌和嗜热链球菌菌株的高细胞密度生长。
