[Influence of culture medium on the viability and membrane fatty acid composition of Oenococcus oeni SD-2a].
OBJECTIVE
To achieve the high quality of malo-lactic starter cultures, we investigated the effect of three culture media on the direct inoculation viability, freeze-drying viability and membrane fatty acid composition of Oenococcus Oeni SD-2a.


METHODS
We monitored the bacterial growth and change in medium pH when O. oeni SD-2a cells were cultured in ATB, FMATB and MATB media. O. oeni SD-2a cells in early stationary phase were harvested, and subjected to direct inoculation experiments and freeze-drying processes. Then we determined inoculation and freeze-drying viability. Membrane fatty acid composition of those corresponding O. oeni SD-2a cells was determined by GC/MS method.


RESULTS
The results showed ATB medium without supplementation of DL-malate had weak pH buffering capability. Compared with FMATB and MATB, O. oeni cells cultured in ATB increased inoculation viability and freeze-drying viability. Concerning the membrane fatty acid composition, it was observed that ATB medium increased distinctly the relative concentration of lactobacillic acid (C19cyc11) and U/S (the unsaturated: saturated fatty acid) ratio in cell membrane lipid composition of O. oeni SD-2a.


CONCLUSIONS
The increased resistance to wine stressor and freeze-drying was probably a result of the cross protection conferred by self acid stress response induced in ATB medium, which might be related with changes in membrane fatty acid composition of O.oeniSD-2a. Therefore, ATB medium was more suitable for preparation of O. oeni SD-2a commercial starter cultures.
Zhao
Wenying
W
College of Enology, Northwest University of Agriculture and Forestry, Yangling 712100, China. zzr1zwy2@sohu.com
Li
Hua
H
Wang
Ailian
A
Li
Zhongchao
Z
Wang
Hua
H
D003470:Culture Media / Q000737:chemistry / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry* / Q000378:metabolism; D006094:Gram-Positive Bacteria / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008563:Membrane Lipids / Q000737:chemistry* / Q000378:metabolism; D050296:Microbial Viability
D003470:Culture Media; D005227:Fatty Acids; D008563:Membrane Lipids