知识与财富的链接
[目的] 为获得高效的葡萄酒乳酸菌发酵剂,本文研究了3种具有不同pH缓冲能力的培养基对酒酒球菌接种存活率、冻干存活率及细胞膜脂肪酸组分的影响.[方法]采用平板计数法测定菌体的接种存活率、冻干存活率;并采用GC/MS色谱方法测定收获菌体细胞膜脂肪酸组分.[结果]实验结果表明,没有添加苹果酸的ATB培养基,其pH缓冲能力弱.分别与FMATB和MATB培养基相比,ATB培养基培养获得的菌体,其接种模拟酒培养基后的存活率提高了20.3%和40.2%,其冷冻干燥存活率提高了48.5%和68.3%,其细胞膜中C19cyc11的相对含量提高了10.0%和36.8%,其细胞膜U/S值提高了20.4%和45.2%.[结论]本文推测ATB培养基培养所得菌体,由于自我酸胁迫反应,增强了其对葡萄酒胁迫因素及冷冻干燥的抗性,而该反应与菌体细胞膜脂肪酸组分的变化密切相关.故ATB培养基更适合于酒酒球菌SD-2a发酵剂的制备.
[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 sup-plementation 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. [Conclusion] 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.
