菌种储藏温度及菌种活化对头孢霉脂肪酸组分的影响

为了获得高含量的二十二碳六烯酸(DHA)，对不同储藏温度对头孢霉脂肪酸组分的影响进行研究。将菌种储藏在20℃。4℃和-20℃三种温度下。比较不同储藏时间及菌种活化对菌丝脂肪酸组分的影响。结果表明菌种储藏温度、时间及发酵前菌种是否活化都影响脂肪酸组分。发酵前活化菌种。DHA含量均在10d达到最大：不活化菌种。20℃储藏菌种，DHA在20d可以达到最大：4℃，在25d可以达到最大：-20℃，在5d可以达到最大。除4℃外，其它两种温度下多不饱和脂肪酸变化和DHA变化趋势均一致。20℃，脂肪酸不饱和指数和18：3，18：2的变化与DHA变化一致。-20℃储藏菌种。如发酵前不活化菌种，其DHA，脂肪酸不饱和指数和多不饱和脂肪酸变化幅度均为六组最小。可能在这种温度下，菌丝调节脂肪酸变化的能力受到损伤。本研究可以为发酵生产多不饱和脂肪酸提供理论参考。

Effect of Strain Storing and Reculturing Conditions on The Cephalosporium sp.Mycelium's Fatty Acid Composition

To get high content of docosahexaenoic acid (DHA, ω-3), the effects on the Cephalosporium sp. mycelium' s fatty acid composition of strain storing and culturing conditions were studied. The strgins containing microorangism were stored at 20℃、4℃and-20℃ for different times respectively. The fatty acids were analyzed by GC. The results showed that the fatty acid composition was affected by the storing temperature、storing time no matter how the strain was activated on new agar before fermentation. Ifthe strain was cultured on new agar before fermentation, the 10d period was the best storing time to get highDHA content. Ifnot cultured, to the 20℃, the best time was 20d; to the 4℃, the best time was 25d and to -20℃, it was 5d. The polyunsaturated fatty acid (PUFA) changed the same tendency as the DHA' s but at 4℃ not so. At 20℃, the index of unsaturated fatty acid (IUFA) and the 18:3 ( α -)/18:2 changed with the same tendency as the DHA's. Storing the strain at -20℃. the PUFA、IUFA and DHA fluctuated at the lowest range. This study could give a theoretical reference for producing high yield of DHA by microorganisms.