寇氏隐甲藻(crypthecodinium+cohnii)培养生产dha地研究.pdf

摘要

DHA(二十二碳六烯酸)在婴幼儿大脑发育和视力发育中具有非常重要的生理
作用,并且具有防治心血管疾病,提高人体免疫力和消炎、抗癌等功能。寇氏隐甲藻
(Crypthecodinium cohnii)细胞油脂富含 DHA,而其他多不饱和脂肪酸(PUFAs)含
量较少,可以在添加了有机底物的培养基中异养生长,是人体补充 DHA 的良好来源。
研究了温度和培养基的初始 pH 值对寇氏隐甲藻生长和油脂积累的影响。高温有
利于细胞的生长,30℃发酵培养的生物量最大,达到 ;低温有利于油脂的积
累,15℃条件下发酵,藻体内油脂含量达到 40%。将整个发酵过程分为两个阶段,
即 28℃条件下培养 5 天,然后在 22℃条件下再培养 2 天,油脂总产量达到 ,
这种温度变化的两阶段发酵过程较恒温发酵油脂产量高。培养基的初始 pH 值在
~ 时,生长速率最快,但油脂的积累对培养基的初始 pH 值的依赖性不是很强。
对培养基中葡萄糖、味精和酵母膏进行优化,得到葡萄糖的最佳浓度为 68g/L,
味精的最佳浓度为 30g/L,酵母膏的最佳浓度为 。在最佳配方下,DHA 的最终
产量达到 。
测定了寇氏隐甲藻的生长代谢曲线。发酵 7 天后收集藻体较为合理。
运用超声波法、生物酶法,反复冻溶法等方法,对寇氏隐甲藻进行了破壁研究。
研究表明,这些方法都对寇氏隐甲藻都具有一定的破壁作用,尤以碱性蛋白酶效果为
佳,破壁后油脂的提取率也有了不同程度的提高。把酶法破壁和超声波法破壁结合起
来,在酶解 5h 后,再超声波 1h,破壁率可高达 %,油脂提取率提高了 %,
破壁效果更为理想。

关键词:寇氏隐甲藻(Crypthecodinium cohnii);DHA(二十二碳六烯酸);形态特征;
发酵条件;培养基优化;生长代谢曲线;破壁
Study of Docosahexaenoic Acid Production by Crypthecodinium cohnii

Abstract
DHA is a polyunsaturated fatty acid that belongs to the ω-3 group. In recent years,
DHA has attracted much attention because it plays an important role in human health.
Crypthecodinium cohnii is extraordinary in DHA and it can be grown heterotrophically on
organic substrates without light. It is a prolific producer of DHA.
The effects of temperature and temperature shift on the biomass and oil content of
Crypthecodinium cohnii were investigated. Over the entire range of temperatures we have
studied, form 15℃ to 35℃, the microalga can grew well. High temperature is good for
growth and the highest biomass is at 30°C. In contrast, low temperature is good
for the accumulation of oil and the formation of polyunsaturated fatty acids and the highest
oil content is 40 percent. A shift from high temperature to low temperature at a later stage
of cultivation was also attempted. A temperature shift from 28℃(for 5 days) to 22℃(for 2
days) resulted in an increase in oil which was reach up to . When medium pH was
~, the highest