氮源种类及溶氧水平对锁掷酵母产类胡萝卜素组分的影响

Effects of nitrogen source and dissolved oxygen level on production of carotenoids by Sporidiobolus pararoseus

在锁掷酵母(Sporidiobolus pararoseus)发酵产类胡萝卜素的过程中,发酵产物中类胡萝卜素种类繁多,而且性质相似,加大了不同色素分离纯化的难度。为定向积累不同种类的类胡萝卜紊,以本实验室保藏锁掷酵母JD-2为出发菌,研究了氮源种类和浓度及溶氧对锁掷酵母产类胡萝卜素的影响,并在7 L发酵罐中进行了补料分批发酵试验。发现培养基中同时添加有机氮源和无机氮源且溶氧控制较低(5%)时有利于β-胡萝卜素的大量积累,最佳有机氮源和无机氮源分别为玉米浆(20 g/L)、硫酸铵(5 g/L)。补料分批发酵时β-萝卜素产量达到31.28 mg/L,红酵母烯12.38mg/L。培养基中只添加有机氮源且相对溶氧控制相对较高(30%)时有利于红酵母烯的大量积累,最佳有机氮源为酵母膏(20 g/L)。补料分批发酵时红酵母烯产量达到38.96 mg/L,β-胡萝卜素12.36 mg/L。

In the process of producing carotenoids by Sporidiobolus pararoseus, there are different kinds of carotenoids in fermentation products. It increased the difficulty in purifying these carotenoids because of their similar properties. In order to accumulate different kinds of carotenoids, the effects of nitrogen source and dissolved oxygen on the production of differ- ent kinds of carotenoids by S. pararoseus JD-2 were investigated and the fed-batch fermentation in a 7 L fermenter was test- ed. The results showed that it was conducive to accumulation of B-carotene when both organic nitrogen source and inorgan- ic nitrogen source were added to medium and kept dissolved oxygen at low level （5%）. The optimal organic nitrogen source and inorganic nitrogen source were corn steep liquor （20 g/L） and ammonium sulfate （5 g/L） , respectively. The β-carotene and torulene could reach 31.28 mg/L and 12.38 mg/L respectively in the fed-batch fermentation test. On the other hand, it would be benefit for the accumulation of torulene, if merely organic nitrogen was added to the medium and kept the dissolved oxygen at high level （30%）. The optimal organic nitrogen was yeast extract （20 g/L）. The production of torulene would reach 38.96 mg/L, while the production of β-carotene decreased to 12.36 mg/L in the fed-batch fer- mentation test.