添加餐厨废油脂培养酵母进行γ-癸内酯生物转化

Biotransformation of γ-decalactone from kitchen waste oil by yeasts

为了降低工业化生产γ-癸内酯(γ-decalactone,GDL)的成本,利用餐厨废弃油脂代替部分培养基成分培养解脂耶氏酵母(Yarrowia lipolytica),当添加餐厨废弃油脂6 g/L,葡萄糖由20 g/L降为12.5 g/L,酵母提取物由10 g/L降为5 g/L时,培养12 h后获得与完全培养基相当的生物量。在Y.lipolytica中过表达酰基辅酶A氧化酶基因pox2获得工程菌,将蓖麻油酸转化为GDL产量达1.5 g/L,是出发菌株的2.2倍。利用分解油脂活性高的Y.lipolytica菌株(解脂假丝酵母Candida lipolytica CICC31223)与工程菌混菌降解餐厨废弃油脂并转化蓖麻油生产GDL,最佳条件为:当C.lipolytica与Y.lipolytica工程菌的接种比例为1∶10(体积比)、接种方式为先接种C.lipolytica,28℃,振荡培养(200 r/min)12 h后再接种Y.lipolytica,混菌发酵培养基中GDL产量达0.15 g/L,显著高于工程菌单菌发酵产量0.08 g/L。结果表明,餐厨废弃油脂是廉价的碳源,通过不同菌株的混菌发酵转化生产GDL的方法具有很大的工业化应用前景。

In order to reduce the cost of industrial production ofγ-decalactone(GDL),the feasibility of kitchen waste oil as carbon sourcewas studied.Equivalent biomass of Yarrowia lipolytica in complete medium was gained after 12 h cultivation under the optimized medium consisted of 12.5 g/L glucose,5 g/L yeast extract and 6 g/L kitchen waste oil.Engineered Y.lipolytica overexpressing acetyl-CoA oxidase gene pox2 produced 1.5g/L of GDL from ricinoleic acid was,which was 1.2 times higher than that of parent strain.Y.lipolytica CICC31223 with high lipase-producing ability was co-cultured with the engineered strain for efficient degradation of waste oil and transforming castor oil into GDL.The optimal production conditions were determined as follows:inoculation ratio of Y.lipolytica CICC31223 to Y.lipolytica was 1∶10(V/V),Y.lipolytica was inoculated after culturing Y.lipolytic CICC31223 for 12 h at 28℃at 200 r/min.It was found that the level of GDL reached 0.15 g/L at above optimal conditions and it was significantly higher than single culture production(0.08 g/L).The results suggested that the kitchen waste oil is an economical carbon source and producing GDL by mixed fermentation of yeasts has great industrial application prospects.