混合糖发酵产油脂酵母菌的筛选及脂肪酸组成分析

Screening of oil-producing yeast strains by co-fermentation of glucose and xylose and lipid-acid component analysis

从海南土壤中分离的12株野生酵母菌株中,筛选到一株能够利用混合糖发酵高产油脂的酵母菌株YP-32,在葡萄糖∶木糖(质量比)为2∶1条件下发酵120 h,生物量、油脂产量和油脂含量达到最大,分别为22.33g/L、13.39 g/L和60.42%;该菌株利用5种不同比例混合糖产油脂的脂肪酸组成均以C_(16)和C_(18)系脂肪酸为主,其中油酸含量最高,其次为棕榈酸和硬脂酸,这3种脂肪酸含量占总脂肪酸含量的90%以上,与植物油脂脂肪酸组成相似,可以作为生物柴油油源。通过形态特征及26S rDNA D1/D2和ITS区域序列分析,初步鉴定菌株YP-32为油脂酵母属的Lipomyces orientalis,为我国分布新纪录。

In this paper, the strain YP-32 which could use mixed sugar of glucose and xylose as carbon source to produce lipid were screened from 12 wild yeast strains from the soil of Hainan province. The biomass, lipid concentra- tion and lipid content of the strain reached 22.33 g/L, 13.39 g/L and 60.42% respectively by fermenting with 2：1 of glucose and xylose as carbon source. Simultaneously, lipid-acid component was analyzed. There was almost no difference in lipid-acids component by using different mixed sugar ratios as carbon source. Results showed that C l6 and C18 series were main fatty acids. Oleic acid content was the highest, palmitic acid and stearic acid were next in all samples and the sum of them accounted for over 90% of total content of lipid acids. The lipid component of this strain was similar to plant oil and could be used as biodiesel source. The strain was primarily identified as Lipomyces orientalis by the morphology feature, 26S rDNA D1/D2 and ITS domain sequence analysis. The strain is a new record for distribution in our country.