多不饱和脂肪酸高产菌株的诱变选育

为获得多不饱和脂肪酸高产菌株，以深黄被孢霉（Mortierella isabellina）AS3.3410为出发菌株，利用紫外线（UV）及氯化锂（LiCl）对其进行复合诱变，通过乙酰水杨酸初筛、苏丹黑B染色，摇瓶复筛，得到高产多不饱和脂肪酸突变菌株，并对其遗传稳定性和油脂组成成分进行分析。结果表明，筛选得到一株突变株SLZH-20，具有较好的遗传稳定性，其摇瓶发酵5 d时，生物量和油脂含量分别为22.76 g/L、52.30%，比出发菌株分别提高34.60%和24.30%；该菌株所产油脂中不饱和脂肪酸包括棕榈一烯酸、油酸、亚油酸、γ-亚麻酸、α-亚麻酸，含量为81.41%，多不饱和脂肪酸含量为16.24%，比出发菌株分别增加5.72%和2.18%。

Mutagenesis and breeding of high-yield polyunsaturated fatty acids strains

In order to obtain high-yield polyunsaturated fatty acid strains, using Mortierella isabellina AS3.3410 as the starting strain, composite mutagenesis was carried out by ultraviolet (UV) and lithium chloride (LiCl). The high-yield polyunsaturated fatty acid mutant strains were obtained by primary screening with acetylsalicylic acid and Sudan black B staining and re-screening with shaking flask, and their genetic stability and lipid composition were analyzed. The results showed that a mutant strain SLZH-20 was screened and showed good genetic stability. The biomass and lipid contents were 22.76 g/L and 52.30%, respectively, which were 34.60% and 24.30% higher than the starting strain after shaking flask fermentation for 5 d, respectively. The unsaturated fatty acids in the lipid produced by the strain including palmitoenoic acid, oleic acid, linoleic acid, γ-linolenic acid and α-linolenic acid were 81.41%. The polyunsaturated fatty acids contents were 16.24%, which were 5.72% and 2.18% higher than that of the starting strain, respectively.