富油微藻的筛选及其产油能力的评价

Screening of oleaginous microalgae and assessment of its oil producing capability

【目的】筛选具有较快生长速率及较强产油能力的微藻,探究所获得微藻的生理生化性能及不同培养方式对其生物量、产油能力、碳消耗等生长特性的影响与藻种对pH的适应能力。【方法】通过磷酸香草醛测定法及尼罗红染色对微藻进行初筛复筛,通过设置光合自养、异养和混养等3种培养方式,并采用气质联用等方法,研究不同培养方式对所获微藻生长特性、所产油脂脂肪酸组成以及碳代谢等方面的影响。【结果】筛选出两株产油能力较强的藻株H、Z8,其油脂产量分别可达1.14±0.05 g/L和1.33±0.10 g/L,经形态观察和分子生物学鉴定初步表明藻株H属布朗单针藻(Chlorolobion braunii)、藻株Z8属链带藻(Desmodesmus intermedius)。构建了不同培养方式下微藻动力学模型,H、Z8属于生长偶联型。当培养环境的pH处于6.0–9.0,对藻株H、Z8的总脂量与生物量无明显差异(P<0.05)。【结论】筛选获得的藻株H、Z8中C16与C18脂肪酸占总脂肪酸的比率能达到90%以上。藻种在混养条件下生物量积累优于异养,但异养条件下更加有利于油脂的积累,且H、Z8均具有较为宽泛的pH适应能力,是具有一定产业化应用潜力的优良产油藻株。

[Objective]The purposed of this study is to obtain some microalgae with fast growth and high oil producing ability.In addition,the effects of different culture methods on microalgae growth characteristics such as biomass,oil producing capacity and carbon consumption,and the adaptation of strains to pH were studied.[Methods]The method of phosphoric acid-vanillin reaction and Nile Red staining was used for obtaining some oleaginous microalgae.At the same time,different culture methods such as photoautotrophy,heterotrophy and mixotrophy,were studied by using GC-MS technique.[Results]Two strains of H and Z8,which could produce 1.14±0.05 g/L and 1.33±0.10 g/L total lipid,respectively,were obtained.According to the results of morphological observations and 18 S rDNA analysis,strains H and Z8 had the highest homology with Chlorolobion braunii and Desmodesmus intermedius,so the strains were identified as Chlorolobion braunii H and Desmodesmus intermedius Z8.Furthermore,H and Z8 belonged to the growth coupling type based on the results of the kinetic model.There was no significant difference in the total lipid and biomass between H and Z8 when the pH value was between 6.0 and 9.0(P<0.05).The percentage of C16 and C18 fatty acids in total fatty acid from the strains H and Z8 was more than 90%.The biomass from mixotrophy was better than heterotrophy,but it was more conducive to lipid accumulation under heterotrophic conditions.Furthermore,the strains of H and Z8 have a wide pH adaptability.[Conclusion]These results indicate that the two strains are excellent potential lipid-producing strains.