Biodiesel is a useful alternative source of energy and can be used as a support for oil-source diesel. Microbial lipids are considered a promising raw material for biodiesel production. In a previously completed study, Pichia cactophila was found to be the best lipid-producing yeast by lipid screening studies among 107 yeast isolates. In this study, the lipid production conditions of P. cactophila, which was chosen as a lipid producer for the first time, were partially optimized by using response surface methodology in crude glycerol. Plackett-Burman statistical experiment design was used to determine the effect of glycerol, yeast extract, peptone, urea, (NH₄)₂SO₄, NH₄Cl, NH₄NO₃ factors on lipid production. In order to determine the optimum levels of the most effective parameters by the result of screening (glycerol, yeast extract, urea, NH₄NO₃), Box-Behnken experimental design method was used. The optimum production conditions were determined as 39 g/L glycerol, 20 g/L yeast extract, 5 g/L urea, and 20 g/L NH₄NO₃, and the result of the experiments carried out under these conditions the lipid value (%) was determined as 91.43. Lipid content was increased 1.408-fold (40.79%) by two-step optimization with the response surface methodology and reached a very high value. The fatty acid composition obtained under optimum conditions is compatible with vegetable oils. This suggests that the microbial lipid of P. cactophila can be used as a raw material for biodiesel production and is promising for further studies.

Graphical abstract

中文翻译：

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提高新型天然油质酵母的脂质生产能力：首先是仙人掌毕赤酵母

生物柴油是一种有用的替代能源，可以用作石油柴油的载体。微生物脂质被认为是生物柴油生产的有前途的原料。在先前完成的一项研究中，通过107种酵母分离株中的脂质筛选研究，发现仙人掌毕赤酵母是产生脂质最多的酵母。在这项研究中，通过在粗甘油中使用响应面方法，部分地优化了首次被选为脂质生产者的仙人掌假单胞菌的脂质生产条件。使用Plackett-Burman统计实验设计确定甘油，酵母提取物，蛋白p，尿素，（NH ₄）₂ SO ₄，NH ₄ Cl，NH的作用₄ NO ₃影响脂质产生的因素。为了通过筛选结果（甘油，酵母提取物，尿素，NH ₄ NO ₃）确定最有效参数的最佳水平，使用了Box-Behnken实验设计方法。确定了最佳生产条件为：39 g / L甘油，20 g / L酵母提取物，5 g / L尿素和20 g / L NH ₄ NO ₃，并且在这些条件下进行的实验结果，脂质值（％）被确定为91.43。通过使用响应面方法进行两步优化，脂质含量增加了1.408倍（40.79％），并达到了很高的值。在最佳条件下获得的脂肪酸组成与植物油相容。这表明，仙人掌假单胞菌的微生物脂质可以用作生产生物柴油的原料，并有望用于进一步的研究。

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