Data for Determining Mating Type and Ploidy in Rhodotorula toruloides and its Effect on Growth on Sugars from Lignocellulosic Biomass

Rhodotorula toruloides is being developed for the use in industrial biotechnology processes because of its favorable physiology. This includes its ability to produce and store large amounts of lipids in the form of intracellular lipid bodies. Nineteen strains were characterized for mating type, ploidy, robustness for growth, and accumulation of lipids on inhibitory switchgrass hydrolysate (SGH). Mating type was determined using a novel polymerase chain reaction (PCR)-based assay, which was validated using the classical microscopic test. Three of the strains were heterozygous for mating type (A1/A2). Ploidy analysis revealed a complex pattern. Two strains were triploid, eight haploid, and eight either diploid or aneuploid. Two of the A1/A2 strains were compared to their parents for growth on 75%v/v concentrated SGH. The A1/A2 strains were much more robust than the parental strains, which either did not grow or had extended lag times. The entire set was evaluated in 60%v/v SGH batch cultures for growth kinetics and biomass and lipid production. Lipid titers were 2.33–9.40 g/L with a median of 6.12 g/L, excluding the two strains that did not grow. Lipid yields were 0.032–0.131 (g/g) and lipid contents were 13.5–53.7% (g/g). Four strains had significantly higher lipid yields and contents. One of these strains, which had among the highest lipid yield in this study (0.131 ± 0.007 g/g), has not been previously described in the literature.

鉴于其优异的生理特性，红冬孢酵母（Rhodotorula toruloides）正被开发用于工业生物技术流程，其优势包括能够产生并以细胞内脂滴（intracellular lipid bodies）的形式储存大量脂质。本研究对19株菌株的交配型、倍性、生长鲁棒性以及在抑制性柳枝稷水解液（switchgrass hydrolysate, SGH）中的脂质积累能力进行了表征。交配型通过基于聚合酶链式反应（polymerase chain reaction, PCR）的新型检测方法确定，并通过经典显微测试对该方法进行了验证。其中3株菌株的交配型为杂合型（A1/A2）。倍性分析结果显示出复杂的分布模式：2株为三倍体，8株为单倍体，另有8株为二倍体或非整倍体。选取2株A1/A2型菌株与其亲本菌株，对比其在75%体积分数浓缩SGH中的生长情况，结果显示A1/A2型菌株的生长鲁棒性显著强于亲本菌株——亲本菌株要么无法生长，要么出现显著延长的迟滞期。随后对全部19株菌株在60%体积分数SGH分批培养体系中开展生长动力学、生物量及脂质生产性能评估。剔除2株无法生长的菌株后，脂质滴度范围为2.33~9.40 g/L，中位数为6.12 g/L；脂质得率范围为0.032~0.131（g/g），脂质含量范围为13.5%~53.7%（g/g）。其中4株菌株的脂质得率与含量均显著高于整体水平，本研究中脂质得率最高的菌株之一（0.131±0.007 g/g）此前未见文献报道。