Department of Materials and Bioprocess Engineering, School of Chemical Engineering, State University of Campinas, Campinas, SP, 13083-852, Brazil.
Institute of Technology, University of Tartu, Tartu, Estonia.
Appl Microbiol Biotechnol. 2021 Dec;105(24):9261-9272. doi: 10.1007/s00253-021-11687-z. Epub 2021 Nov 11.
The oleaginous yeast Rhodotorula toruloides is a potential lipid producer for biodiesel production. However, this yeast shows growth inhibition due to harmful compounds when cultivated in hemicellulose hydrolysate. Here, we present a comparative analysis of colony selection and heterologous adaptive laboratory enhancement (ALE) strategies for obtaining robust strains. We implemented these ALE strategies for R. toruloides in a culture medium containing sugarcane hemicellulose hydrolysate. Our comparison study showed that the strain obtained with heterogeneous ALE strategy (Rth) reached a µ of 55% higher than the parental strain. It also exhibited higher biomass production (6.51 g/l) and lipid content (60%). ALE with colony selection strategy (Rtc) had a fitness gain in terms of shortening of the lag phase (9 h) when compared to Rth and parental strain (11.67, 12.33 h, respectively). When cultivated in Eucalyptus urograndis hemicellulose hydrolysate, the Rth strain achieved a high lipid content, 64%. Kinetics studies showed a strong effect of acetic acid as a repressor of xylose consumption during R. toruloides cultivation.Key points• Distinct adaptive laboratory strategies resulted in strains with different physiologies.• Heterologous adaptive laboratory enhancement provided the best results (fitness gain of 55% in µmax).• The Rth strain achieved a lipid content of 64.3% during cultivation in eucalyptus hemicellulose hydrolysate.
油脂酵母罗伦隐球酵母是生产生物柴油的有潜力的油脂生产菌。然而，当在半纤维素水解物中培养时，该酵母由于有害物质的存在而表现出生长抑制。在这里，我们对集落选择和异源适应性实验室增强（ALE）策略进行了比较分析，以获得稳健的菌株。我们在含有甘蔗半纤维素水解物的培养基中对罗伦隐球酵母实施了这些 ALE 策略。我们的比较研究表明，采用异质 ALE 策略（Rth）获得的菌株µ值比原始菌株高 55%。它还表现出更高的生物量生产（6.51 g/l）和脂质含量（60%）。与 Rth 和原始菌株相比，采用集落选择策略（Rtc）的 ALE 在延滞期（分别为 9 h、11.67 h 和 12.33 h）方面具有缩短的优势。当在桉树木材半纤维素水解物中培养时，Rth 菌株实现了 64%的高脂质含量。动力学研究表明，在罗伦隐球酵母培养过程中，乙酸作为木糖消耗的抑制剂具有很强的作用。
关键点
• 不同的适应性实验室策略导致了具有不同生理特性的菌株。
• 异源适应性实验室增强提供了最佳结果（µmax 提高了 55%）。
• 在桉树半纤维素水解物中培养时，Rth 菌株的脂质含量达到 64.3%。
