Metabolic engineering of Yarrowia lipolytica for thermoresistance and enhanced erythritol productivity

Abstract

Background Functional sugar alcohols have been widely used in the food, medicine, and pharmaceutical industries for their unique properties. Among these, erythritol is a zero calories sweetener produced by the yeast Yarrowia lipolytica. However, in wild-type strains, erythritol is produced with low productivity and yield and only under high osmotic pressure together with other undesired polyols, such as mannitol or d-arabitol. The yeast is also able to catabolize erythritol in non-stressing conditions. Results Herein, Y. lipolytica has been metabolically engineered to increase erythritol production titer, yield, and productivity from glucose. This consisted of the disruption of anabolic pathways for mannitol and d-arabitol together with the erythritol catabolic pathway. Genes ZWF1 and GND encoding, respectively, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were also constitutively expressed in regenerating the NADPH2 consumed during erythritol synthesis. Finally, the gene RSP5 gene from Saccharomyces cerevisiae encoding ubiquitin ligase was overexpressed to improve cell thermoresistance. The resulting strain HCY118 is impaired in mannitol or d-arabitol production and erythritol consumption. It can grow well up to 35 °C and retain an efficient erythritol production capacity at 33 °C. The yield, production, and productivity reached 0.63 g/g, 190 g/L, and 1.97 g/L·h in 2-L flasks, and increased to 0.65 g/g, 196 g/L, and 2.51 g/L·h in 30-m3 fermentor, respectively, which has economical practical importance. Conclusion The strategy developed herein yielded an engineered Y. lipolytica strain with enhanced thermoresistance and NADPH supply, resulting in a higher ability to produce erythritol, but not mannitol or d-arabitol from glucose. This is of interest for process development since it will reduce the cost of bioreactor cooling and erythritol purification.

The Role of Hexokinase and Hexose Transporters in Preferential Use of Glucose over Fructose and Downstream Metabolic Pathways in the Yeast Yarrowia lipolytica

“…Sci. 2021, 22, x FOR PEER REVIEW 12 of 20 from fructose (Figure 5), carried out by mannitol dehydrogenase [33,34], which also coincided with the period of high-rate fructose consumption. We were curious to whether the polyol spectrum could be changed by further optimization of culture conditions.…”

“…On the other hand, when grown on glucose and fructose, mannitol was predominant, followed by significant amounts of erythritol and arabitol. In these conditions, increased mannitol biosynthesis could be expected as it is only one metabolic step from fructose (Figure 5), carried out by mannitol dehydrogenase [33,34], which also coincided with the period of high-rate fructose consumption. Int.…”

Overexpression of YALI0B07117g Encoding Erythrose Reductase Homolog Results in Enhanced Erythritol Synthesis From Glycerol by the Yeast Yarrowia Lipolytica.

“…Additionally, 8 homologs of ER were characterized. Similarly the d-mannitol dehydrogenase gene (YALI0B16192g) was reported by Wang et al (2020).…”

“…The discrepancy between the mannitol and arabitol production in the overexpression and knock-out mutant in comparison with the WT strain indicates the signi cance of the role of YALI0B07117g in synthesis of these polyols. The characterization of genes responsible for mannitol synthesis by Y. lipolytica [23] from glycerol is necessary not only to overcome the problem of puri cation of erythritol due to the byproducts in the medium but also to decipher the mannitol synthesis pathway. The strain AJD ΔB07117 may be used to analyze the genes involved in mannitol synthesis and become a potential asset in future research to obtain a Y. lipolytica strain able to produce mannitol from glycerol with high values of yield and productivity.…”

Correction to: Metabolic engineering of Yarrowia lipolytica for thermoresistance and enhanced erythritol productivity

“…The correct author name is: Muhammad Bilal. The author group has been updated above and the original article [1] has been corrected.…”