A novel strain of Yarrowia lipolytica as a platform for value-added product synthesis from glycerol

Abstract

BackgroundIncreasing interest of non-conventional yeasts has been observed for many years due to their biochemical characteristics and potential applications. Well-studied, oleaginous yeast Y. lipolytica is an attractive host for converting a low-cost glycerol, into value-added products such as erythritol (sweetener) or citric acid. Glycerol is an important renewable feedstock and is the main co-product of biodiesel production, which is nowadays applied on a large commercial scale. To this end, we engineered the yeast Y. lipolytica to increase the productivity of this strain.ResultsIn this light, we enhanced glycerol assimilation by over-expression of the YALI0F00484g gene encoding glycerol kinase (GK) and gene YALI0B02948g encoding glycerol-3-P dehydrogenase (GDH). The modified strains have been tested for glycerol consumption rate and erythritol and citric acid synthesis under various conditions. Here, we show that the overexpression of GK and GDH, increased glycerol consumption resulting in rapid erythritol and citric acid synthesis. Next, we combined the two genes in the tandem gene construct for the simultaneous co-expression of GK and GDH, which further increased the desired product synthesis. The glycerol consumption was explored in a 5-L bioreactor and the engineered strains were able to utilize 150 g/L glycerol within 44–48 hours. The erythritol productivity for GK overexpression and co-expression of GK and DGH was 24 and 35 %, respectively, over the control strain. Moreover, we established conditions for the production of citric acid at pH 3.0, the engineered strains increased citric acid production 14-fold over the control.ConclusionThis work demonstrates the excellent capacity of the engineered strains as a starting platform for further modification for broad-range value-added product biosynthesis from glycerol. This study presents the highest reported titer citric acid at low pH to date. The process parameters such as productivity and yield of erythritol and citric acid were significantly elevated, what is valuable for industrial applications.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0593-z) contains supplementary material, which is available to authorized users.

Enhancing erythritol productivity in Yarrowia lipolytica using metabolic engineering

“…Despite the some of these processes have been developed at industrial scale, they suffer from the high cost of the fermentation media and the production of unwanted byproducts such as mannitol, and organic acids which renders the downstream processing more challenging. Recently, Yarrowia lipolytica has also been found to be an efficient erythritol producer (Rymowicz et al, 2008;Yang et al, 2014;Park et al, 2016;Mirończuk et al, 2016).…”

Kinetic models application on glycerol production from glucose by the marine yeast Candida orthopsilosis

“…Higher glycerol yields have been obtained from species that show a relatively strong tolerance for high concentration of sugars and salts (Loray et al, 1995;Patil, 2013). Selection of yeast strains and optimization of fermentation conditions such especially the carbon source are critical parameters for glycerol overproduction (Ehsani et al, 2009;Orlic et al,2010;Mirończuk et al, 2016;Singh et al, 2016;Hawary et al, 2019). In this study, screening of some marine yeast isolates for glycerol production was performed.…”

Erythritol production by yeasts: a snapshot of current knowledge

“…The yield was also higher, with a value of 0.52 g/g. Moreover, this strain showed higher glycerol uptake (Mirończuk, Rzechonek, Biegalska, Rakicka, & Dobrowolski, 2016).…”

“…The yield was also higher, with a value of 0.52 g/g. Moreover, this strain showed higher glycerol uptake (Mirończuk, Rzechonek, Biegalska, Rakicka, & Dobrowolski, ). Strains overexpressing both transketolase and ER also showed important benefits as compared with wild‐type strains, highlighting the central gene of these genes in erythritol synthesis (Janek et al, ; Mirończuk et al, ).…”