The expression of glycerol facilitators from various yeast species improves growth on glycerol of Saccharomyces cerevisiae

Abstract

Glycerol is an abundant by-product during biodiesel production and additionally has several assets compared to sugars when used as a carbon source for growing microorganisms in the context of biotechnological applications. However, most strains of the platform production organism Saccharomyces cerevisiae grow poorly in synthetic glycerol medium. It has been hypothesized that the uptake of glycerol could be a major bottleneck for the utilization of glycerol in S. cerevisiae. This species exclusively relies on an active transport system for glycerol uptake. This work demonstrates that the expression of predicted glycerol facilitators (Fps1 homologues) from superior glycerol-utilizing yeast species such as Pachysolen tannophilus, Komagataella pastoris, Yarrowia lipolytica and Cyberlindnera jadinii significantly improves the growth performance on glycerol of the previously selected glycerol-consuming S. cerevisiae wild-type strain (CBS 6412-13A). The maximum specific growth rate increased from 0.13 up to 0.18 h−1 and a biomass yield coefficient of 0.56 gDW/gglycerol was observed. These results pave the way for exploiting the assets of glycerol in the production of fuels, chemicals and pharmaceuticals based on baker's yeast.

Glycerol metabolism and transport in yeast and fungi: established knowledge and ambiguities

“…In order to directly compare these yeast species to each other and to S. cerevisiae , we recently performed a growth analysis in synthetic medium containing 6% (v/v) glycerol. One representative strain of Y. lipolytica, C. jadinii, P. tannophilus and K. pastoris was tested, and the values for μ max observed under these conditions were 0.50, 0.42, 0.27 and 0.20 h −1 respectively (Klein et al ., ). Under the same conditions, the best performing wild‐type isolates of the species S. cerevisiae showed growth rates on glycerol of up to 0.15 h −1 (Swinnen et al ., ).…”

Overexpression of the genes of glycerol catabolism and glycerol facilitator improves glycerol conversion to ethanol in the methylotrophic thermotolerant yeast Ogataea polymorpha

“…As was already mentioned in Section , there is limited information on glycerol uptake in O. polymorpha . However, it was shown that introduction of heterologous transporter Fps1 from the yeast K. phaffii in S. cerevisiae improves glycerol utilization in this yeast (Klein et al, ). We attempted to find out glycerol transporters homologs in O. polymorpha .…”

“…However, no homologs of Fps1 protein were found in the O. polymorpha database . Nevertheless, we decided to use heterologous gene encoding Fps1 protein, because glycerol transporting capacity of Stl1 in S. cerevisiae is quite low (Klein et al, ). Gene FPS1 of K. phaffii encoding glycerol facilitator was expressed in our best ethanol producing strains.…”

“…The commonly used ethanol producer baker yeast Saccharomyces cerevisiae has very low capability to utilize glycerol as a sole carbon source, especially in a synthetic medium with no growth‐supporting supplements (such as amino acids and nucleic bases; Swinnen et al, ). The growth of S. cerevisiae on glycerol can be improved, though, by evolutionary adaptation (Ochoa‐Estopier, Lesage, Gorret, & Guillouet, ) or expression of heterologous glycerol transporters (Klein et al, ). Some new microorganisms with good ability to grow and produce ethanol on crude glycerol have been recently isolated, for example, the bacterium Kluyvera cryocrescens (Choi, Hartono, Chan, & Yeo, ) and the yeast Pachysolen tannophilus (Liu, Jensen, & Workman, ).…”

“…For example, it was shown that the expression of FPS2 gene from P. tannophilus in S. cerevisiae resulted to relief the inability of the stl1Δ mutant to grow on glycerol, whereas overexpression of the homologous S. cerevisiae FPS1 did not (Liu et al, ). Later, the expression of FPS1 homologs from different nonconventional yeast species ( Cyberlindnera jadinii , K. phaffii , and Yarrowia lipolytica ) was performed in S. cerevisiae , and the resulted recombinant strains had much higher growth rates on glycerol in comparison to the parental strain (Klein et al, ). There is no reliable data regarding glycerol uptake in O. polymorpha (Figure ).…”