Synthetic Methylotrophy in Yeasts: Towards a Circular Bioeconomy

The Identification of Genetic Determinants of Methanol Tolerance in Yeast Suggests Differences in Methanol and Ethanol Toxicity Mechanisms and Candidates for Improved Methanol Tolerance Engineering

“…Methanol is a promising feedstock alternative to sugar-based raw materials for the bioproduction of fuels, specialty chemicals, polymers, and other value-added products due to its abundance and relatively low cost [ 1 , 2 , 3 , 4 ]. Methanol is also the major impurity in crude glycerol, reaching relatively high levels that can vary considerably from batch to batch and, although it can be removed by evaporation, this process is energy demanding [ 5 , 6 ].…”

“…Differently from methylotrophic yeast species, the preferred yeast cell factory Saccharomyces cerevisiae , is not able to use methanol as sole carbon source but there are successful examples of S. cerevisiae metabolic engineering for direct methanol utilization [ 2 , 10 , 11 ]. Although being a promising carbon source for metabolically competent yeast strains, methanol toxicity can limit the productivity of methanol-based biomanufacturing [ 3 ]. For this reason, the identification of genes/proteins whose expression is required for maximum tolerance to methanol in the model yeast species S. cerevisiae is important for enlightening the mechanisms underlying methanol toxicity in methylotrophic yeasts and in other eukaryotes as well as for guiding the development of more robust yeast strains, in particular methylotrophic yeast strains [ 3 ].…”

“…Although being a promising carbon source for metabolically competent yeast strains, methanol toxicity can limit the productivity of methanol-based biomanufacturing [ 3 ]. For this reason, the identification of genes/proteins whose expression is required for maximum tolerance to methanol in the model yeast species S. cerevisiae is important for enlightening the mechanisms underlying methanol toxicity in methylotrophic yeasts and in other eukaryotes as well as for guiding the development of more robust yeast strains, in particular methylotrophic yeast strains [ 3 ]. Genome-wide approaches have been enabling a holistic view and a deeper understanding of the molecular mechanisms and signaling pathways involved in the global response and adaptation of yeasts to sublethal concentrations of toxicants by allowing the identification of genes and pathways involved in the toxicological response and required for maximum tolerance [ 12 , 13 ].…”

Metabolic regulation adapting to high methanol environment in the methylotrophic yeast Ogataea methanolica

“…Among them, methylotrophic yeasts, such as Komagataella phaffii (formerly Pichia pastoris [Kurtzman, 2005]), Candida boidinii , Ogataea polymorpha (formerly Hansenula polymorpha [Yamada et al, 1994]), and Ogataea methanolica (formerly Pichia methanolica [Kurtzman and Robnett, 1998]), have high potential as fermentation producers for several biomass conversions from methanol. They are recognized as attractive hosts for the production of heterologous protein for the following reasons: (i) the yeast is easy to grow to a high‐density culture; (ii) abundant molecular genetic tools are available; (iii) the yeast has strong methanol‐inducible promoters for the gene expression system; (iv) the yeast has the advantages of performing extensive post‐translational modifications, protein folding and secretion of recombinant targets; and (v) the yeast possesses higher tolerance to extreme (acidic and basic) pH conditions (Porro et al ., 2005; Cos et al ., 2006; Yurimoto et al ., 2011; Palma et al ., 2018; Tan et al, 2018; Patiño et al ., 2019; Fabarius et al, 2021).…”

Fatty acid composition of the methylotrophic yeast Komagataella phaffii grown under low‐ and high‐methanol conditions

“…Among the methylotrophs, certain methylotrophic yeast species, including Komagataella phaffii (formerly Pichia pastoris [Kurtzman, 2005]), Candida boidinii , Ogataea polymorpha (formerly Hansenula polymorpha [Yamada et al, 1994]) and Ogataea methanolica (formerly Pichia methanolica [Kurtzman & Robnett, 1998]), are recognized as attractive hosts for the production of heterologous protein and as fermentation producers for several biomass conversions from methanol, because (i) these yeasts easily grow into high‐density cultures, (ii) abundant molecular genetic tools have been developed for them and (iii) these yeasts have strong methanol‐inducible promotors for the gene expression system (Cos et al, 2006; Fabarius et al, 2021; Gellissen et al, 2005; Hartner & Glieder, 2006; Raymond et al, 1998; Yurimoto, 2009; Yurimoto et al, 2011). K. phaffii in particular is one of the most widely used methylotrophic yeast species in several industries (Fabarius et al, 2021).…”