Diversity and occurrence of methylotrophic yeasts used in genetic engineering

Abstract

Methylotrophic yeasts have been used as the platform for expression of heterologous proteins since the  1980’s. They are highly productive and allow producing eukaryotic proteins with an acceptable glycosylation level.  The first Pichia pastoris-based system for expression of recombinant protein was developed on the basis of the treeexudate-derived strain obtained in the US southwest. Being distributed free of charge for scientific purposes, this system has become popular around the world. As methylotrophic yeasts were classified in accordance with biomolecular  markers, strains used for production of recombinant protein were reclassified as Komagataella phaffii. Although patent  legislation suggests free access to these yeasts, they have been distributed on a contract basis. Whereas their status  for commercial use is undetermined, the search for alternative stains for expression of recombinant protein continues.  Strains of other species of methylotrophic yeasts have been adapted, among which the genus Ogataearepresentatives prevail. Despite the phylogenetic gap between the genus Ogataeaand the genus Komagataellarepresentatives, it turned out possible to use classic vectors and promoters for expression of recombinant protein in all cases. There  exist expression systems based on other strains of the genus Komagataellaas well as the genus Candida. The potential  of these microorganisms for genetic engineering is far from exhausted. Both improvement of existing expression systems and development of new ones on the basis of strains obtained from nature are advantageous. Historically, strains  obtained on the southwest of the USA were used as expression systems up to 2009. Currently, expression systems  based on strains obtained in Thailand are gaining popularity. Since this group of microorganisms is widely represented  around the world both in nature and in urban environments, it may reasonably be expected that new expression systems for recombinant proteins based on strains obtained in other regions of the globe will appear.