Scheffersomyces stambukii f.a., sp. nov., a d-xylose-fermenting species isolated from rotting wood

Abstract

Two isolates representing a new species of Scheffersomyces were isolated from rotting wood samples collected in an Amazonian forest ecosystem in Brazil. Analysis of the sequences of the D1/D2 domains showed that this new species is phylogenetically related to Scheffersomyces NYMU 15730, a species without a formal description, and the two are in an early emerging position with respect to the xylose-fermenting subclade containing Scheffersomyces titanus and Scheffersomyces stipitis. Phylogenomic analyses using 474 orthologous genes placed the new species in an intermediary position between Scheffersomyces species and the larger genus Spathaspora and the Candida albicans/Lodderomyces clade. The novel species, Scheffersomyces stambukii f.a., sp. nov., is proposed to accommodate these isolates. The type strain of Scheffersomyces stambukii sp. nov. is UFMG-CM-Y427 (=CBS 14217). The MycoBank number is MB 824093. In addition, we studied the xylose metabolism of this new species.

Three new Scheffersomyces species associated with insects and rotting wood in China

“…Two strains, representing S. anoplophorae , were clustered in a well-supported clade and were phylogenetically related to S. stambukii ( Lopes et al 2018 ). The nucleotide differences between the new species and its closest relative, S. stambukii , were 2.3% substitutions in the D1/D2 domain and 6.6% substitutions in the ITS region, respectively.…”

“…Yeasts of the genus Scheffersomyces have been found to occupy habitats rich in xylose, including rotting wood ( Ren et al 2013 ; Lopes et al 2018 ), wood-feeding insects ( Suh et al 2013 ; Urbina et al 2013 ; Liu et al 2016b ), and the resulting frass ( Lachance et al 2011 ). We have reported the isolation and identification of several d-xylose-fermenting yeasts from wood-feeding insects and rotting wood ( Ren et al 2013 ; Liu et al 2016b ), including those detailed in this study.…”

“…The genus Scheffersomyces was later expanded by including seven related Candida species as new combinations and by three novel species, S. illinoinensis , S. quercinus , and S. virginianus , which were discovered in rotting wood ( Urbina and Blackwell 2012 ). More recently, several new species and combinations from the genus Scheffersomyces , ( S. cryptocerci , S. parashehatae , S. titanus , and S. xylosifermentans ) have been identified in wood-ingesting insects ( Suh et al 2013 ; Urbina et al 2013 ; Liu et al 2016b ), and in rotting wood ( S. amazonensis , S. ergatensis , S. henanensis , and S. stambukii ) ( Ren et al 2013 ; Urbina and Blackwell 2013 ; Lopes et al 2018 ). This genus comprises 21 species, though the status of S. gosingicus and S. lignicola is currently unclear due to nomenclatural issues regarding the Melbourne Code (Index Fungorum, accessed 17.07.2020).…”

“…This genus comprises 21 species, though the status of S. gosingicus and S. lignicola is currently unclear due to nomenclatural issues regarding the Melbourne Code (Index Fungorum, accessed 17.07.2020). Of the 19 valid species, five of them are known to form ascospores ( Kurtzman 2011 ; Ren et al 2013 , Liu et al 2016b ) and 14 of them display asexual morphs ( Urbina and Blackwell 2012 ; Suh et al 2013 ; Urbina and Blackwell 2013 ; Urbina et al 2013 ; Lopes et al 2018 ).…”

“…Asexual reproduction occurs via multilateral budding on a narrow base; sexual reproduction occurs via the formation of 1–2 hat-shaped ascospores released soon after formation ( Kurtzman 2011 ). Several Scheffersomyces species, such as S. henanensis , S. shehatae , and S. stipitis , strongly ferment d-xylose, which is important for producing bioethanol from the residue of plant waste ( du Preez and van der Walt 1983 ; Agbogbo and Wenger 2006 ; Ren et al 2013 ; Suh et al 2013 ; Lopes et al 2018 ). Despite the existence of these microbes, obtaining high ethanol yields from pentose sugars on a large scale remains a challenge ( Chandel et al 2011 ) because scientists have yet to identify microbes that convert pentose sugars into ethanol at high yields, while withstanding fermentation inhibitors ( Agbogbo and Wenger 2006 ; Long et al 2012 ).…”