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Supplemental Material for Arrey et al., 2021

journal contribution
posted on 22.09.2021, 15:36 by Gerard Arrey, Guangshuo Li, Robert Murphy, Leandro Guimeraes, Sefa Alizadeh, Michael Poulsen, Birgitte Regenberg

Bioconversion of hemicelluloses into simpler sugars leads to production of a significant amount of pentose sugars, such as D-xylose. However, efficient utilization of pentoses by conventional yeast production strains remains challenging, especially due to inhibition by hexose co-fermentation. Wild yeast strains can provide new industrially relevant characteristics to bypass these inhibitions and efficiently utilize pentose sugars. To explore this strategy, we isolated gut-residing yeasts from the termite Macrotermes bellicosus collected in Comoé National Park, Côte d´Ivoire. The yeasts were classified through their ITS and LSU sequence and genomes of three new strains and species were sequenced and annotated. We identified a novel yeast species, which we name Barnettozyma botsteinii sp. nov. 1118T (MycoBank: 833563, CBS 16679T and IBT 710) and two new strains of Kurtzmaniella quercitrusa: var. comoensis (CBS 16678, IBT 709) and var. filamentosus (CBS 16680, IBT 711). The two K. quercitrusa strains grow 15% faster on synthetic glucose medium than Saccharomyces cerevisiae CEN.PKT in acidic conditions (pH = 3.2) and both strains grow on D-xylose as the sole carbon source at a rate of 0.35 h-1. At neutral pH, the yeast form of K. quercitrusa var. filamentosus, but not var. comoensis, switched to filamentous growth in a carbon source dependent manner, revealing phenotypic diversity among strains within the species. The utilisation of plant-derived sugars by K. quercitrusa indicates the potential for a mutualistic relationship between this yeast and the termite. Besides its metabolism, K. quercitrusa var. filamentosus also has a large potential as a production organism, because of its capacity to grow at low pH and to undergo a dimorphic shift.

History

Article title

Isolation, characterisation and genome assembly of Barnettozyma botsteinii sp. nov. and novel strains of Kurtzmaniella quercitrusa isolated from the intestinal tract of the termite Macrotermes bellicosus