Comparative analysis of xylose consumption rate of different native pentose-consuming yeasts

BOLZICO, B; COMELLI, RN

Congreso; International Congress on Yeast (ICY); 2021

International Congress on Yeast (ICY)

Conversion of all sugars present at lignocellulosic biomass would increase production and reduce cost of second-generation ethanol. Saccharomyces cerevisiae is the main yeast used for alcohol production worldwide, but it cannot produce ethanol from xylose, the second most abundant sugar in nature. In general, naturally xylose-fermenting yeasts are capable of fermenting xylose only when the oxygen flow is tightly regulated. Because fermentative conditions such as media composition, cell density and oxygen availability are usually different, a comparative assessment among xylose-consuming yeasts based on literature data becomes difficult. Thus, a systematic comparison of yeasts performance might help to elucidate important steps involved in xylose transport and metabolism.The aim of this work was to compare the performance of native pentose-consuming yeasts under oxygenlimited and anaerobic conditions. The biomass growth, substrate consumption and products accumulation ofScheffersomyces stipitis, Spathaspora passalidarum, Pachysolen tannophilus, Ogataea siamensis,Kluyveromyces marxianus, Meyerozyma guilliermondii, Yamadazyma sp., Candida sp., Naganishia sp. andRhodotorula sp., were evaluated in experiments containing xylose as sole carbon source.The performance of the yeasts was greatly influenced by oxygen availability. All the strains showed higherbiomass yields under oxygen limitation whereas the production of ethanol was variable according theconsidered. While Scheffersomyces stipitis and Spathaspora passalidarum exhibited the highest xyloseconsumption specific rate under oxygen limitation, Ogataea siamensis, Pachysolen tannophilus,Kluyveromyces marxianus, Meyerozyma guilliermondii, Yamadazyma sp. and Candida sp. showed anintermediate performance among the assessed yeasts.