• Mycobiology
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• v.48 no.4
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• pp.296-303
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• 2020

Three yeast strains (Hue-1, Hue-8, and Hue-19) with strong heavy metal tolerance were isolated from mangosteen from Hue city, Vietnam. They exhibited identical phenotype and phylogeny. Sequence analysis of the D1/D2 region of the LSU rRNA gene and the internal transcribed spacer (ITS) region demonstrated that the closest relative of these strains is Papiliotrema sp. with 2.12% and 3.55-3.7% divergence in the D1/D2 domain, and ITS domain, respectively. Based on the physiological, biochemical, and molecular data, the three strains belong to a novel species of Papiliotrema genus, for which the name Papiliotrema huenov sp. nov. is proposed. These strains are highly tolerant of heavy metals compared to other yeasts, being able to grow in the presence of 2 mM Pb (II), 2 mM Cd (II), and up to 5 mM Ni (II), but no growth was observed in the presence of 1 mM As (III).

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.241-248
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• 2015

Tuak is a traditional alcoholic beverage, one of the most widely known in the North Sumateran region of Indonesia. It is produced by a spontaneous fermentation process through the application of one or more several kinds of wood bark or root, called raru (Xylocorpus wood bark or a variety of forest mangosteen), into the sap water of sugar palm (Arenga pinnata) for 2−3 days. In this research, yeast that are potentially useful for ethanol production was isolated from Tuak and identified. Based on analysis of D1/D2 domain sequence of LSU (large subunit) rRNA genes, those isolated yeast strains, HT4, HT5, and HT10 were identified as Candida tropicalis. Fermentation test of these C. tropicalis isolates displayed an ability to produce 6.55% (v/v) and 4.58% ethanol at 30℃ and 42℃, respectively. These results indicated C. tropicalis isolates more rapidly utilize glucose and obtain higher levels of the production of ethanol at the higher temperature of 42℃ than S. cerevisiae, a common yeast used for bioethanol fermentation.