Ogataea nonmethanolica f.a, sp. nov., a novel yeast species isolated from rotting wood in Brazil and Colombia.

Three yeast isolate candidates for a novel species were obtained from rotting wood samples collected in Brazil and Colombia. The Brazilian isolate differs from the Colombian isolates by one nucleotide substitution in each of the D1/D2 and small subunit (SSU) sequences. The internal transcribed spacer (ITS) and translation elongation factor 1-α gene sequences of the three isolates were identical. A phylogenetic analysis showed that this novel species belongs to the genus Ogataea. This novel species is phylogenetically related to Candida nanaspora and Candida nitratophila. The novel species differs from C. nanaspora by seven nucleotides and two indels, and by 17 nucleotides and four indels from C. nitratophila in the D1/D2 sequences. The ITS sequences of these three species differ by more than 30 nucleotides. Analyses of the sequences of the SSU and translation elongation factor 1-α gene also showed that these isolates represent a novel species of the genus Ogataea. Different from most Ogataea species, these isolates did not assimilate methanol as the sole carbon source. The name Ogataea nonmethanolica sp. nov. is proposed to accommodate these isolates. The holotype of Ogataea nonmethanolica is CBS 13485T. The MycoBank number is MB 851195.

Starmera foglemanii sp. nov. and Starmera ilhagrandensis sp. nov., two novel yeast species isolated from ephemeral plant substrates.

Four isolates of two novel ascosporogenous species belonging to the clade Starmera were obtained from cactus tissues and rotting wood in Brazil. Results of analyses of the sequences of the ITS and D1/D2 domains of the large subunit rRNA gene indicated that the two isolates of the cactophilic species are related to Starmera caribaea and Starmera pilosocereana, yeasts that are associated with cacti and require an organic source of sulfur for growth. We propose the novel species Starmera foglemanii sp. nov. (CBS 16113T; MycoBank number: MB 834400) to accommodate these isolates. The other two isolates are phylogenetically related to Candida dendrica, Candida laemsonensis and Candida berthetii, also in the Starmera clade. The novel species name Starmera ilhagrandensis sp. nov. (CBS 16316T; MycoBank number: MB 834402) is proposed for this species.

Production of ethanol and xylanolytic enzymes by yeasts inhabiting rotting wood isolated in sugarcane bagasse hydrolysate.

Yeasts associated with rotting wood from four Atlantic Rain forest sites in Brazil were investigated using a culture medium based on sugarcane bagasse hydrolysate. A total of 330 yeast strains were isolated. Pichia manshurica, Candida pseudolambica, and Wickerhamomyces sp. 3 were the most frequently isolated species. Fourteen novel species were obtained in this study. All isolates were tested for their ability to ferment d-xylose and to produce xylanases. In the fermentation assays using d-xylose (30 g L-1), the main ethanol producers were Scheffersomyces stipitis (14.08 g L-1), Scheffersomyces sp. (7.94 g L-1) and Spathaspora boniae (7.16 g L-1). Sc. stipitis showed the highest ethanol yield (0.42 g g-1) and the highest productivity (0.39 g L-1h-1). The fermentation results using hemicellulosic hydrolysate showed that Sc. stipitis was the best ethanol producer, achieving a yield of 0.32 g g-1, while Sp. boniae and Scheffersomyces sp. were excellent xylitol producers. The best xylanase-producing yeasts at 50 °C belonged to the species Su. xylanicola (0.487 U mg-1) and Saitozyma podzolica (0.384 U mg-1). The results showed that rotting wood collected from the Atlantic Rainforest is a valuable source of yeasts able to grow in sugarcane bagasse hydrolysate, including species with promising biotechnological properties.

Occurrence, antifungal susceptibility, and virulence factors of opportunistic yeasts isolated from Brazilian beaches.

BACKGROUND: Opportunistic pathogenic yeast species are frequently associated with water habitats that have pollution sources of human or animal origin. Candida albicans has already been suggested as a faecal indicator microorganism for aquatic environments. OBJECTIVES: The goal of this study was to investigate the occurrence of C. albicans and other opportunistic yeasts in sand and seawater samples from beaches in Brazil to assess their correlation with Escherichia coli, and to characterise the pathogenic potential of the yeast isolates. METHODS: Opportunistic species (yeasts that grow at 37ºC) were isolated from sand and seawater samples from eight beaches in Brazil during the summer and the winter. Opportunistic yeast species were evaluated for their susceptibility to antifungal drugs, virulence factors, and the in vitro and in vivo biofilm formation. Strains were selected to carry out virulence tests using BALB/c mice. FINDINGS: Several water samples could be classified as inappropriate for primary contact recreation in relation to E. coli densities. C. albicans was isolated in low densities. Of the 144 opportunistic yeasts evaluated, 61% displayed resistance or dose-dependent sensitivity to at least one tested drug, and 40% produced proteinase. Strains of C. albicans and Kodamaea ohmeri exhibited the highest rates of adhesion to buccal epithelial cells. All the C. albicans strains that were tested were able to undergo morphogenesis and form a biofilm on catheter fragments in both in vitro and in vivo experiments. It was possible to confirm the pathogenic potential of three of these strains during the disseminated infection test. MAIN CONCLUSIONS: The identification of opportunistic yeast species in seawater and sand samples from Brazilian beaches suggest a potential risk to the health of people who use these environments for recreational purposes.

Occurrence, antifungal susceptibility, and virulence factors of opportunistic yeasts isolated from Brazilian beaches

BACKGROUND Opportunistic pathogenic yeast species are frequently associated with water habitats that have pollution sources of human or animal origin. Candida albicans has already been suggested as a faecal indicator microorganism for aquatic environments. OBJECTIVES The goal of this study was to investigate the occurrence of C. albicans and other opportunistic yeasts in sand and seawater samples from beaches in Brazil to assess their correlation with Escherichia coli, and to characterise the pathogenic potential of the yeast isolates. METHODS Opportunistic species (yeasts that grow at 37ºC) were isolated from sand and seawater samples from eight beaches in Brazil during the summer and the winter. Opportunistic yeast species were evaluated for their susceptibility to antifungal drugs, virulence factors, and the in vitro and in vivo biofilm formation. Strains were selected to carry out virulence tests using BALB/c mice. FINDINGS Several water samples could be classified as inappropriate for primary contact recreation in relation to E. coli densities. C. albicans was isolated in low densities. Of the 144 opportunistic yeasts evaluated, 61% displayed resistance or dose-dependent sensitivity to at least one tested drug, and 40% produced proteinase. Strains of C. albicans and Kodamaea ohmeri exhibited the highest rates of adhesion to buccal epithelial cells. All the C. albicans strains that were tested were able to undergo morphogenesis and form a biofilm on catheter fragments in both in vitro and in vivo experiments. It was possible to confirm the pathogenic potential of three of these strains during the disseminated infection test. MAIN CONCLUSIONS The identification of opportunistic yeast species in seawater and sand samples from Brazilian beaches suggest a potential risk to the health of people who use these environments for recreational purposes.

Spathaspora boniae sp. nov., a D-xylose-fermenting species in the Candida albicans/Lodderomyces clade.

Two yeast isolates producing asci-containing elongate ascospores with curved ends typical of the genus Spathaspora were isolated from rotting wood samples collected in an Atlantic rainforest ecosystem in Brazil. Phylogenetic analysis of the LSU rRNA gene D1/D2 domain sequences demonstrated that the strains represent a new species and placed it next to Candida blackwellae, in a clade that also contains Candida albicans and Candida dubliniensis. Other sequences of the ribosomal gene cluster supported same placementin the same clade, and a phylogenomic analysis placed this new species in an early emerging position relative to the larger C. albicans/Lodderomyces clade. One interpretation is that the genus Spathaspora is, in fact, paraphyletic. In conformity with this view, we propose the novel species Spathaspora boniae sp. nov. to accommodate the isolates. The type strain of Spathaspora boniae sp. nov. is UFMG-CM-Y306T (=CBS 13262T). The MycoBank number is MB 821297. A detailed analysis of xylose metabolism was conducted for the new species.

Draft genome sequence of Sugiyamaella xylanicola UFMG-CM-Y1884T, a xylan-degrading yeast species isolated from rotting wood samples in Brazil.

We present the draft genome sequence of the type strain of the yeast Sugiyamaella xylanicola UFMG-CM-Y1884T (= UFMG-CA-32.1T = CBS 12683T), a xylan-degrading species capable of fermenting d-xylose to ethanol. The assembled genome has a size of ~ 13.7 Mb and a GC content of 33.8% and contains 5971 protein-coding genes. We identified 15 genes with significant similarity to the d-xylose reductase gene from several other fungal species. The draft genome assembled from whole-genome shotgun sequencing of the yeast Sugiyamaella xylanicola UFMG-CM-Y1884T (= UFMG-CA-32.1T = CBS 12683T) has been deposited at DDBJ/ENA/GenBank under the accession number MQSX00000000 under version MQSX01000000.

D-Xylose fermentation, xylitol production and xylanase activities by seven new species of Sugiyamaella.

Sixteen yeast isolates identified as belonging to the genus Sugiyamaella were studied in relation to D-xylose fermentation, xylitol production, and xylanase activities. The yeasts were recovered from rotting wood and sugarcane bagasse samples in different Brazilian regions. Sequence analyses of the internal transcribed spacer (ITS) region and the D1/D2 domains of large subunit rRNA gene showed that these isolates belong to seven new species. The species are described here as Sugiyamaella ayubii f.a., sp. nov. (UFMG-CM-Y607T = CBS 14108T), Sugiyamaella bahiana f.a., sp. nov. (UFMG-CM-Y304T = CBS 13474T), Sugiyamaella bonitensis f.a., sp. nov. (UFMG-CM-Y608T = CBS 14270T), Sugiyamaella carassensis f.a., sp. nov. (UFMG-CM-Y606T = CBS 14107T), Sugiyamaella ligni f.a., sp. nov. (UFMG-CM-Y295T = CBS 13482T), Sugiyamaella valenteae f.a., sp. nov. (UFMG-CM-Y609T = CBS 14109T) and Sugiyamaella xylolytica f.a., sp. nov. (UFMG-CM-Y348T = CBS 13493T). Strains of the described species S. boreocaroliniensis, S. lignohabitans, S. novakii and S. xylanicola, isolated from rotting wood of Brazilian ecosystems, were also compared for traits relevant to xylose metabolism. S. valenteae sp. nov., S. xylolytica sp. nov., S. bahiana sp. nov., S. bonitensis sp. nov., S. boreocarolinensis, S. lignohabitans and S. xylanicola were able to ferment D-xylose to ethanol. Xylitol production was observed for all Sugiyamaella species studied, except for S. ayubii sp. nov. All species studied showed xylanolytic activity, with S. xylanicola, S. lignohabitans and S. valenteae sp. nov. having the highest values. Our results suggest these Sugiyamaella species have good potential for biotechnological applications.

Three novel ascomycetous yeast species of the Kazachstania clade, Kazachstania saulgeensis sp. nov., Kazachstaniaserrabonitensis sp. nov. and Kazachstania australis sp. nov. Reassignment of Candida humilis to Kazachstania humilis f.a. comb. nov. and Candida pseudohumilis to Kazachstania pseudohumilis f.a. comb. nov.

Five ascosporogenous yeast strains related to the genus Kazachstania were isolated. Two strains (CLIB 1764T and CLIB 1780) were isolated from French sourdoughs; three others (UFMG-CM-Y273T, UFMG-CM-Y451 and UFMG-CM-Y452) were from rotting wood in Brazil. The sequences of the French and Brazilian strains differed by one and three substitutions, respectively, in the D1/D2 large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS). The D1/D2 LSU rRNA sequence of these strains differed by 0.5 and 0.7 % from Kazachstania exigua, but their ITS sequences diverged by 8.1 and 8.3 %, respectively, from that of the closest described species Kazachstania barnettii. Analysis of protein coding sequences of RPB1, RPB2 and EF-1α distinguished the French from the Brazilian strains, with respectively 3.3, 6 and 11.7 % substitutions. Two novel species are described to accommodate these newly isolated strains: Kazachstania saulgeensis sp. nov. (type strain CLIB 1764T=CBS 14374T) and Kazachstania serrabonitensis sp. nov. (type strain UFMG-CM-Y273T=CLIB 1783T=CBS 14236T). Further analysis of culture collections revealed a strain previously assigned to the K. exigua species, but having 3.8 % difference (22 substitutions and 2 indels) in its ITS with respect to K. exigua. Hence, we describe a new taxon, Kazachstania australis sp. nov. (type strain CLIB 162T=CBS 2141T), to accommodate this strain. Finally, Candida humilis and Candida pseudohumilis are reassigned to the genus Kazachstania as new combinations. On the basis of sequence analysis, we also propose that Candida milleri and Kazachstania humilis comb. nov. are conspecific.

Saturnispora bothae sp. nov., isolated from rotting wood.

Two strains representing a novel species of the genus Saturnispora were isolated from rotting wood samples collected in an Atlantic Rainforest site in Brazil. Analyses of the sequences of the D1/D2 domains of the rRNA gene showed that this novel species belongs to a subclade in the Saturnispora clade formed by Saturnispora sanitii, Saturnispora sekii, Saturnispora silvae and Saturnisporasuwanaritii. The novel species differed in D1/D2 sequences by 60 or more nucleotide substitutions from these species. The strains produced asci with one to four hemispherical ascospores. A novel species named Saturnispora bothae sp. nov. is proposed to accommodate these isolates. The type strain is UFMG-CM-Y292T (=CBS 13484T). The MycoBank number is MB 817127.

Genomic analysis and D-xylose fermentation of three novel Spathaspora species: Spathaspora girioi sp. nov., Spathaspora hagerdaliae f. a., sp. nov. and Spathaspora gorwiae f. a., sp. nov.

Three novel D-xylose-fermenting yeast species of Spathaspora clade were recovered from rotting wood in regions of the Atlantic Rainforest ecosystem in Brazil. Differentiation of new species was based on analyses of the gene encoding the D1/D2 sequences of large subunit of rRNA and on 642 conserved, single-copy, orthologous genes from genome sequence assemblies from the newly described species and 15 closely-related Debaryomycetaceae/Metschnikowiaceae species. Spathaspora girioi sp. nov. produced unconjugated asci with a single elongated ascospore with curved ends; ascospore formation was not observed for the other two species. The three novel species ferment D-xylose with different efficiencies. Spathaspora hagerdaliae sp. nov. and Sp. girioi sp. nov. showed xylose reductase (XR) activity strictly dependent on NADPH, whereas Sp. gorwiae sp. nov. had XR activity that used both NADH and NADPH as co-factors. The genes that encode enzymes involved in D-xylose metabolism (XR, xylitol dehydrogenase and xylulokinase) were also identified for these novel species. The type strains are Sp. girioi sp. nov. UFMG-CM-Y302(T) (=CBS 13476), Sp. hagerdaliae f.a., sp. nov. UFMG-CM-Y303(T) (=CBS 13475) and Sp. gorwiae f.a., sp. nov. UFMG-CM-Y312(T) (=CBS 13472).

Spencermartinsiella silvicola sp. nov., a yeast species isolated from rotting wood.

Three strains of a new xylanase-producing yeast species were isolated from rotting wood samples collected in the Atlantic Rain Forest of Brazil. The sequences of the internal transcribed spacer region and D1/D2 domains of the large subunit of the rRNA gene showed that this novel yeast species belongs to the genus Spencermartinsiella, and its closest relatives among recognized species are Spencermartinsiella europaea and Spencermartinsiella ligniputridi. A novel species, named Spencermartinsiella silvicola sp. nov., is proposed to accommodate these isolates. The type strain is UFMG-CM-Y274T ( = CBS 13490T). The MycoBank number is MB 813053. In addition, Candida cellulosicola is reassigned to the genus Spencermartinsiella as a new combination.

D-xylose-fermenting and xylanase-producing yeast species from rotting wood of two Atlantic Rainforest habitats in Brazil.

This study investigated the yeast species associated with rotting wood in Brazilian Atlantic Rainforest ecosystems focusing on the identification of D-xylose-fermenting and/or xylanase-producing species. A total of 321 yeast strains were isolated from rotting wood samples collected in two Atlantic Rainforest areas. These samples were cultured in yeast nitrogen base (YNB)-D-xylose or YNB-xylan media. Schwanniomyces polymorphus, Scheffersomyces queiroziae, Barnettozyma californica, and Candida (Ogataea) boidinii were the most frequently isolated yeasts. The rarefaction curves for the yeast communities isolated in YNB-D-xylose and YNB-xylan from both areas continued to rise and did not reach an asymptote, indicating that not all yeast diversity had been recovered. Additionally, the yeast composition was variable among the samples and areas, which was confirmed by the values of the Sorensen index. Among the 69 species identified, only 12 were found in both areas sampled. Fifteen possible new species were obtained. Among them, two species (Sugiyamaella sp. 1 and Sugiyamaella xylanicola) showed the ability to ferment D-xylose into ethanol, and three species (Spencermartinsiella sp. 1, Su. xylanicola and Tremella sp.) were able to produce extracellular xylanases. Indeed, most of the xylanase-producing isolates belong to the new species Su. xylanicola, which was also positive for D-xylose fermentation. S.queiroziae and S. stipitis were the main D-xylose-fermenting yeasts identified. The results of this work showed that rotting wood collected from the Atlantic Rainforests is a huge source of yeasts, including new species, with promising biotechnological properties.

Sugiyamaella xylanicola sp. nov., a xylan-degrading yeast species isolated from rotting wood.

Four strains of a novel yeast species were isolated from rotting-wood samples in an Atlantic rainforest site in the state of Minas Gerais, Brazil. These yeasts were obtained from enrichments using yeast nitrogen base (YNB)-d-xylose or YNB-xylan media. The novel yeast species produces bacilliform ascospores typical of the genus Sugiyamaella, and its closest described relative in terms of sequence similarity is Candida (iter. nom. Sugiyamaella) marionensis. The yeast is able to grow in medium with xylan as sole carbon source and produces extracellular enzymes with xylanolytic activities. The novel species Sugiyamaella xylanicola sp. nov. is proposed to accommodate these isolates. The type strain is UFMG-CA-32.1(T) (=CBS 12683(T) =CBMAI 1467(T)).

Wickerhamiella pagnoccae sp. nov. and Candida tocantinsensis sp. nov., two ascomycetous yeasts from flower bracts of Heliconia psittacorum (Heliconiaceae).

Two novel yeast species were isolated from nectar of flower bracts of Heliconia psittacorum (Heliconiaceae) collected in a Cerrado ecosystem in the state of Tocantins, northern Brazil. Wickerhamiella pagnoccae sp. nov., which is closely related to Candida jalapaonensis, is heterothallic and produces one spheroid ascospore per ascus. Candida tocantinsensis sp. nov. belongs to the Metschnikowiaceae clade and its nearest relative is Candida ubatubensis, but the sequence identity (%) in the D1/D2 domains of the rRNA gene is low. The type strain of W. pagnoccae is UFMG-F18C1(T) ( = CBS 12178(T) = NRRL Y-48735(T)) and the type strain of C. tocantinsensis is UFMG-F16D1(T) ( = CBS 12177(T) = NRRL Y-48734(T)).