RESUMEN
Six yeast isolates were obtained from rotting wood samples in Brazil and frass of a cerambycid beetle larva in French Guiana. Sequence analysis of the ITS-5.8S region and the D1/D2 domains of the large subunit rRNA gene showed that the isolates represent a novel species of Cyberlindnera. This novel species is related to Cyberlindnera japonica, Cyberlindnera xylosilytica, Candida easanensis and Candida maesa. It is heterothallic and produces asci with two or four hat-shaped ascospores. The name Cyberlindnera dasilvae sp. nov. is proposed to accommodate the novel species. The holotype of Cy. dasilvae is CBS 16129T and the designated paratype is CBS 16584. The MycoBank number is 838252. All isolates of Cy. dasilvae were able to convert xylose into xylitol with maximum xylitol production within 60 and 72 h. The isolates produced xylitol with values ranging from 12.61 to 31.79 g l-1 in yeast extract-peptone-xylose medium with 5% xylose. When the isolates were tested in sugarcane bagasse hydrolysate containing around 35-38 g l-1d-xylose, isolate UFMG-CM-Y519 showed maximum xylitol production.
Asunto(s)
Escarabajos/microbiología , Filogenia , Saccharomycetales/clasificación , Madera , Xilitol , Animales , ADN de Hongos/genética , ADN Espaciador Ribosómico , Heces/microbiología , Larva/microbiología , Técnicas de Tipificación Micológica , Saccharomycetales/aislamiento & purificación , Análisis de Secuencia de ADN , Madera/microbiología , Xilitol/metabolismoRESUMEN
Six strains of a novel yeast species were isolated from tree bark collected in the Atlantic Forest and the Amazon Rainforest in Brazil. Analyses of the sequences of D1/D2 domains of the large subunit rRNA gene showed that the strains belong to a species in the genus Zygotorulaspora. The species differed by 5.54â% sequence divergence (25 substitutions and five indels out of 542 bp) in the D1/D2 sequences from Zygotorulaspora mrakii, its closest relative. The ITS sequence of the type strain of the novel species differs by 27-69 nucleotide substitutions/indels from the other Zygotorulaspora species. The novel species is able to grow on trehalose, maltose, l-sorbose, inulin and at 37 °C, which are negative in Z. mrakii. The name Zygotorulaspora cariocana sp. nov. is proposed. The holotype of Z. cariocana sp. nov. is CBS 16118T. The MycoBank number is MB 833702.
Asunto(s)
Filogenia , Corteza de la Planta/microbiología , Saccharomycetales/clasificación , Brasil , ADN de Hongos/genética , ADN Espaciador Ribosómico/genética , Técnicas de Tipificación Micológica , Bosque Lluvioso , Saccharomycetales/aislamiento & purificación , Análisis de Secuencia de ADN , Árboles/microbiologíaRESUMEN
Yeasts of the Spathaspora clade have the ability to convert d-xylose to ethanol and/or xylitol. This is an important trait, as these yeasts may be used to produce bioethanol from lignocellulosic biomass or as a source of new d-xylose metabolism genes for recombinant industrial strains of Saccharomyces cerevisiae. The core group of the genus Spathaspora has 22 species, both formally described and not yet described. Other species, such as Sp. allomyrinae, Candida alai, C. insectamans, C. lyxosophila, C. sake, Sp. boniae and C. subhashii are weakly associated with this clade, based on LSU rRNA gene D1/D2 sequence analyses. Spathaspora passalidarum, Sp. arborariae, Sp. gorwiae and Sp. hagerdaliae produce mostly ethanol from d-xylose, whereas the remaining species within the Spathaspora clade already tested for this property may be considered xylitol producers. Among the d-xylose-fermenting Spathaspora species, Sp. passalidarum is the best ethanol producer, displaying high ethanol yields and productivities when cultured in media supplemented with this pentose under oxygen-limited or anaerobic conditions. The species also exhibits rapid d-xylose consumption and the ability to ferment glucose, xylose and cellobiose simultaneously. These characteristics suggest that Sp. passalidarum is a potential candidate for domestication and use in the fermentation of lignocellulosic materials. Copyright © 2017 John Wiley & Sons, Ltd.
Asunto(s)
Biocombustibles , Etanol/metabolismo , Levaduras/genética , Fermentación , Filogenia , Levaduras/clasificación , Levaduras/fisiologíaRESUMEN
Two strains of a novel yeast species were isolated from rotting wood of an ornamental tree (purple quaresmeira, Tibouchina granulosa, Melastomataceae) in an Atlantic Rainforest area in Brazil. Analysis of the sequences of the internal transcribed spacer (ITS-5.8S) region and the D1/D2 domains of the large subunit rRNA gene showed that this species belongs to the Spathaspora clade, and is phylogenetically related to Spathaspora brasiliensis, Candida materiae and Sp. girioi. The novel species ferments D-xylose, producing ethanol, with amounts between 3.37 and 3.48 g L-1 ethanol from 2% D-xylose. Ascospores were not observed from this new species. The name Spathaspora piracicabensis f. a., sp. nov. is proposed to accommodate these isolates. The type strain is UFMG-CM-Y5867T (= CBS 15054T = ESALQ-I54T). The MycoBank number is MB 822,320.
Asunto(s)
Filogenia , Saccharomycetales/clasificación , Madera/microbiología , Brasil , ADN Ribosómico/genética , ADN Espaciador Ribosómico/genética , Fermentación , Bosque Lluvioso , Saccharomycetales/metabolismo , Especificidad de la Especie , Xilosa/metabolismoRESUMEN
This study assessed the efficiency of Scheffersomyces amazonensis UFMG-CM-Y493T, cultured in xylose-supplemented medium (YPX) and rice hull hydrolysate (RHH), to convert xylose to xylitol under moderate and severe oxygen limitation. The highest xylitol yields of 0.75 and 1.04 g g-1 in YPX and RHH, respectively, were obtained under severe oxygen limitation. However, volumetric productivity in RHH was ninefold decrease than that in YPX medium. The xylose reductase (XR) and xylitol dehydrogenase (XDH) activities in the YPX cultures were strictly dependent on NADPH and NAD+ respectively, and were approximately 10% higher under severe oxygen limitation than under moderate oxygen limitation. This higher xylitol production observed under severe oxygen limitation can be attributed to the higher XR activity and shortage of the NAD+ needed by XDH. These results suggest that Sc. amazonensis UFMG-CM-Y493T is one of the greatest xylitol producers described to date and reveal its potential use in the biotechnological production of xylitol.
Asunto(s)
Debaryomyces/crecimiento & desarrollo , Xilitol/biosíntesis , Aldehído Reductasa/metabolismo , Medios de Cultivo/química , D-Xilulosa Reductasa/metabolismo , Debaryomyces/clasificación , Debaryomyces/enzimología , Fermentación , Proteínas Fúngicas/metabolismo , Microbiología Industrial , NAD/metabolismo , NADP/metabolismo , Xilitol/metabolismo , Xilosa/metabolismoRESUMEN
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.
Asunto(s)
Filogenia , Saccharomycetales/clasificación , Madera/microbiología , Brasil , ADN de Hongos/genética , Genes de ARNr , Técnicas de Tipificación Micológica , Bosque Lluvioso , Saccharomycetales/genética , Saccharomycetales/aislamiento & purificación , Análisis de Secuencia de ADNRESUMEN
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).
Asunto(s)
Fermentación , Genoma Fúngico , Genómica , Saccharomycetales/clasificación , Saccharomycetales/metabolismo , Xilosa/metabolismo , Brasil , Análisis por Conglomerados , Coenzimas/metabolismo , ADN de Hongos/química , ADN de Hongos/genética , ADN Ribosómico/química , ADN Ribosómico/genética , NAD/metabolismo , NADP/metabolismo , Filogenia , ARN Ribosómico/genética , Saccharomycetales/genética , Saccharomycetales/aislamiento & purificación , Análisis de Secuencia de ADN , Esporas Fúngicas/citología , Madera/microbiologíaRESUMEN
This study evaluated D-xylose-assimilating yeasts that are associated with rotting wood from the Galápagos Archipelago, Ecuador, for xylitol production from hemicellulose hydrolysates. A total of 140 yeast strains were isolated. Yeasts related to the clades Yamadazyma, Kazachstania, Kurtzmaniella, Lodderomyces, Metschnikowia and Saturnispora were predominant. In culture assays using sugarcane bagasse hemicellulose hydrolysate, Candida tropicalis CLQCA-24SC-125 showed the highest xylitol production, yield and productivity (27.1 g L(-1) xylitol, Y p/s (xyl) = 0.67 g g(-1), Qp = 0.38 g L(-1). A new species of Cyberlindnera, strain CLQCA-24SC-025, was responsible for the second highest xylitol production (24 g L(-1), Y p/s (xyl) = 0.64 g g(-1), Qp = 0.33 g L(-1) h(-1)) on sugarcane hydrolysate. The new xylitol-producing species Cyberlindnera galapagoensis f.a., sp. nov., is proposed to accommodate the strain CLQCA-24SC-025(T) (=UFMG-CM-Y517(T); CBS 13997(T)). The MycoBank number is MB 812171.
Asunto(s)
Madera/metabolismo , Madera/microbiología , Xilitol/metabolismo , Levaduras/clasificación , Levaduras/metabolismo , Análisis por Conglomerados , ADN de Hongos/química , ADN de Hongos/genética , Ecuador , Microscopía , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADN , Levaduras/genética , Levaduras/aislamiento & purificaciónRESUMEN
Independent surveys of yeasts associated with lignocellulosic-related materials led to the discovery of a novel yeast species belonging to the Cyberlindnera clade (Saccharomycotina, Ascomycota). Analysis of the sequences of the internal transcribed spacer (ITS) region and the D1/D2 domains of the large subunit rRNA gene showed that this species is related to C. japonica, C. maesa and C. easanensis. Six isolates were obtained from different sources, including rotting wood, tree bark and sugar cane filter cake in Brazil, frass from white oak in the USA and decayed leaf in Taiwan. A novel species is suggested to accommodate these isolates, for which the name C. xylosilytica sp. nov. is proposed. The type strain of C. xylosilytica sp. nov. is NRRL YB-2097(T) ( = CBS 13984(T) = UFMG-CM-Y347(T)) and the allotype is UFMG-CM-Y409 ( = CBS 14083). The novel species is heterothallic and complementary mating types are represented by the type and allotype strains. The MycoBank number is MB 811428.
Asunto(s)
Filogenia , Saccharomycetales/clasificación , Xilitol/metabolismo , Secuencia de Bases , Brasil , ADN de Hongos/genética , ADN Espaciador Ribosómico/genética , Datos de Secuencia Molecular , Corteza de la Planta/microbiología , Hojas de la Planta/microbiología , Quercus/microbiología , ARN Ribosómico/genética , ARN Ribosómico 16S/genética , Saccharomycetales/genética , Saccharomycetales/aislamiento & purificación , Saccharum/microbiología , Análisis de Secuencia de ADN , Taiwán , Madera/microbiologíaRESUMEN
In this study, yeasts associated with lignocellulosic materials in Brazil, including decaying wood and sugarcane bagasse, were isolated, and their ability to produce xylanolytic enzymes was investigated. A total of 358 yeast isolates were obtained, with 198 strains isolated from decaying wood and 160 strains isolated from decaying sugarcane bagasse samples. Seventy-five isolates possessed xylanase activity in solid medium and were identified as belonging to nine species: Candida intermedia, C. tropicalis, Meyerozyma guilliermondii, Scheffersomyces shehatae, Sugiyamaella smithiae, Cryptococcus diffluens, Cr. heveanensis, Cr. laurentii and Trichosporon mycotoxinivorans. Twenty-one isolates were further screened for total xylanase activity in liquid medium with xylan, and five xylanolytic yeasts were selected for further characterization, which included quantitative analysis of growth in xylan and xylose and xylanase and ß-D-xylosidase activities. The yeasts showing the highest growth rate and cell density in xylan, Cr. laurentii UFMG-HB-48, Su. smithiae UFMG-HM-80.1 and Sc. shehatae UFMG-HM-9.1a, were, simultaneously, those exhibiting higher xylanase activity. Xylan induced the highest level of (extracellular) xylanase activity in Cr. laurentii UFMG-HB-48 and the highest level of (intracellular, extracellular and membrane-associated) ß-D-xylosidase activity in Su. smithiae UFMG-HM-80.1. Also, significant ß-D-xylosidase levels were detected in xylan-induced cultures of Cr. laurentii UFMG-HB-48 and Sc. shehatae UFMG-HM-9.1a, mainly in extracellular and intracellular spaces, respectively. Under xylose induction, Cr. laurentii UFMG-HB-48 showed the highest intracellular ß-D-xylosidase activity among all the yeast tested. C. tropicalis UFMG-HB 93a showed its higher (intracellular) ß-D-xylosidase activity under xylose induction and higher at 30 °C than at 50 °C. This study revealed different xylanolytic abilities and strategies in yeasts to metabolise xylan and/or its hydrolysis products (xylo-oligosaccharides and xylose). Xylanolytic yeasts are able to secrete xylanolytic enzymes mainly when induced by xylan and present different strategies (intra- and/or extracellular hydrolysis) for the metabolism of xylo-oligosaccharides. Some of the unique xylanolytic traits identified here should be further explored for their applicability in specific biotechnological processes.
Asunto(s)
Biodiversidad , Saccharum/microbiología , Madera/microbiología , Xilanos/metabolismo , Xilosidasas/metabolismo , Levaduras/enzimología , Levaduras/crecimiento & desarrollo , Brasil , Celulosa , Medios de Cultivo/química , Hidrólisis , Temperatura , Levaduras/clasificación , Levaduras/aislamiento & purificaciónRESUMEN
The draft genome sequence of the yeast Spathaspora arborariae UFMG-HM19.1A(T) (CBS 11463 = NRRL Y-48658) is presented here. The sequenced genome size is 12.7 Mb, consisting of 41 scaffolds containing a total of 5,625 predicted open reading frames, including many genes encoding enzymes and transporters involved in d-xylose fermentation.
RESUMEN
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.
Asunto(s)
Madera/metabolismo , Xilosa/metabolismo , Xilosidasas/biosíntesis , Levaduras/clasificación , Levaduras/metabolismo , Biodiversidad , Brasil , ADN de Hongos/genética , Ecosistema , Etanol/metabolismo , Fermentación , Microbiota , Filogenia , Árboles/microbiología , Madera/microbiología , Levaduras/genética , Levaduras/aislamiento & purificaciónRESUMEN
Four new D-xylose fermenting yeast species of the clade Spathaspora were recovered from rotting-wood samples in a region of Amazonian forest, Northern Brazil. Three species produced unconjugated asci with a single elongated ascospore with curved ends. These species are described as Spathaspora brasiliensis, Spathaspora suhii and Spathaspora roraimanensis. Two isolates of an asexually reproducing species belonging to the Spathaspora clade were also obtained and they are described as Spathaspora xylofermentans. All these species are able to ferment D-xylose during aerobic batch growth in rich YP (1 % yeast extract, 2 % peptone and 2 % D-xylose) medium, albeit with differing efficiencies. The type strains are Spathaspora brasiliensis sp. nov UFMG-HMD19.3 (=CBMAI 1425=CBS 12679), Spathaspora suhii sp. nov. UFMG-XMD16.2 (=CBMAI 1426=CBS 12680), Spathaspora roraimanensis sp. nov. UFMG-XMD23.2 (CBMAI 1427=CBS 12681) and Spathaspora xylofermentans sp. nov. UFMG-HMD23.3 (=CBMAI 1428=CBS 12682).
Asunto(s)
Saccharomycetales/clasificación , Saccharomycetales/metabolismo , Madera/microbiología , Xilosa/metabolismo , Aerobiosis , Brasil , Análisis por Conglomerados , Medios de Cultivo/química , ADN de Hongos/química , ADN de Hongos/genética , ADN Ribosómico/química , ADN Ribosómico/genética , ADN Espaciador Ribosómico/química , ADN Espaciador Ribosómico/genética , Genes de ARNr , Microscopía , Filogenia , ARN de Hongos/genética , ARN Ribosómico/genética , Saccharomycetales/citología , Saccharomycetales/aislamiento & purificación , Análisis de Secuencia de ADN , ÁrbolesRESUMEN
BACKGROUND: This study is the first to investigate the Brazilian Amazonian Forest to identify new D-xylose-fermenting yeasts that might potentially be used in the production of ethanol from sugarcane bagasse hemicellulosic hydrolysates. METHODOLOGY/PRINCIPAL FINDINGS: A total of 224 yeast strains were isolated from rotting wood samples collected in two Amazonian forest reserve sites. These samples were cultured in yeast nitrogen base (YNB)-D-xylose or YNB-xylan media. Candida tropicalis, Asterotremella humicola, Candida boidinii and Debaryomyces hansenii were the most frequently isolated yeasts. Among D-xylose-fermenting yeasts, six strains of Spathaspora passalidarum, two of Scheffersomyces stipitis, and representatives of five new species were identified. The new species included Candida amazonensis of the Scheffersomyces clade and Spathaspora sp. 1, Spathaspora sp. 2, Spathaspora sp. 3, and Candida sp. 1 of the Spathaspora clade. In fermentation assays using D-xylose (50 g/L) culture medium, S. passalidarum strains showed the highest ethanol yields (0.31 g/g to 0.37 g/g) and productivities (0.62 g/L · h to 0.75 g/L · h). Candida amazonensis exhibited a virtually complete D-xylose consumption and the highest xylitol yields (0.55 g/g to 0.59 g/g), with concentrations up to 25.2 g/L. The new Spathaspora species produced ethanol and/or xylitol in different concentrations as the main fermentation products. In sugarcane bagasse hemicellulosic fermentation assays, S. stipitis UFMG-XMD-15.2 generated the highest ethanol yield (0.34 g/g) and productivity (0.2 g/L · h), while the new species Spathaspora sp. 1 UFMG-XMD-16.2 and Spathaspora sp. 2 UFMG-XMD-23.2 were very good xylitol producers. CONCLUSIONS/SIGNIFICANCE: This study demonstrates the promise of using new D-xylose-fermenting yeast strains from the Brazilian Amazonian Forest for ethanol or xylitol production from sugarcane bagasse hemicellulosic hydrolysates.
Asunto(s)
Variación Genética , Árboles/microbiología , Xilosa/metabolismo , Levaduras/genética , Levaduras/metabolismo , Brasil , Celulosa/metabolismo , Cartilla de ADN/genética , Etanol/metabolismo , Fermentación , Reacción en Cadena de la Polimerasa , Especificidad de la Especie , Xilitol/biosíntesisRESUMEN
Five strains of a novel yeast species were isolated from rotting wood samples collected in an Amazonian forest site in the state of Roraima, northern Brazil. The sequences of the D1/D2 domains of the large subunit of the rRNA gene showed that this species belongs to the Scheffersomyces clade and is related to Candida coipomoensis, Candida lignicola and Candida queiroziae. The novel species Candida amazonensis sp. nov. is proposed to accommodate these isolates. The type strain of C. amazonensis sp. nov. is UFMG-HMD-26.3(T) ( = CBS 12363(T) = NRRL Y-48762(T)).
Asunto(s)
Candida/clasificación , Candida/aislamiento & purificación , Árboles/microbiología , Madera/microbiología , Brasil , Candida/genética , ADN de Hongos/genética , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genéticaRESUMEN
The ability of a recently isolated Scheffersomyces stipitis strain (UFMG-IMH 43.2) to produce ethanol from xylose was evaluated. For the assays, a hemicellulosic hydrolysate produced by dilute acid hydrolysis of sugarcane bagasse was used as the fermentation medium. Initially, the necessity of adding nutrients (MgSO(4)·7H(2)O, yeast extract and/or urea) to this medium was verified, and the yeast extract supplementation favoured ethanol production by the yeast. Then, in a second stage, assays under different initial xylose and cell concentrations, supplemented or not with yeast extract, were performed. All these three variables showed significant (p < 0.05) influence on ethanol production. The best results (ethanol yield and productivity of 0.19 g/g and 0.13 g/l/h, respectively) were obtained using the hydrolysate containing an initial xylose concentration of 30 g/l, supplemented with 5.0 g/l yeast extract and inoculated with an initial cell concentration of 2.0 g/l. S. stipitis UFMG-IMH 43.2 was demonstrated to be a yeast strain with potential for use in xylose conversion to ethanol. The establishment of the best fermentation conditions was also proved to be of great importance to increasing the product formation by this yeast strain. These findings open up new perspectives for the establishment of a feasible technology for ethanol production from hemicellulosic hydrolysates.
Asunto(s)
Etanol/metabolismo , Saccharomycetales/metabolismo , Árboles/microbiología , Xilosa/metabolismo , Brasil , Fermentación , Saccharomycetales/genética , Saccharomycetales/aislamiento & purificaciónRESUMEN
Eight strains of a novel yeast species were isolated from rotting wood and wood-boring insects in Atlantic Rain Forest ecosystems in Brazil. Sequences of the D1/D2 domains of the large subunit of the rRNA gene showed that the yeast belongs to the Scheffersomyces clade and that it is related to Candida lignicola and Candida coipomoensis. The new species was isolated from rotting wood of three different localities and a wood-boring insect suggesting that these substrates are its ecological niche. This new yeast species is able to assimilate cellobiose and other compounds related to rotting wood. Strong fermentation of cellobiose in Durham tubes was observed for the strains of this new yeast. The new species produced an intracellular ß-glucosidase responsible for cellobiose hydrolysis. The novel species, Candida queiroziae sp. nov., is proposed to accommodate these isolates. The type strain of C. queiroziae is UFMG-CLM 5.1(T) (=CBS 11853(T) = NRRL Y-48722(T)).
Asunto(s)
Candida/aislamiento & purificación , Candida/metabolismo , Celobiosa/metabolismo , Árboles , Candida/enzimología , Fermentación , Análisis de Secuencia de ADN , beta-Glucosidasa/metabolismoRESUMEN
Four strains of a new yeast species were isolated from rotting wood from two sites in an Atlantic Rain Forest and a Cerrado ecosystem in Brazil. The analysis of the sequences of the D1/D2 domains of the large-subunit rRNA gene showed that this species belongs to the Spathaspora clade. The new species ferments D-xylose efficiently and is related to Candida jeffriesii and Spathaspora passalidarum, both of which also ferment D-xylose. Similar to S. passalidarum, the new species produces unconjugated asci with a single greatly elongated ascospore with curved ends. The type strain of Spathaspora arborariae sp. nov. is UFMG-HM19.1A(T) (=CBS11463(T)=NRRL Y-48658(T)).
Asunto(s)
Saccharomycetales/clasificación , Saccharomycetales/aislamiento & purificación , Madera/microbiología , Xilosa/metabolismo , Brasil , Candida/genética , Análisis por Conglomerados , ADN de Hongos/química , ADN de Hongos/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Genes de ARNr , Datos de Secuencia Molecular , Filogenia , ARN de Hongos/genética , ARN Ribosómico 28S/genética , Saccharomycetales/citología , Saccharomycetales/metabolismo , Análisis de Secuencia de ADN , Esporas Fúngicas/citologíaRESUMEN
Three strains of a novel yeast species, Candida materiae sp. nov., were isolated from rotting wood in an Atlantic rain forest site in Brazil. Analysis of the sequences of the D1/D2 domains of the large-subunit rDNA showed that this species belonged to the Spathaspora clade and was related to Candida jeffriesii and Spathaspora passalidarum. Unlike C. jeffriesii and S. passalidarum, C. materiae sp. nov. did not ferment xylose. The type strain of C. materiae sp. nov. is UFMG-07-C15.1BT (=CBS 10975T=CBMAI 956T).
Asunto(s)
Candida/clasificación , Candida/aislamiento & purificación , Madera/microbiología , Brasil , Candida/genética , Análisis por Conglomerados , ADN de Hongos/química , ADN de Hongos/genética , ADN Ribosómico/química , ADN Ribosómico/genética , ADN Espaciador Ribosómico/química , ADN Espaciador Ribosómico/genética , Genes de ARNr , Microscopía de Contraste de Fase , Datos de Secuencia Molecular , Filogenia , ARN de Hongos/genética , ARN Ribosómico/genética , Análisis de Secuencia de ADN , Árboles , Clima TropicalRESUMEN
The physiological and kinetic capabilities of 233 Saccharomyces cerevisiae isolates, originating from traditional Brazilian cachaça fermentation, were evaluated under laboratory conditions to select flocculent and non-H2S producing strains to be employed in beverage production. Three flocculent S. cerevisiae strains were selected, two non-H2S producing and one H2S producing, and their kinetic performances were analysed during two large-scale fermentation experiments in a traditional cachaça distillery. One non-flocculent H2S-producing S. cerevisiae strain was also used for comparison with the flocculent strains. The results of mitochondrial DNA restriction analysis showed that the three flocculent starter S. cerevisiae strains, as well as the non-flocculent strain, remained in the process during the whole fermentation period, with cells numbering around 10(7) cfu/ml. All selected strains produced ethanol yields that were typically higher in the distillery than in the laboratory conditions, except for strain UFMGA-1240. The greatest diversity of non-Saccharomyces yeasts was observed prior to day 21 of cachaça fermentation; Pichia membranifaciens and Hanseniaspora guilliermondii were the most frequently isolated species. These yeasts were present in lower densities throughout the whole process. The cachaça produced by the selected strains contained concentrations of chemical compounds in accordance with current Brazilian legislation, and all cachaças scored well in sensory effective tests. In addition to the advantage of being flocculent, the strain UFMGA-1031 is non-H2S producing and also produces cachaça with good sensory acceptance. Therefore, this flocculent and non-H2S producing S. cerevisiae strain is highly suitable as a starter for production of high quality traditional cachaça.