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

Yeasts from tropical forests: Biodiversity, ecological interactions, and as sources of bioinnovation

Tropical rainforests and related biomes are found in Asia, Australia, Africa, Central and South America, Mexico, and many Pacific Islands. These biomes encompass less than 20% of Earth's terrestrial area, may contain about 50% of the planet's biodiversity, and are endangered regions vulnerable to deforestation. Tropical rainforests have a great diversity of substrates that can be colonized by yeasts. These unicellular fungi contribute to the recycling of organic matter, may serve as a food source for other organisms, or have ecological interactions that benefit or harm plants, animals, and other fungi. In this review, we summarize the most important studies of yeast biodiversity carried out in these biomes, as well as new data, and discuss the ecology of yeast genera frequently isolated from tropical forests and the potential of these microorganisms as a source of bioinnovation. We show that tropical forest biomes represent a tremendous source of new yeast species. Although many studies, most using culture-dependent methods, have already been carried out in Central America, South America, and Asia, the tropical forest biomes of Africa and Australasia remain an underexplored source of novel yeasts. We hope that this review will encourage new researchers to study yeasts in unexplored tropical forest habitats.

The Brazilian Amazonian rainforest harbors a high diversity of yeasts associated with rotting wood, including many candidates for new yeast species

This study investigated the diversity of yeast species associated with rotting wood in Brazilian Amazonian rainforests. A total of 569 yeast strains were isolated from rotting wood samples collected in three Amazonian areas (Universidade Federal do Amazonas-Universidade Federal do Amazonas [UFAM], Piquiá, and Carú) in the municipality of Itacoatiara, Amazon state. The samples were cultured in yeast nitrogen base (YNB)-d-xylose, YNB-xylan, and sugarcane bagasse and corncob hemicellulosic hydrolysates (undiluted and diluted 1:2 and 1:5). Sugiyamaella was the most prevalent genus identified in this work, followed by Kazachstania. The most frequently isolated yeast species were Schwanniomyces polymorphus, Scheffersomyces amazonensis, and Wickerhamomyces sp., respectively. The alpha diversity analyses showed that the dryland forest of UFAM was the most diverse area, while the floodplain forest of Carú was the least. Additionally, the difference in diversity between UFAM and Carú was the highest among the comparisons. Thirty candidates for new yeast species were obtained, representing 36% of the species identified and totaling 101 isolates. Among them were species belonging to the clades Spathaspora, Scheffersomyces, and Sugiyamaella, which are recognized as genera with natural xylose-fermenting yeasts that are often studied for biotechnological and ecological purposes. The results of this work showed that rotting wood collected from the Amazonian rainforest is a tremendous source of diverse yeasts, including candidates for new species.

Uncovering the Yeast Communities in Fungus-Growing Ant Colonies

Yeast-insect interactions are compelling models to study the evolution, ecology, and diversification of yeasts. Fungus-growing (attine) ants are prominent insects in the Neotropics that evolved an ancient fungiculture of basidiomycete fungi over 55-65 million years, supplying an environment for a hidden yeast diversity. Here we assessed the yeast diversity in the attine ant environment by thoroughly sampling fungus gardens across four out of five ant fungiculture systems: Acromyrmex coronatus and Mycetomoellerius tucumanus standing for leaf-cutting and higher-attine fungicultures, respectively; Apterostigma sp., Mycetophylax sp., and Mycocepurus goeldii as ants from the lower-attine fungiculture. Among the fungus gardens of all fungus-growing ants examined, we found taxonomically unique and diverse microbial yeast communities across the different fungicultures. Ascomycete yeasts were the core taxa in fungus garden samples, with Saccharomycetales as the most frequent order. The genera Aureobasidium, Candida, Papiliotrema, Starmerella, and Sugiyamaella had the highest incidence in fungus gardens. Despite the expected similarity within the same fungiculture system, colonies of the same ant species differed in community structure. Among Saccharomycotina yeasts, few were distinguishable as killer yeasts, with a classical inhibition pattern for the killer phenotype, differing from earlier observations in this environment, which should be further investigated. Yeast mycobiome in fungus gardens is distinct between colonies of the same fungiculture and each ant colony harbors a distinguished and unique yeast community. Fungus gardens of attine ants are emergent environments to study the diversity and ecology of yeasts associated with insects.

Cellulolytic and Xylanolytic Enzymes from Yeasts: Properties and Industrial Applications

Lignocellulose, the main component of plant cell walls, comprises polyaromatic lignin and fermentable materials, cellulose and hemicellulose. It is a plentiful and renewable feedstock for chemicals and energy. It can serve as a raw material for the production of various value-added products, including cellulase and xylanase. Cellulase is essentially required in lignocellulose-based biorefineries and is applied in many commercial processes. Likewise, xylanases are industrially important enzymes applied in papermaking and in the manufacture of prebiotics and pharmaceuticals. Owing to the widespread application of these enzymes, many prokaryotes and eukaryotes have been exploited to produce cellulase and xylanases in good yields, yet yeasts have rarely been explored for their plant-cell-wall-degrading activities. This review is focused on summarizing reports about cellulolytic and xylanolytic yeasts, their properties, and their biotechnological applications.

Four new species of Trichomonascaceae (Saccharomycetales, Saccharomycetes) from Central China

Trichomonascaceae is the largest family of ascomycetous yeast in the order Saccharomycetales. In spite of the extensive body of research on Trichomonascaceae in China, there remain new species to be discovered. Here, we describe four new species isolated from several rotting wood samples from Henan Province, Central China. Phylogenetic analysis of a combined ITS and nrLSU dataset with morphological studies revealed four new species in the Trichomonascaceae: Diddensiellaluoyangensis, Sugiyamaellacylindrica, Su.robnettiae, and Zygoascusdetingensis. Clustering in the Diddensiella clade, D.luoyangensis' closest neighbour was D.transvaalensis. Meanwhile, Su.cylindrica clustered in the Sugiyamaella clade closest to Su.marilandica and Su.qingdaonensis. Also clustering in the Sugiyamaella clade, Su.robnettiae was most closely related to Su.chuxiongensis. Finally, Z.detingensis occupied a distinct and separated basal branch from the other species of the genus Zygoascus. These results indicate a high species diversity of Trichomonascaceae.

Yeast GH30 Xylanase from Sugiyamaella lignohabitans Is a Glucuronoxylanase with Auxiliary Xylobiohydrolase Activity

Xylanases are the enzymes that catalyze the breakdown of the main hemicellulose present in plant cell walls. They have attracted attention due to their biotechnological potential for the preparation of industrially interesting products from lignocellulose. While many xylanases have been characterized from bacteria and filamentous fungi, information on yeast xylanases is scarce and no yeast xylanase belonging to glycoside hydrolase (GH) family 30 has been described so far. Here, we cloned, expressed and characterized GH30 xylanase SlXyn30A from the yeast Sugiyamaella lignohabitans. The enzyme is active on glucuronoxylan (8.4 U/mg) and rhodymenan (linear β-1,4-1,3-xylan) (3.1 U/mg) while its activity on arabinoxylan is very low (0.03 U/mg). From glucuronoxylan SlXyn30A releases a series of acidic xylooligosaccharides of general formula MeGlcA²Xyl_n. These products, which are typical for GH30-specific glucuronoxylanases, are subsequently shortened at the non-reducing end, from which xylobiose moieties are liberated. Xylobiohydrolase activity was also observed during the hydrolysis of various xylooligosaccharides. SlXyn30A thus expands the group of glucuronoxylanases/xylobiohydrolases which has been hitherto represented only by several fungal GH30-7 members.

Extremophilic Prokaryotic Endoxylanases: Diversity, Applicability, and Molecular Insights

Extremophilic endoxylanases grabbed attention in recent years due to their applicability under harsh conditions of several industrial processes. Thermophilic, alkaliphilic, and acidophilic endoxylanases found their employability in bio-bleaching of paper pulp, bioconversion of lignocellulosic biomass into xylooligosaccharides, bioethanol production, and improving the nutritious value of bread and other bakery products. Xylanases obtained from extremophilic bacteria and archaea are considered better than fungal sources for several reasons. For example, enzymatic activity under broad pH and temperature range, low molecular weight, cellulase-free activity, and longer stability under extreme conditions of prokaryotic derived xylanases make them a good choice. In addition, a short life span, easy cultivation/harvesting methods, higher yield, and rapid DNA manipulations of bacterial and archaeal cells further reduces the overall cost of the product. This review focuses on the diversity of prokaryotic endoxylanases, their characteristics, and their functional attributes. Besides, the molecular mechanisms of their extreme behavior have also been presented here.

CAZyme prediction in ascomycetous yeast genomes guides discovery of novel xylanolytic species with diverse capacities for hemicellulose hydrolysis

BACKGROUND

Ascomycetous yeasts from the kingdom fungi inhabit every biome in nature. While filamentous fungi have been studied extensively regarding their enzymatic degradation of the complex polymers comprising lignocellulose, yeasts have been largely overlooked. As yeasts are key organisms used in industry, understanding their enzymatic strategies for biomass conversion is an important factor in developing new and more efficient cell factories. The aim of this study was to identify polysaccharide-degrading yeasts by mining CAZymes in 332 yeast genomes from the phylum Ascomycota. Selected CAZyme-rich yeasts were then characterized in more detail through growth and enzymatic activity assays.

RESULTS

The CAZyme analysis revealed a large spread in the number of CAZyme-encoding genes in the ascomycetous yeast genomes. We identified a total of 217 predicted CAZyme families, including several CAZymes likely involved in degradation of plant polysaccharides. Growth characterization of 40 CAZyme-rich yeasts revealed no cellulolytic yeasts, but several species from the Trichomonascaceae and CUG-Ser1 clades were able to grow on xylan, mixed-linkage β-glucan and xyloglucan. Blastobotrys mokoenaii, Sugiyamaella lignohabitans, Spencermartinsiella europaea and several Scheffersomyces species displayed superior growth on xylan and well as high enzymatic activities. These species possess genes for several putative xylanolytic enzymes, including ones from the well-studied xylanase-containing glycoside hydrolase families GH10 and GH30, which appear to be attached to the cell surface. B. mokoenaii was the only species containing a GH11 xylanase, which was shown to be secreted. Surprisingly, no known xylanases were predicted in the xylanolytic species Wickerhamomyces canadensis, suggesting that this yeast possesses novel xylanases. In addition, by examining non-sequenced yeasts closely related to the xylanolytic yeasts, we were able to identify novel species with high xylanolytic capacities.

CONCLUSIONS

Our approach of combining high-throughput bioinformatic CAZyme-prediction with growth and enzyme characterization proved to be a powerful pipeline for discovery of novel xylan-degrading yeasts and enzymes. The identified yeasts display diverse profiles in terms of growth, enzymatic activities and xylan substrate preferences, pointing towards different strategies for degradation and utilization of xylan. Together, the results provide novel insights into how yeast degrade xylan, which can be used to improve cell factory design and industrial bioconversion processes.

Kinetics Study of the Hydrodeoxygenation of Xylitol over a ReOx-Pd/CeO2 Catalyst

In this study, we elucidate the reaction kinetics for the simultaneous hydrodeoxygenation of xylitol to 1,2-dideoxypentitol and 1,2,5-pentanetriol over a ReOx-Pd/CeO2 (2.0 weight% Re, 0.30 weight% Pd) catalyst. The reaction was determined to be a zero-order reaction with respect to xylitol. The activation energy was elucidated through an Arrhenius relationship as well as non-Arrhenius kinetics. The Arrhenius relationship was investigated at 150–170 °C and a constant H2 pressure of 10 bar resulting in an activation energy of 48.7 ± 10.5 kJ/mol. The investigation of non-Arrhenius kinetics was conducted at 120–170 °C and a sub-Arrhenius relation was elucidated with activation energy being dependent on temperature, and ranging from 10.2–51.8 kJ/mol in the temperature range investigated. Internal and external mass transfer were investigated through evaluating the Weisz–Prater criterion and the effect of varying stirring rate on the reaction rate, respectively. There were no internal or external mass transfer limitations present in the reaction.

Diversity of the genus Sugiyamaella and description of two new species from rotting wood in China

Species of the genus Sugiyamaella (Trichomonascaceae, Saccharomycetales), found in rotting wood in China, were investigated using morphology and the molecular phylogeny of a combined ITS and nrLSU dataset. Nine taxa were collected in China: two were new species (viz. Sugiyamaellachuxiongsp. nov. and S.yunanensissp. nov.) and seven were known species, S.americana, S.ayubii, S.novakii, S.paludigena, S.valenteae, S.valdiviana and S.xiaguanensis. The two new species are illustrated and their morphology and phylogenetic relationships with other Sugiyamaella species are discussed. Our results indicate a potentially great diversity of Sugiyamaella spp. inhabiting rotting wood in China just waiting to be discovered.

Soil Yeast Communities in Revegetated Post-Mining and Adjacent Native Areas in Central Brazil

Yeasts represent an important component of the soil microbiome. In central Brazil, mining activities are among the main anthropogenic factors that influence the dynamics of the soil microbiota. Few studies have been dedicated to analysis of tropical soil yeast communities, and even fewer have focused on Brazilian hotspots influenced by mining activity. The aim of the current study was to describe soil yeast communities in a post-mining site with revegetated and native areas, along Neotropical Savanna and Atlantic Forest biomes. Yeast communities were described using a culture-based method and estimator-based species accumulation curves, and their associations with environmental characteristics were assessed using multivariate analysis. The results indicate a greater species richness for yeast communities in the revegetated area. We identified 37 species describing 86% of the estimated richness according to Chao2. Ascomycetous yeasts dominated over basidiomycetous species. Candida maltosa was the most frequent species in two phytocenoses. Red-pigmented yeasts were frequent only in the summer. The main soil attributes affecting yeast communities were texture and micronutrients. In conclusion, each phytocenosis showed a particular assemblage of species as a result of local environmental phenomena. The species richness in a Revegetated area points to a possible ecological role of yeast species in environmental recovery. This study provided the first comprehensive inventory of soil yeasts in major phytocenoses in Minas Gerais, Brazil.

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.

Mangrove soil as a source for novel xylanase and amylase as determined by cultivation-dependent and cultivation-independent methods

Xylanase and α-amylase enzymes participate in the degradation of organic matter, acting in hemicellulose and starch mineralization, respectively, and are in high demand for industrial use. Mangroves represent a promising source for bioprospecting enzymes due to their unique characteristics, such as fluctuations in oxic/anoxic conditions and salinity. In this context, the present work aimed to bioprospect xylanases from mangrove soil using cultivation-dependent and cultivation-independent methods. Through screening from a metagenomic library, three potentially xylanolytic clones were obtained and sequenced, and reads were assembled into contigs and annotated. The contig MgrBr135 was affiliated with the Planctomycetaceae family and was one of 30 ORFs selected for subcloning that demonstrated only amylase activity. Through the cultivation method, 38 bacterial isolates with xylanolytic activity were isolated. Isolate 11 showed an enzymatic index of 10.9 using the plate assay method. Isolate 39 achieved an enzyme activity of 0.43 U/mL using the colorimetric method with 3,5-dinitrosalicylic acid. Isolate 39 produced xylanase on culture medium with salinity ranging from 1.25 to 5%. Partial 16S rRNA gene sequencing identified isolates in the Bacillus and Paenibacillus genera. The results of this study highlight the importance of mangroves as an enzyme source and show that bacterial groups can be used for starch and hemicellulose degradation.

High-Level Heterologous Expression of Endo-1,4-β-Xylanase from Penicillium citrinum in Pichia pastoris X-33 Directed through Codon Optimization and Optimized Expression

Most common industrial xylanases are produced from filamentous fungi. In this study, the codon-optimized xynA gene encoding xylanase A from the fungus Penicilium citrinum was successfully synthesized and expressed in the yeast Pichia pastoris. The levels of secreted enzyme activity under the control of glyceraldehyde-3-phosphate dehydrogenase (P_GAP) and alcohol oxidase 1 (P_AOX1) promoters were compared. The Pc Xyn11A was produced as a soluble protein and the total xylanase activity under the control of P_GAP and P_AOX1 was 34- and 193-fold, respectively, higher than that produced by the native strain of P. citrinum. The Pc Xyn11A produced under the control of the P_AOX1 reached a maximum activity of 676 U/mL when induced with 1% (v/v) methanol every 24 h for 5 days. The xylanase was purified by ion exchange chromatography and then characterized. The enzyme was optimally active at 55 °C and pH 5.0 but stable over a broad pH range (3.0–9.0), retaining more than 80% of the original activity after 24 h or after pre-incubation at 40 °C for 1 h. With birchwood xylan as a substrate, Pc Xyn11A showed a K_m(app) of 2.8 mg/mL, and a k_cat of 243 s⁻¹. The high level of secretion of Pc Xyn11A and its stability over a wide range of pH and moderate temperatures could make it useful for a variety of biotechnological applications.

Fungal Planet description sheets: 868-950

Novel species of fungi described in this study include those from various countries as follows: Australia, Chaetomella pseudocircinoseta and Coniella pseudodiospyri on Eucalyptus microcorys leaves, Cladophialophora eucalypti, Teratosphaeria dunnii and Vermiculariopsiella dunnii on Eucalyptus dunnii leaves, Cylindrium grande and Hypsotheca eucalyptorum on Eucalyptus grandis leaves, Elsinoe salignae on Eucalyptus saligna leaves, Marasmius lebeliae on litter of regenerating subtropical rainforest, Phialoseptomonium eucalypti (incl. Phialoseptomonium gen. nov.) on Eucalyptus grandis × camaldulensis leaves, Phlogicylindrium pawpawense on Eucalyptus tereticornis leaves, Phyllosticta longicauda as an endophyte from healthy Eustrephus latifolius leaves, Pseudosydowia eucalyptorum on Eucalyptus sp. leaves, Saitozyma wallum on Banksia aemula leaves, Teratosphaeria henryi on Corymbia henryi leaves. Brazil, Aspergillus bezerrae, Backusella azygospora, Mariannaea terricola and Talaromyces pernambucoensis from soil, Calonectria matogrossensis on Eucalyptus urophylla leaves, Calvatia brasiliensis on soil, Carcinomyces nordestinensis on Bromelia antiacantha leaves, Dendryphiella stromaticola on small branches of an unidentified plant, Nigrospora brasiliensis on Nopalea cochenillifera leaves, Penicillium alagoense as a leaf endophyte on a Miconia sp., Podosordaria nigrobrunnea on dung, Spegazzinia bromeliacearum as a leaf endophyte on Tilandsia catimbauensis, Xylobolus brasiliensis on decaying wood. Bulgaria, Kazachstania molopis from the gut of the beetle Molops piceus. Croatia, Mollisia endocrystallina from a fallen decorticated Picea abies tree trunk. Ecuador, Hygrocybe rodomaculata on soil. Hungary, Alfoldia vorosii (incl. Alfoldia gen. nov.) from Juniperus communis roots, Kiskunsagia ubrizsyi (incl. Kiskunsagia gen. nov.) from Fumana procumbens roots. India, Aureobasidium tremulum as laboratory contaminant, Leucosporidium himalayensis and Naganishia indica from windblown dust on glaciers. Italy, Neodevriesia cycadicola on Cycas sp. leaves, Pseudocercospora pseudomyrticola on Myrtus communis leaves, Ramularia pistaciae on Pistacia lentiscus leaves, Neognomoniopsis quercina (incl. Neognomoniopsis gen. nov.) on Quercus ilex leaves. Japan, Diaporthe fructicola on Passiflora edulis × P. edulis f. flavicarpa fruit, Entoloma nipponicum on leaf litter in a mixed Cryptomeria japonica and Acer spp. forest. Macedonia, Astraeus macedonicus on soil. Malaysia, Fusicladium eucalyptigenum on Eucalyptus sp. twigs, Neoacrodontiella eucalypti (incl. Neoacrodontiella gen. nov.) on Eucalyptus urophylla leaves. Mozambique, Meliola gorongosensis on dead Philenoptera violacea leaflets. Nepal, Coniochaeta dendrobiicola from Dendriobium lognicornu roots. New Zealand, Neodevriesia sexualis and Thozetella neonivea on Archontophoenix cunninghamiana leaves. Norway, Calophoma sandfjordenica from a piece of board on a rocky shoreline, Clavaria parvispora on soil, Didymella finnmarkica from a piece of Pinus sylvestris driftwood. Poland, Sugiyamaella trypani from soil. Portugal, Colletotrichum feijoicola from Acca sellowiana. Russia, Crepidotus tobolensis on Populus tremula debris, Entoloma ekaterinae, Entoloma erhardii and Suillus gastroflavus on soil, Nakazawaea ambrosiae from the galleries of Ips typographus under the bark of Picea abies. Slovenia, Pluteus ludwigii on twigs of broadleaved trees. South Africa, Anungitiomyces stellenboschiensis (incl. Anungitiomyces gen. nov.) and Niesslia stellenboschiana on Eucalyptus sp. leaves, Beltraniella pseudoportoricensis on Podocarpus falcatus leaf litter, Corynespora encephalarti on Encephalartos sp. leaves, Cytospora pavettae on Pavetta revoluta leaves, Helminthosporium erythrinicola on Erythrina humeana leaves, Helminthosporium syzygii on a Syzygium sp. bark canker, Libertasomyces aloeticus on Aloe sp. leaves, Penicillium lunae from Musa sp. fruit, Phyllosticta lauridiae on Lauridia tetragona leaves, Pseudotruncatella bolusanthi (incl. Pseudotruncatellaceae fam. nov.) and Dactylella bolusanthi on Bolusanthus speciosus leaves. Spain, Apenidiella foetida on submerged plant debris, Inocybe grammatoides on Quercus ilex subsp. ilex forest humus, Ossicaulis salomii on soil, Phialemonium guarroi from soil. Thailand, Pantospora chromolaenae on Chromolaena odorata leaves. Ukraine, Cadophora helianthi from Helianthus annuus stems. USA, Boletus pseudopinophilus on soil under slash pine, Botryotrichum foricae, Penicillium americanum and Penicillium minnesotense from air. Vietnam, Lycoperdon vietnamense on soil. Morphological and culture characteristics are supported by DNA barcodes.

Large biodiversity of yeasts in French Guiana and the description of Suhomyces coccinellae f.a. sp. nov. and Suhomyces faveliae f.a. sp. nov

The extent of the diversity of yeasts in tropical rain forest and different environments from French Guiana was investigated. A total of 365 samples were collected from various substrates, such as plants, fruits and insects, at 13 locations, yielding 276 pure yeast isolates. Sequence analysis of the D1/D2 domains of the large subunit rRNA gene indicated that 210 isolates out of 276 belonged to 82 described species (67 Saccharomycotina, 14 Basidiomycota and 1 Pezizomycotina). In addition to these, a total of 54 Saccharomycotina isolates could not be assigned to a known species. These belonged to 14 genera and should be studied further from a taxonomic point of view. In addition, among the 43 Basidiomycotina isolates found, 12 could not be assigned to a known species. This report shows an unexpected biodiversity and indicates that oversea territories, such as French Guiana, constitute a largely unexplored reservoir for yeast diversity. Two Saccharomycotina strains, CLIB 1706 and CLIB 1725, isolated from an insect and from a fern respectively, were characterized further and were shown to belong to the Suhomyces clade on the basis of the rDNA sequence comparison. CLIB 1706^TrDNA sequences showed nine substitutions and three indels out of 556 bp (D1/D2 domains) and 32 substitutions and 12 indels out of 380 bp [internal transcribed spacer (ITS)] with that of the most closely related species Suhomyces guaymorum CBS 9823^T. CLIB 1725^T rDNA sequences presented 18 substitutions and one indel out of 549 bp (D1/D2 domains) and 48 substitutions and 11 indels out of 398 bp (ITS) with that of its closest relative Suhomyces vadensis CBS 9454^T. Two novel species of the genus Suhomyces were described to accommodate these two strains: Suhomyces coccinellae f.a. sp. nov. (CLIB 1706^T=CBS 14298^T) and Suhomyces faveliae f.a. sp. nov. (CLIB 1725^T=CBS 14299^T).

Sugiyamaella xiaguanensis f.a., sp. nov., a yeast species isolated from rotting wood

Three strains representing a novel yeast species, Sugiyamaella xiaguanensis f.a., sp. nov. (type strain NYNU 161041^T=CICC 33167^T=CBS 14696^T), were isolated from rotting wood samples collected in Henan and Yunnan Provinces, PR China. The novel species is able to assimilate cellobiose, salicin and d-xylose, which was typical of the species of the genus Sugiyamaella. Analysis of the D1/D2 domains of the large subunit rRNA gene and internal transcribed spacer regions of these strains showed that this species was related to Sugiyamaella lignohabitans and Sugiyamaella marionensis, its closest relatives. Su. xiaguanensis sp. nov. differed by 1.4 % nucleotide substitutions from Su. lignohabitans, and by 1.9 % nucleotide substitutions from Su. marionensis in the D1/D2 sequences. The ITS sequences of Su. xiaguanensis sp. nov. displayed more than 6.5 % nucleotide substitutions from the latter two species, showing that it is a genetically separate 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-Y1884^T (= UFMG-CA-32.1^T = CBS 12683^T), 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-Y1884^T (= UFMG-CA-32.1^T = CBS 12683^T) has been deposited at DDBJ/ENA/GenBank under the accession number MQSX00000000 under version MQSX01000000.