Sporobolomyces inositophilus,a new species of ballistosporous yeast isolated from a dead leaf of Sasa sp. in Japan

A new species of ballistosporous yeast, Sporobolomyces inositophilus was isolated from a dead leaf of Sasa sp. collected at a mountain in Japan. This yeast is assumed to have a close relationship to Sporobolomyces singularis since it produces bilaterally symmetrical ballistospores and pale-coloured colonies and resembles Sporobolomyces singularis in these respects. These two species differ from typical species of Sporobolomyces and seem to constitute a natural taxonomic group.     

Four new yeast species of the genus Sporobolomyces from plant leaves

Among the ballistoconidium-forming yeast strains isolated from various plant leaves collected in North and Northeast China, 12 strains forming orange to orange-red colored colonies were revealed to represent four novel species of the genus Sporobolomyces by conventional, chemotaxonomic and molecular phylogenetic studies, based on the 26S-rDNA D1/D2 domain and internal transcribed spacer (ITS) region sequences. Sporobolomyces beijingensis sp. nov., represented by eight strains (type strain CB 80T = AS 2.2365T = CBS 9730T), and Sporobolomyces jilinensis sp. nov., represented by two strains (type strain CB 118T = AS 2.2301T = CBS 9728T), clustered in the Johnsonii clade of the Sporidiobolus lineage. Sporobolomyces clavatus sp. nov., represented by strain CB 281T (= AS 2.2318T = CBS 9729T), belonged to the Agaricostilbum lineage and showed a close relationship to Sporobolomyces ruber and Sporobolomyces dracophylli. Sporobolomyces symmetricus sp. nov., represented by strain CB 64T(= AS 2.2299T = CBS 9727T), formed nearly symmetrical ballistoconidia and was closely related with Sporobolomyces vermiculatus and Sporobolomyces gracilis in the Gracilis clade of the Erythrobasidium lineage.     

Sporobolomyces yuccicola,a new species of ballistosporous yeast equipped with ubiquinone-9

A hitherto undescribed ballistosporous yeast was isolated from a dead leaf of Yucca sp. in Canada. This yeast produces apiculate or short-ellipsoidal ballistospores, produces pale colored colonies, has Q-9 as the major ubiquinone, and does not contain xylose in the cells. This new yeast is described as Sporobolomyces yuccicola Nakase et Suzuki. Sporobolomyces yuccicola is the sixth species of the intermedius group, a group of atypical species of the genus Sporobolomyces equipped with Q-9.     

Yeast biodiversity in hydromorphic soils with reference to grass-Sphagnum swamp in Western Siberia and the hammocky tundra region( Barrow, Alaska)]

The microbiological analysis of 78 samples taken from a boreal bog in Western Siberia and from a tundra wetland soil in Alaska showed the presence of 23 yeast species belonging to the genera Bullera, Candida, Cryptococcus, Debaryomyces, Hanseniaspora, Metschnikowia, Mrakia, Pichia, Rhodotorula, Saccharomyces, Sporobolomyces, Torulaspora, and Trichosporon. Peat samples from the boreal bog were dominated by eurytopic anamorphic basidiomycetous species, such as Rhodotorula mucilaginosa and Sporobolomyces roseus, and by the ascomycetous yeasts Candida spp. and Debaryomyces hansenii. These samples also contained two rare ascomycetous species (Candida paludigena and Schizoblastosporion starkeyi-henricii), which so far have been found only in taiga wetland soils. The wetland Alaskan soil was dominated by one yeast species (Cryptococcus gilvescens), which is a typical inhabitant of tundra soils. Therefore, geographic factors may serve for a more reliable prediction of yeast diversity in soils than the physicochemical or ecotopic parameters of these soils.     

Assessment of phylloplane yeasts on selected Mediterranean plants by FISH with group- and species-specific oligonucleotide probes

A previous culture-dependent survey of phylloplane yeasts from selected Mediterranean plants showed that a few species were present in high densities in almost all leaf samples, regardless of the plant type, location or sampling season. However, a few species appeared to be restricted to Cistus albidus leaves, namely Cryptococcus cistialbidi . Here, we describe a culture-independent FISH assay to detect and quantify whole yeast cells in leaf washings. After optimization, the technique was used to check the apparent association between C. albidus leaves and C. cistialbidi and the abundance and ubiquity of other basidiomycetous yeast species such as Erythrobasidium hasegawianum and Sporobolomyces spp. in leaf samples from this and other neighboring plants ( Acer monspessulanum and Quercus faginea ). No yeast cells were detected in Pistacia lentiscus leaf samples. We were also able to demonstrate that three phylloplane yeasts ( C. cistialbidi, E. hasegawianum and Sporobolomyces spp.) appeared to be log-normally distributed among individual C. albidus leaves. The log-normal distribution has important implications for the quantification of phylloplane yeasts based on the washing and plating of bulk leaf samples, which will tend to overestimate the size of the respective populations and become an error source in yeast surveys or related biocontrol studies.     

Biotransformation of lignin polymers derived from beech wood pulping by Sporobolomyces roseus isolated from leafy material

The ability of the yeast, Sporobolomyces roseus, isolated from leafy material, to modify lignin derived from beechwood pulping was examined by FTIR and 13C NMR spectroscopy, which revealed oxidative cleavage of the Calpha-Cbeta linkages between lignin units. Using veratryl alcohol as a model substrate confirmed that Sp. roseus could oxidize veratryl alcohol into veratric acid. This yeast might be suitable for the pretreatment of lignocellulosic materials and/or for biotransformation of technical lignins.     

Nucleotide Composition of Deoxyribonucleic Acid of Some Species of Cryptococcus, Rhodotorula, and Sporobolomyces

The buoyant density of deoxyribonucleic acid (DNA) from nine species and two varieties of Cryptococcus, three species and two varieties of Rhodotorula, and six species of Sporobolomyces was determined by CsCl density gradient equilibrium centrifugation. Several species were represented by two to four different strains. Expressed in moles per cent of guanine plus cytosine (GC content) the ranges were 49 to 65%, 52 to 70%, and 51 to 65% for Cryptococcus, Rhodotorula, and Sporobolomyces, respectively. For each genus, the GC content was distributed into two discrete groups with averages ranging from 52 to 54 and 60 to 66, respectively. An analysis of these results suggested that the determination of GC content of DNA had a taxonomic value for these yeast genera.     

Dimorphism in Itersonilia perplexans: Yeast and hyphal phases differ in their sensitivity to mycocins produced by tremellaceous yeasts

The monokaryotic yeast phase of the heterobasidiomycete Itersonilia perplexans, unlike the hyphal phase, was found to be sensitive to mycocins produced by killer strains of Cryptococcus humicola, Cr. laurentii, Cystofilobasidium bisporidii and Rhodotorula fujisanense. Both the yeast and hyphal phases wer resistant to mycocins of Cr. podzolicus, Filobasidium capsuligenum, Rhodotorula glutinis, Rh. mucilaginosa, Rh. pallida, Sporidiobolus johnsonii, Sb. pararoseus and Sporobolomyces alborubescens. The different sensitivity patterns of yeast and hyphal phases are probably caused by biochemical differences in the cell walls.     

Transformation of D-xylose by sporobolomyces lactosus

The new yeast species, Sporobolomyces lactosus, transformed D-xylose into a mixture of disaccharides. Hydrolysis of this mixture yielded D-glucose only. The main component of disaccharide mixture was α,α-trehalose.     

Production of biotin by yeasts

A quantitative screening procedure for biotin and biotin vitamer production was conducted on 129 yeast strains able to grow in a biotin-free medium. Production of biotin and biotin vitamers varied considerably from strain to strain even within a species. The best producers of biotin were strains of Sporobolomyces roseus and Rhodotorula rubra whilst strains of Rhodotorula rubra and Yarrowia lipolytica produced the largest amounts of vitamers.     

Sporobolomyces salmonicolor var. fischerii,a new yeast

A new variety of Sporobolomyces salmonicolor, a basidiomycetous yeast isolated from the cerebrospinal fluid of a human case of meningitis has been described. The variety can be differentiated from the species primarily by its ability to assimilate D-galactose and L-arabinose.     

Yeast Diversity in Hydromorphic Soils with Reference to a Grass–Sphagnum Wetland in Western Siberia and a Hummocky Tundra Region at Cape Barrow (Alaska)

The microbiological analysis of 78 samples taken from a high bog in Western Siberia and from a tundra wetland soil in Alaska showed the presence of 23 yeast species belonging to the genera Bullera, Candida, Cryptococcus, Debaryomyces, Hanseniaspora, Metschnikowia, Mrakia, Pichia, Rhodotorula, Saccharomyces, Sporobolomyces, Torulaspora, and Trichosporon.Peat samples from the high bog were dominated by eurytopic anamorphic basidiomycetous species, such as Rhodotorula mucilaginosaand Sporobolomyces roseus, and by the ascomycetous yeasts Candidaspp. and Debaryomyces hansenii.These samples also contained two rare ascomycetous species (Candida paludigenaand Schizoblastosporion starkeyi-henricii), which so far have been found only in taiga wetland soils. The wetland Alaskan soil was dominated by one yeast species (Cryptococcus gilvescens), which is a typical inhabitant of tundra soils. Therefore, geographic factors may serve for a more reliable prediction of yeast diversity in soils than the physicochemical or ecotopic parameters of these soils.     

Four new species of yeast isolated from insect frass in bark ofTsuga heterophylla (Raf.) Sargent

Summary In a study of the yeasts associated with insect frass underneath the bark ofTsuga heterophylla (the Pacific Coast hemlock) four new species of yeast were found. These were described asSporobolomyces singularis, Bullera tsugae, Cryptococcus skinneri andCandida oregonensis. Sporobolomyces singularis is a non-pigmented species, which required an amendment of the genus definition. Ballistospore formation of the new species ofSporobolomyces and ofBullera was absent on malt agar and on potato glucose agar, but positive on corn meal agar. An unusual case of quantitative transgalactosylation by growing cells ofSporobolomyces singularis on lactose has been described. It has been proposed to establish a “Candida parapsilosis Group” of species to whichC. oregonensis was assigned. Supported by a fellowship of the Calouste Gulbenkian Foundation, Lisbon, Portugal.     

Carotenoid profiles of yeasts belonging to the genera Rhodotorula, Rhodosporidium, Sporobolomyces, and Sporidiobolus

Eighteen yeast species of the genera Rhodotorula, Rhodosporidium, Sporobolomyces, and Sporidiobolus, each one represented by its type strain, were investigated with the objective of evaluating their carotenoid composition. The pigments were extracted from yeast cells, quantified by high pressure liquid chromatography diode array detector and the main compounds were confirmed by atmospheric pressure chemical ionization quadrupole mass spectrometry. Significant (P < 0.01) differences among several species and (or) genera were observed. Thirteen strains were seen to be able to produce carotenoids, from 16.4 to 184 microg/g cell dry mass and from 6.0 to 1993.4 microg/L culture. The main carotenoids produced were identified as torularhodin, torulene, gamma-carotene, and beta-carotene. The correlation matrix calculated on the basis of the carotenoid composition data matrix indicated significant (P < 0.01) relationships between torulene and torularhodin (r = 0.81), gamma-carotene and torulene (r = 0.49), beta-carotene and torulene (r = -0.72), as well as beta-carotene and gamma-carotene (r = 0.64). These significant correlation coefficients may suggest that species belonging to the genera Rhodosporidium, Sporobolomyces, and Sporidiobolus possess a carotenoid biosynthetic pathway analogous to that elsewhere postulated for Rhodotorula species.     

The perfect and imperfect states ofSporobolomyces salmonicolor

A strain ofSporobolomyces salmonicolor from which both the haplophase and diplophase had been recovered was found to form teliospores which germinated usually by the formation of a non-septate promycelium bearing 2–4 sporidia. The strain has consequently been transferred to the new basidiomycetous yeast genusAessosporon, for which a diagnosis and type are given, and which has been assigned to the Tilletiaceae.     

Enhanced antioxidant formula based on a selenium-supplemented carotenoid-producing yeast biomass

Carotenoid-producing yeast species such as Rhodotorula glutinis and Sporobolomyces roseus efficiently accumulated selenium from the growth medium. It was observed that incorporation of selenium into yeast cells during the growth inhibited production of beta-carotenoid and other carotenoid precursors (torularhodin and torulene). The yeasts with high content of the carotenoid pigments and selenium may be used for the preparation of a new type of antioxidant formula that could be directly applied for various human and animal diets. We have demonstrated that such a formula can only be produced by separate processes of the cultivation of red yeasts and a subsequent sorption of selenium into the cells.     

A modified method for testing inositol assimilation by Cryptococcus species.

The proposed method for rapid testing of inositol assimilation incorporates shake cultures in an indicator-based broth containing inositol (1%), yeast nitrogen base (0.067%), bromocresol purple, and a heavy inoculum. Of 153 yeast isolates investigated, inositol assimilation was shown with the modified method, as also by the Adams-Cooper procedure, in all the 123 isolates, representing 11 species of Cryptococcus. The results were negative by both the methods in the remaining 30 isolates belonging to Candida, Rhodotorula, Torulopsis, Pichia, Saccharomyces, and Sporobolomyces. The modified method was found to be significantly more effective than the Adams-Cooper procedure; the results could be read within 36 h by the former as against 336 h by the latter method. The superiority of the modified method to the Adams-Cooper procedure is attributed to increased aeration in shake cultures, a heavier inoculum, and reduced concentration of yeast nitrogen base.     

Production of biomass, carotenoid and other lipid metabolites by several red yeast strains cultivated on waste glycerol from biofuel production – a comparative screening study

This study was focused on a comparison of growth and production properties of seven red yeast strains of the genus Rhodotorula, Sporobolomyces and Cystofilobasidium cultivated on glycerol substrate. Production of enriched yeast biomas and specific yeast metabolites (carotenoids, ergosterol, lipids) was evaluated on medium with glucose, pure technical glycerol and/or waste glycerol from biofuel production (40 g/L) and mixture of glycerol and glucose (1:3, 1:1, 3:1; C/N ratio 57 in all cultivations). All tested strains were able to utilize glycerol as the only carbon source. Production of biomass on waste glycerol was in most strains higher than in control as well as in medium with pure technical glycerol and reached 15.97–21.76 g/L. Production of carotenoids and ergosterol was better in glucose medium than in medium with glycerol only. Nevertheless, using glycerol medium with addition of glucose, higher yields of total carotenoids, beta-carotene and ergosterol were obtained than in control. The highest yields of total pigments were reached by Sporobolomyces roseus (3.60 mg/g cell dry weight (CDW); glycerol:glucose 1:3), Sporobolomyces salmonicolor (2.85 mg/g CDW; glycerol:glucose 1:3) and Rhodotorula glutinis (2.80 mg/g CDW; glycerol:glucose 3:1) In glucose medium, most tested strains except Cystofilobasidium capitatum (22.6 %) produced neutral lipids in the range of 11–15 %. Production of triacylglycerols in all strains was in 10–30 % better in glycerol medium, in which Rhodotorula aurantiaca and Sporobolomyces shibatanus also reached intracellular triacylglycerol concentrations up to 20 % of biomass. This study has shown that oleaginous red yeasts could have great potential for converting crude glycerol to valuable lipids and carotenoids in respect of efficient bioresources utilization.     

Activity of exoglycans as sorbents of heavy metal ions]

The ability of yeast exoglycans (from Cryptococcus laurentii, Cr. luteolus, and Sporobolomyces albo-rubescens) to absorb copper and lead ions has been studied. The sorption isotherms have been obtained, which indicates that the mechanism of interactions in the system polysaccharide-metal is complex. For the majority of the glycans, the absorption selectivity was considerably higher in the case of copper, as compared to lead. The observed discrepancy in the effects of pH and temperature on the absorption indicates that the bonds mediating ion absorption by glycans are of different nature. In conclusion, yeast exoglycans are efficient sorbents of copper and lead ions, and lutelan is the most active exoglycan in this respect.     

Screening for microorganism with cell wall lytic activity to produce protoplast-forming enzymes

Several different bacteria and fungi capable of degrading yeast cell walls were isolated in the course of a screening programme. One Streptomyces and one Acremonium strain were found to degrade yeast cell walls extremely well. Both isolates produced enzymes in liquid culture that could be used for protoplasting of Sporobolomyces salmonicolor (DSM 70851) and Rhodotorula rubra (DSM 70403). This fact is quite remarkable as, so far, S. salmonicolor could not be protoplasted by commercially available enzymes. Correspondence to: W. Kaul