Candida Maltosa Research Articles

Chemical profiling of fungal metabolites via the OSMAC approach: Novel identification of Brianthein W from an endophytic fungus, Hypomontagnella monticulosa Zg15SU

In the previous report, we reported that Hypomontagnella monticulosa originating from the rhizome of Zingiber griffithii was known to produce a marine-derived natural product. An OSMAC-based approach was designed by modifying the nutritional composition of the growth medium to investigate any possible new metabolites produced by the strain. The culture filtrate and biomass were conditioned through the use of three basal media, namely, Czapek-dox, potato dextrose, and Wickersham broth medium. GC-MS and multivariate analysis was performed to distinguish the chemicals and determine their composition in the tested extracts. Antimicrobial activity was tested against selected human pathogenic microbes using the disk-diffusion method. The MeOH extract of both culture filtrate and biomass from different fermentation media revealed that the majority of identified compounds (n=40) were found in Wickerham medium (n=23), which is later termed as MeOH-Wi. The chemical composition of MeOH-Wi was fatty acids (21.74%), followed by terpenoids (17.38%), cyclosiloxane (13.04%), aldehydes (13.04%), alkenes (8.7%), hydrocarbons (8.7%), esters (8.7%), alkaloids (4.35%), and an unclassified compound, the 9,9-Dimethyl-3,7-diazabicyclo[3.3.1]nonane. The numerous chemical compounds in MeOH-Wi corresponded with its antimicrobial activities against Micrococcus luteus NBRC 13867 (±11 mm), Candida maltosa NBRC 1977 (±9 mm), and Escherichia coli JM 109 (±5 mm) which were higher than the other tested extracts. Further purification using HPLC RP-C18 using NP-SiO2/n-Hex–EtOAc (10:2) to yield compound (1). Compound (1) was determined as an analog of briarian W—a diterpene mostly found in marine sponge, Briareum spp.—as a pure compound in the MeOH extract of H. monticulosa based on the 1D and 2D NMR analysis. The anticancer activity (IC50) of compound (1) was 0.077, 0.080, and 0.102 µg/mL against the growth of HCT-116, NBT-T2, and Panc-1, respectively. As far as we are aware, this is the first report on finding a briarian diterpene that originates from an endophytic fungus, especially by H. monticulosa.

Cr(VI) removal performance from wastewater by microflora isolated from tannery effluents in a semi-arid environment: a SEM, EDX, FTIR and zeta potential study.

Hexavalent chromium removal from the environment remains a crucial worldwide challenge. To address this issue, microbiological approaches are amongst the straightforward strategies that rely mainly on the bacteria's and fungi's survival mechanisms upon exposure to toxic metals, such as reduction, efflux system, uptake, and biosorption. In this work, scanning electron microscopy, energy-dispersive X-ray spectrophotometry, Fourier transform infrared spectroscopy, and zeta potential measurements were used to investigate the ability of chromium adsorption by Bacillus licheniformis, Bacillus megaterium, Byssochlamys sp., and Candida maltosa strains isolated from tannery wastewater. Scanning electron microscopy combined with energy dispersive X-ray spectroscopy revealed alterations in the cells treated with hexavalent chromium. When exposed to 50 mg/L Cr6+, Bacillus licheniformis and Candida maltosa cells become rough, extracellular secretions are reduced in Bacillus megaterium, and Byssochlamys sp. cells are tightly bound and exhibit the greatest Cr weight percentage. In-depth analysis of Fourier transform infrared spectra of control and Cr-treated cells unveiled Cr-microbial interactions involving proteins, lipids, amino acids, and carbohydrates. These findings were supported by zeta potential measurements highlighting significant variations in charge after treatment with Cr(VI) with an adsorption limit of 100 mg/L Cr6+ for all the strains. Byssochlamys sp. showed the best performance in Cr adsorption, making it the most promising candidate for treating Cr-laden wastewater.

Yeast Diversity in Honey and Pollen Samples from Stingless Bees in the State of Bahia, Brazil: Use of the MALDI-TOF MS/Genbank Proteomic Technique.

(1) Background: The identification of microorganisms includes traditional biochemical methods, molecular biology methods evaluating the conserved regions of rRNA, and the molecular biology of proteins (proteomics), such as MALDI-TOF MS mass spectrometry. This work aimed to identify the biodiversity of yeasts associated with stingless bee species' honey and pollen, Melipona scutellaris, Nannotrigona testaceicornes, and Tetragonisca angustula, from the region of São Gonçalo dos Campos-Bahia (BA) state, Brazil. (2) Methods: Cellular proteins were extracted from 2837 microbial isolates (pollen and honey) and identified via MALDI-TOF MS. The identified yeast species were also compared to the mass spectra of taxonomically well-characterized reference strains, available from the National Center of Biotechnology Information (NCBI) database. (3) Results: Nine yeast species were identified: Candida maltosa, Candida norvegica, Kazachstania telluris, Schizosaccharomyces pombe, Scheffersomyces insectosus, Meyerozyma guilliermondii, Brettanomyces bruxellensis, Kazachstania exigua, and Starmerella lactis-condensi. Nannotrigona testaceicornes pollen had the highest number of yeast colonies. The yeasts Brettanomyces bruxellensis and Kazachstania telluris showed high populations in the samples of Nannotrigona testaceicornes and Melipona scutellaris, respectively. This work shows that there is some sharing of the same species of yeast between honey and pollen from the same beehive. (4) Conclusions: A total of 71.84% of the identified species present a high level of confidence at the species level. Eight yeast species (Candida maltosa, Candida norvegica, Kazachstania telluris, Schizosaccharomyces pombe, Scheffersomyces insectosus, Meyerozyma guilliermondii, Kazachstania exigua, and Starmerella lactis-condensi) were found for the first time in the samples that the authors inspected. This contributes to the construction of new knowledge about the diversity of yeasts associated with stingless bee products, as well as to the possibility of the biotechnological application of some yeast species.

Genetic modification of Candida maltosa, a non-pathogenic CTG species, reveals EFG1 function.

Candida maltosa is closely related to important pathogenic Candida species, especially C. tropicalis and C. albicans, but it has been rarely isolated from humans. For this reason, through comparative studies, it could be a powerful model to understand the genetic underpinnings of the pathogenicity of Candida species. Here, we generated a cohesive assembly of the C. maltosa genome and developed genetic engineering tools that will facilitate studying this species at a molecular level. We used a combination of short and long-read sequencing to build a polished genomic draft composed of 14 Mbp, 45 contigs and close to 5700 genes. This assembly represents a substantial improvement from the currently available sequences that are composed of thousands of contigs. Genomic comparison with C. albicans and C. tropicalis revealed a substantial reduction in the total number of genes in C. maltosa. However, gene loss seems not to be associated to the avirulence of this species given that most genes that have been previously associated with pathogenicity were also present in C. maltosa. To be able to edit the genome of C. maltosa we generated a set of triple auxotrophic strains so that gene deletions can be performed similarly to what has been routinely done in pathogenic Candida species. As a proof of concept, we generated gene knockouts of EFG1, a gene that encodes a transcription factor that is essential for filamentation and biofilm formation in C. albicans and C. tropicalis. Characterization of these mutants showed that Efg1 also plays a role in biofilm formation and filamentous growth in C. maltosa, but it seems to be a repressor of filamentation in this species. The genome assembly and auxotrophic mutants developed here are a key step forward to start using C. maltosa for comparative and evolutionary studies at a molecular level.

High-Temperature, Noncatalytic Oxidation of Polyethylene to a Fermentation Substrate Robustly Utilized by Candida maltosa

High-Temperature, Noncatalytic Oxidation of Polyethylene to a Fermentation Substrate Robustly Utilized by <i>Candida maltosa</i>

Valorization of spent coffee grounds through integrated bioprocess of fermentable sugars, volatile fatty acids, yeast-based single-cell protein and biofuels production

Recovering nutrients from waste for biological processes aligns with sustainability principles. This study aimed to convert spent coffee grounds (SCG) into valuable products, including fermentable sugars, volatile fatty acids (VFAs), yeast-based single-cell protein and biofuels. Alkaline pretreatment was conducted before enzymatic hydrolysis, in which the pretreated SCG was hydrolyzed with varying enzyme loadings (20–60 filter paper units (FPU)/g-solid) and solid loadings (3–15 % w/v). The hydrolyzed slurry was utilized for VFAs and hydrogen production, yielding high values of 0.66 g/g-volatile solids (VS) and 109 mL/g-VS, respectively, using an enzyme loading of 50 FPU/g-solid and a solid loading of 3 % (w/v). The derived VFAs were used to cultivate a newly isolated yeast, Candida maltosa KKU-ARY2, resulting in an accumulated protein content of 43.7 % and a biomass concentration of 4.6 g/L. This study highlights the conversion of SCG into essential components, emphasizing the benefits of waste utilization through cascade bioprocesses.

Antimicrobial activity of extracellular compounds from endophytic fungus BAR1.5 cultivated with different media

Endophytic fungi are microorganisms that live inside the plants that are known to be able to produce the same bioactive compounds as their host plants. Endophytic fungus BAR1.5 was isolated from Rhizophora stylosa leaves collected from the mangrove area of Barru, South Sulawesi. The extracellular components of fungal endophytes are known to have higher antimicrobial activity than the intracellular compounds. Furthermore, the growth of endophytic fungi is strongly influenced by nutrients in the culture media, so that it may affect the production of its secondary metabolites. The aim of this study was to compare the production of extracellular compounds and its antimicrobial activity of the fungus BAR 1.5 cultured with different media (Potato Dextrose Broth, PDB and Hagem medium). The results showed that the endophytic fungus cultured on PDB media grew faster, produced more yield of extracts and showed stronger antimicrobial activity. Its extracellular compounds inhibited the growth of the tested bacteria which were Escherichia coli, Pseudomonas aeruginosa, Candida maltosa, Bacillus subtilis and Staphylococcus aureus. The strongest antibacterial activity was against B. subtilis with the inhibition zone was 12.5±0.3 mm. The extracellular compounds of the endophytic fungus BAR 1.5 contained terpenoids, polyphenols, and flavonoids.

The Extracellular Vesicles Containing Inorganic Polyphosphate of Candida Yeast upon Growth on Hexadecane.

The cell wall of Candida yeast grown on presence of hexadecane as a sole carbon source undergoes structural and functional changes including the formation of specific supramolecular complexes-canals. The canals contain specific polysaccharides and enzymes that provide primary oxidization of alkanes. In addition, inorganic polyphosphate (polyP) was identified in Candida maltosa canals. The aim of the work was a comparative study of the features of cell walls and extracellular structures in yeast C. maltosa, C. albicans and C. tropicalis with special attention to inorganic polyphosphates as possible part of these structures when grown on the widely used xenobiotic hexadecane (diesel fuel). Fluorescence microscopy with DAPI has shown an unusual localization of polyP on the cell surface and in the exovesicles in the three yeast species, when growing on hexadecane. Electron-scanning microscopy showed that the exovesicles were associated with the cell wall and also presented in the external environment probably as biofilm components. Treatment of hexadecane-grown cells with purified Ppx1 polyphosphatase led to the release of phosphate into the incubation medium and the disappearance of polyP in vesicles and cell wall observed using microscopic methods. The results indicate the important role of polyP in the formation of extracellular structures in the Candida yeast when consuming hexadecane and are important for the design of xenobiotic destructors based on yeast or mixed cultures.

Effect of the temperature and osmotic stress on the growth and cell viability of Candida maltosa

The present research attempted to observe the temperature and osmotic stress effects on yeast species in cheese. The Candida maltosa yeast was isolated from locally made raw cheese samples, and it was identified by its biochemical properties, followed by using the BIOLOGTM microbial identification system to confirm species level identification. The study investigate about Candida maltosa's ability to grow and develop a budding pattern under high temperatures up to 44°C and osmotic stress for 72 h. Osmotic stress tolerance was studied at 32.5°C in different concentrations of dextrose (0.04 g/l, 0.12 g/l, 0.2 g/l, 0.28 g/l, and 0.36 g/l) and sucrose (0.02 g/l, 0.06 g/l, and 0.36 g/l), respectively. Cell growth of the C. maltosa was measured by optical density at 600nm (OD600) and the enumeration of colony forming units (CFUs) on the agar plates up to 300 m. The obtained result indicated the optimal growth pattern at 32.5°C and complete growth retardation at 44°C with the high concentrations of dextrose (0.36 g/l) and sucrose (0.38 g/l). Particularly, C. maltosa budding could only survive 240 m at 37°C to 40°C and was suppressed at 44°C. The experimental findings demonstrated the stress response in yeast cells in the phenotypic level with the existing acquaintance on the osmotic stress response actions in C. maltosa. Bangladesh J. Sci. Ind. Res. 58(2), 71-78, 2023

Microorganisms from tannery wastewater: Isolation and screening for potential chromium removal

Chromium is a chemical element that enables many industries to function. However, its hexavalent form can cause serious problems. The current methods used to remove Cr are expensive and cause environmental damages, hence the need to set up the most environment friendly methods like the biological methods. The main objectives of this study were isolation, characterization of hexavalent chromium removing microorganisms from Marrakech tannery wastewater. Four microbial strains namely Bacillus licheniformis, Bacillus megaterium, Byssochlamys sp. and Candida maltosa were selected and identified using molecular methods. Candida maltosa and Byssochlamys sp. produce antimicrobial metabolites that have a microbiostatic effect. Bacillus licheniformis, Bacillus megaterium and Candida maltosa removed 92.75; 75.48 and 43.27% of hexavalent chromium at the concentration of 50 mg/L in 96 h respectively. In contrast, Byssochlamys sp. removed 100% of 50 mg/L of hexavalent chromium concentration in 72 h. At 100 mg/L of hexavalent chromium, it was recorded that Bacillus licheniformis, Bacillus megaterium, Byssochlamys sp., Candida maltosa, consortium C reduced 41.20; 50.88; 64.44; 31.88; 57.30% in 96 h respectively. Byssochlamys sp. strain could be the best candidate for bioremediation of chromium contaminated leather industry effluent and metal recovery in mining process.

Mycobiome Dysbiosis in Women with Intrauterine Adhesions.

ABSTRACTThe vaginal microbiota dysbiosis is closely associated with the development of reproductive diseases. However, the contribution of mycobiome to intrauterine adhesion (IUA) disease remains unknown. Harnessing 16S and ITS2 rDNA sequencing analysis, we investigate both bacterial and fungal microbiota compositions across 174 samples taken from both cervical canal (CC) and middle vagina (MV) sites of IUA patients. Overall, there is no significant difference in microbial diversity between healthy subjects (HS) and IUA patients. However, we observe the IUA-specific bacterial alterations such as increased Dialister and decreased Bifidobacterium and enriched fungal genera like increased Filobasidium and Exophiala. Moreover, site-specific fungal-bacterial correlation networks are discovered in both CC and MV samples of IUA patients. Mechanistic investigation shows that Candida parapsilosis, other than Candida albicans and Candida maltosa, prevents the exacerbation of inflammatory activities and fibrosis, and modulates bacterial microbiota during IUA progression in a rat model of IUA. Our study thus highlights the importance of mycobiota in IUA progression, which may facilitate the development of therapeutic target for IUA prevention.IMPORTANCE Intrauterine adhesion (IUA) often leads to hypomenorrhea, amenorrhea, repeat miscarriages, and infertility. It has been prevalent over the last few decades in up to 13% of women who experience pregnancy termination during the first trimester, and 30% of women undergo dilation and curettage after a late, spontaneous abortion. However, the pathogenesis of IUA remains unclear. Despite reports of microbiota dysbiosis during IUA progression, there is little information on the effect of fungal microbiota on the development of IUA. This study not only enhances our understanding of the mycobiome in IUA patients but also provides potential intervention strategies for prevention of IUA by targeting mycobiome.

Crude Aqueous Root Extracts of Solanum spp. Show Nematotoxic Activity Against Meloidogyne incognita

Brazilian crops are strongly affected by the root-knot nematode Meloidogyne incognita, which compromises food production and causes serious economic losses around the world. Synthetic nematicides are still some of the main control strategies for this pathogen, despite the high risk to human health and the environment. Therefore, sustainable biotechnology represents a viable alternative for nematode control. Plants of the Solanaceae family are present in several biomes and are a source of secondary metabolites of various chemical classes. In this context, the nematotoxic effect of crude aqueous root extracts (CAREs) of three Solanum species was investigated: Solanum americanum, S. subinerme and S. lycocarpum. CARE showed high nematicidal activity (94.6&amp;plusmn;9.2% mortality, p &amp;le; 0.001) against second-stage juveniles (J2) of M. incognita, even after heating to 50 &amp;deg;C. These CAREs also inhibited hatching of juveniles (98.4&amp;plusmn;0.7% of mortality, p &amp;le; 0.001) in addition to presenting a mean lethal dose of 336 &amp;mu;g ml-1. No toxic activity was observed against non-target organisms, such as fungi (Trichoderma harzianum and Trichoderma asperellum), yeast (Candida maltosa), nitrogen-fixing bacteria (Bradyrhizobium diazoefficiaens, B. japonicum), two strains of Azospirillum brasilense, AbV 5 and AbV 6 and Bacillus [2538 Ba]. Bioassay performed in a greenhouse demonstrated that CAREs of these species were effective in reducing the number of egg masses and galls (&amp;gt; 85%, p &amp;le; 0.0001), and did not show a phytotoxic effect on soybean seedlings. Our findings indicate that CAREs from plants of the Solanaceae family, especially S. lycocarpum, demonstrated nematotoxic activity on J2 and inhibited the hatching of Meloidogyne incognita eggs, representing an ecologically appropriate tool to control nematode infection in crops worldwide.

Antiviral Agents and Biological Preparations for Agriculture Based on Artificial Glycan-Glycolipid Complexes

On the way of development of antiviral agents for agriculture, artificial glycan-glycolipid complexes (GGC) were created from glucan, which was the component of mycelium of basidiomicotafungi Ganoderma adspersum (Schulzer) Donk. Other constituents are extracellular glucouronoxylomannan of basidiomicota fungi Tre-mella mesenteric Ritz. Fr., mannan from Candida maltosa cells. Ramnolipid of Pseudomonas sp. PS-17 is used as a compound agent, аnd GGC fractions (liposomes and supernatant) have an inhibit in gactivity against virus of tabacum mosaic (VТM) of datura (Datura stramonium (L.) and tabacum (Nicotiana tabacum L.) plants up-sensitive to this virus. Under by the treatment of soybean (Glycine max (L.) Merr.) Seeds bio formulations, the plant resistance to mosaic virus infections (diseases) and the reflection of leaf light spectra, which characterized of chlorophill sunder field conditions, are increased. Using the electron microscope method of investigation, the structures of microcenoses as well as liposoms were found out in the near-root plant zone, which indicates on the lack of impact to the processes of plant-rhyzospheric microorganism’s interactions. The investigation has shown that pre-sowing bacterization by Brady rhizobium japonicum UCM B-6018 in combination with GGC-3 preparation promotes the crop increase in field experiments.

Survey of nonconventional yeasts for lipid and hydrocarbon biotechnology.

Nonconventional yeasts have an untapped potential to expand biotechnology and enable process development necessary for a circular economy. They are especially convenient for the field of lipid and hydrocarbon biotechnology because they offer faster growth than plants and easier scalability than microalgae and exhibit increased tolerance relative to some bacteria. The ability of industrial organisms to import and metabolically transform lipids and hydrocarbons is crucial in such applications. Here, we assessed the ability of 14 yeasts to utilize 18 model lipids and hydrocarbons from six functional groups and three carbon chain lengths. The studied strains covered 12 genera from nine families. Nine nonconventional yeasts performed better than Saccharomyces cerevisiae, the most common industrial yeast. Rhodotorula toruloides, Candida maltosa, Scheffersomyces stipitis, and Yarrowia lipolytica were observed to grow significantly better and on more types of lipids and lipid molecules than other strains. They were all able to utilize mid- to long-chain fatty acids, fatty alcohols, alkanes, alkenes, and dicarboxylic acids, including 28 previously unreported substrates across the four yeasts. Interestingly, a phylogenetic analysis showed a short evolutionary distance between the R. toruloides, C. maltosa, and S. stipitis, even though R. toruloides is classified under a different phylum. This work provides valuable insight into the lipid substrate range of nonconventional yeasts that can inform species selection decisions and viability of lipid feedstocks.

Residual Brewing Yeast as Substrate for Co-Production of Cell Biomass and Biofilm Using Candida maltosa SM4

Candida maltosa was cultivated in the liquid phase of residual brewing yeast, a major brewery residue, to produce biomass and biofilm. Using response surface methodology, the effect of two variables at two different levels was investigated. The independent variables were agitation speed (at 100 and 200 rpm), and aeration (at 1 and 3 L min−1). Aeration was identified to be important for the production of both biomass and biofilm, while agitation was the only factor significantly affecting biofilm production. The maximal production of biofilm (2.33 g L−1) was achieved for agitation of 200 rpm and aeration of 1 L min−1, while the maximum for biomass (16.97 g L−1) was reached for 100 rpm agitation and 3 L min−1 air flow. A logistic model applied to predict the growth of C. maltosa in the exponential phase and the biofilm production, showed a high degree of agreement between the prediction and the actual biomass measured experimentally. The produced biofilms were further characterized using Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA). FTIR allowed the identification of methyl, carbonyl ester and sulfate groups, and revealed the presence of uronic acid moieties and glycosidic bonds. Water-retention ability up to relatively high temperatures was revealed by TGA, and that makes the produced biofilm suitable for production of hydrogels. SEM also gave indications on the hydrogel-forming potential of the biofilm.

Changes in cell wall structure and protein set in Candida maltosa grown on hexadecane.

The yeast Candida maltosa is a model organism for studying adaptive changes in the structure and function of the cell wall when consuming water-insoluble nutrient sources. The cells of C. maltosa that utilize hydrocarbons contain supramolecular structures, so-called "canals" in the cell wall. Differences in protein profiles of culture liquids and cell wall extracts of C. maltosa grown on glucose and hexadecane were analyzed. Three proteins specific of cells grown on hexadecane were revealed using mass spectrometry: glycosyl hydrolase EPD2 in the culture liquid; a protein belonging to the cytochrome C family in the 0.5 mol/L NaCl extract; and PPIA_CANAL protein known as chaperone, in the 0.1% SDS extract. The possible role of these proteins in cell wall structures responsible for adaptation to hexadecane utilization is discussed.

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.

In silico and in vitro comparison of nicotinamide adenine dinucleotide phosphate dependent xylose reductase rossmaan fold in Debaryomycetaceae yeast family

abstract Meyerozyma caribbica is prominently used for the production of xylitol from agro waste hydrolysate of the corncob. M. caribbica was isolated from fermented apple juice, the nicotinamide adenine dinucleotide phosphate (NADP) dependent xylose reductase (XR) enzyme act as a catalyst for the production of xylitol from xylose during xylose fermentation by M. caribbica. The enzyme XR was extracted, partially purified, sequenced and molecular weight was determined by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF). This study explores the in silico and in vitro comparative analysis of the cofactor NADP binding mechanism in rossmann fold of isolated M. caribbica and other xylose fermenting Debaryomycetaceae family yeast. The rossmaan fold analysis of M. caribbica and Debaryomycetaceae family of yeast revealed, xylose fermenting organisms such as Scheffersomyces stipitis, Debaryomyces hansenii, Debaryomyces nepalensis, Candida parapsilosis, Candida maltosa have divergence structure of rosmann fold. Whereas M. caribbica and Candida tenuis has unique structure of rossmann fold. Also, the identified rossmann fold of Debaryomycetaceae family yeast and isolated M. caribbica are conserved to interact with cofactor NADP by H2 bonding, which displays the proximity evolutionary relationship of the enzyme in Debaryomycetaceae family yeast. Annotation analysis showed the isolated M. caribbica has the ability of aldopentose fermentation for xylitol production.

Candida yunnanensis sp. nov. and Candida parablackwelliae sp. nov., two yeast species in the Candida albicans/Lodderomyces clade

During studies on the yeast communities associated with rotting wood in the Xishuangbanna Tropical Rainforest in PR China, four novel yeast strains were found. Phylogenetic analysis based on the concatenated sequences of the D1/D2 domains of the large subunit rRNA gene and the ITS regions showed that these strains represented two novel species in the Candida albicans/Lodderomyces clade. The novel species, represented by strains NYNU 17948 and NYNU 17981, formed a clade with Candida maltosa and Candida baotianmanensis, with 1-1.8% sequence divergence in the D1/D2 domains and 8.9-10% sequence divergence in the ITS regions. The other novel species, represented by NYNU 17105 and NYNU 17763, is most closely related to Candida blackwelliae with 0.7 % sequence divergence in the D1/D2 domains and 6.9 % sequence divergence in the ITS regions. The two novel species could be distinguished from their closest described species in terms of physiological traits. The two novel species are described as Candida yunnanensis sp. nov. (holotype NYNU 17948) and Candida parablackwelliae sp. nov. (holotype NYNU 17763).

Fungal biotransformation of short-chain n-alkylcycloalkanes.

The cycloalkanes, comprising up to 45% of the hydrocarbon fraction, occur in crude oil or refined oil products (e.g., gasoline) mainly as alkylated cyclohexane derivatives and have been increasingly found in environmental samples of soil and water. Furthermore, short-chain alkylated cycloalkanes are components of the so-called volatile organic compounds (VOCs). This study highlights the biotransformation of methyl- and ethylcyclohexane by the alkane-assimilating yeast Candida maltosa and the phenol- and benzoate-utilizing yeast Trichosporon mucoides under laboratory conditions. In the course of this biotransformation, we detected 25 different metabolites, which were analyzed by HPLC and GC-MS. The biotransformation process of methylcyclohexane in both yeasts involve (A) ring hydroxylation at different positions (C2, C3, and C4) and subsequent oxidation to ketones as well as (B) oxidation of the alkyl side chain to hydroxylated and acid products. The yeast T. mucoides additionally performs ring hydroxylation at the C1-position and (C) oxidative decarboxylation and (D) aromatization of cyclohexanecarboxylic acid. Both yeasts also oxidized the saturated ring system and the side chain of ethylcyclohexane. However, the cyclohexylacetic acid, which was formed, seemed not to be substrate for aromatization. This is the first report of several new transformation reactions of alkylated cycloalkanes for eukaryotic microorganisms.