-
Indian Journal of Microbiology Dec 2015In this work, 12 different yeast strains were evaluated to gauge their ability to accumulate lipids using raw glycerol as the main carbon source. Lipomyces lipofer NRRL...
In this work, 12 different yeast strains were evaluated to gauge their ability to accumulate lipids using raw glycerol as the main carbon source. Lipomyces lipofer NRRL Y-1155 stood out above the other strains, achieving 9.48 g/l biomass, 57.64 % lipid content and 5.46 g/l lipid production. The fatty acid profile was similar to vegetable oils commonly used in the synthesis of biodiesel, with the predominance of polyunsaturated acids, especially linoleic acid, reaching 68.3 % for Rhodotorula glutinis NRRL YB-252. The occurrence of palmitic acid (39.3 % for Lipomyces starkeyi NRRL Y-11557) was also notable. Thus, yeast biomass with high lipid content can be a sustainable and renewable alternative as a raw material for the biodiesel industry.
PubMed: 26543267
DOI: 10.1007/s12088-015-0533-9 -
Medical Mycology Journal 2015Bloodstream infection due to Rhodotorula glutinis is extremely rare and mostly associated with underlying immunosuppression or cancer. Vascular access devices provide...
Bloodstream infection due to Rhodotorula glutinis is extremely rare and mostly associated with underlying immunosuppression or cancer. Vascular access devices provide the necessary surfaces for biofilm formation and are currently responsible for a significant percentage of human infections. In this work, we describe a rare case of central venous catheter-related Rhodotorula glutinis fungemia in a female patient with acute myelogenous leukemia in remission. The timely removal of central venous catheter was an essential element for overcoming this CVC-related Rhodotorula fungemia.
Topics: Central Venous Catheters; Device Removal; Female; Fungemia; Humans; Immunocompromised Host; Leukemia, Myeloid, Acute; Middle Aged; Rhodotorula
PubMed: 26329371
DOI: 10.3314/mmj.56.E17 -
Brazilian Journal of Microbiology :... Mar 2015In this study, we isolated and phenotypically identified 108 yeast strains from various clinical specimens collected from 100 hospitalized patients at three tertiary...
In this study, we isolated and phenotypically identified 108 yeast strains from various clinical specimens collected from 100 hospitalized patients at three tertiary hospitals in São Luís-Maranhão, Brazil, from July to December 2010. The isolates were analyzed for their susceptibility to four of the most widely used antifungal agents in the surveyed hospitals, amphotericin B, fluconazole, 5-flucytosine and voriconazole. The species identified were Candida albicans (41.4%), Candida tropicalis (30.1%), C. glabrata (7.4%), Candida parapsilosis (5.5%), Candida krusei (4.6%), Cryptococcus neoformans (4.6%), Trichosporon spp . (3.7%), Candida norvegensis (0.9%), Rhodotorula glutinis (0.9%) and Pichia farinosa (0.9%). A higher isolation rate was observed in the following clinical specimens: urine (54 isolates; 50%), respiratory tract samples (21 isolates; 19.4%) and blood (20 isolates; 18.6%). Candida albicans isolates were 100% sensitive to all antifungal agents tested, whereas Candida krusei and Crytococcus neoformans displayed intermediate resistance to 5-flucytosine, with Minimal Inhibitory Concentration (MIC) values of 8 mg/mL and 16 mg/mL, respectively. Both strains were also S-DD to fluconazole with an MIC of 16 mg/mL. C. tropicalis was resistant to 5-flucytosine with an MIC of 32 μg/mL. This study demonstrates the importance of identifying the yeast species involved in community and nosocomial infections.
Topics: Aged; Aged, 80 and over; Antifungal Agents; Brazil; Candida; Female; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Mycoses; Pichia; Prevalence; Rhodotorula; Tertiary Care Centers; Trichosporon
PubMed: 26221096
DOI: 10.1590/S1517-838246120120296 -
Microbial Cell Factories Jan 2015The aromatic compounds cinnamic acid (CA) and p-hydroxycinnamic acid (pHCA) are used as flavoring agents as well as precursors of chemicals. These compounds are present...
BACKGROUND
The aromatic compounds cinnamic acid (CA) and p-hydroxycinnamic acid (pHCA) are used as flavoring agents as well as precursors of chemicals. These compounds are present in plants at low concentrations, therefore, complex purification processes are usually required to extract the product. An alternative production method for these aromatic acids is based on the use of microbial strains modified by metabolic engineering. These biotechnological processes are usually based on the use of simple sugars like glucose as a raw material. However, sustainable production processes should preferably be based on the use of waste material such as lignocellulosic hydrolysates.
RESULTS
In this study, E. coli strains with active (W3110) and inactive phosphoenolpyruvate:sugar phosphotransferase system (PTS) (VH33) were engineered for CA and pHCA production by transforming them with plasmids expressing genes encoding phenylalanine/tyrosine ammonia lyase (PAL/TAL) enzymes from Rhodotorula glutinis or Arabidopsis thaliana as well as genes aroGfbr and tktA, encoding a feedback inhibition resistant version of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase and transketolase, respectively. The generated strains were evaluated in cultures with glucose, xylose or arabinose, as well as a simulated lignocellulosic hydrolysate containing a mixture of these three sugars plus acetate. Production of CA was detected in strains expressing PAL/TAL from A. thaliana, whereas both CA and pHCA accumulated in strains expressing the enzyme from R. glutinis. These experiments identified arabinose and W3110 expressing PAL/TAL from A. thaliana, aroGfbr and tktA as the carbon source/strain combination resulting in the best CA specific productivity and titer. To improve pHCA production, a mutant with inactive pheA gene was generated, causing an 8-fold increase in the yield of this aromatic acid from the sugars in a simulated hydrolysate.
CONCLUSIONS
In this study the quantitative contribution of active or inactive PTS as well as expression of PAL/TAL from R. glutinis or A. thaliana were determined for production performance of CA and pHCA when growing on carbon sources derived from lignocellulosic hydrolysates. These data will be a useful resource in efforts towards the development of sustainable technologies for the production of aromatic acids.
Topics: 3-Deoxy-7-Phosphoheptulonate Synthase; Ammonia-Lyases; Arabidopsis; Arabinose; Cinnamates; Coumaric Acids; Escherichia coli; Glucose; Kinetics; Lignin; Metabolic Engineering; Plant Proteins; Plasmids; Propionates; Rhodotorula; Transketolase; Xylose
PubMed: 25592545
DOI: 10.1186/s12934-014-0185-1 -
Biotechnology For Biofuels 2014Oleaginous microorganisms, such as bacterium, yeast and algal species, can represent an alternative oil source for biodiesel production. The composition of their...
BACKGROUND
Oleaginous microorganisms, such as bacterium, yeast and algal species, can represent an alternative oil source for biodiesel production. The composition of their accumulated lipid is similar to the lipid of an oleaginous plant with a predominance of unsaturated fatty acid. Moreover this alternative to conventional biodiesel production does not create competition for land use between food and oleo-chemical industry supplies. Despite this promising potential, development of microbial production processes are at an early stage. Nutritional limited conditions, such as nitrogen limitation, with an excess of carbon substrate is commonly used to induce lipid accumulation metabolism. Nitrogen limitation implies modification of the carbon-to-nitrogen ratio in culture medium, which impacts on carbon flow distribution in the metabolic network.
RESULTS
The goal of the present study is to improve our knowledge of carbon flow distribution in oleaginous yeast metabolism by focusing carbon distribution between carbohydrate and lipid pools in order to optimize microbial lipid production. The dynamic effects of limiting nitrogen consumption flux according to carbon flow were studied to trigger lipid accumulation in the oleaginous yeast Rhodotorula glutinis. With a decrease of the specific nitrogen consumption rate from 0.052 Nmol.CmolX (-1).h(-1) to 0.003 Nmol.CmolX (-1).h(-1), a short and transitory intracellular carbohydrate accumulation occurred before the lipid accumulation phase. This phenomenon was studied in fed-batch culture under optimal operating conditions, with a mineral medium and using glucose as carbon source. Two different strategies of decreasing nitrogen flow on carbohydrate accumulation were investigated: an instantaneous decrease and a progressive decrease of nitrogen flow.
CONCLUSIONS
Lipid production performance in these fed-batch culture strategies with R. glutinis were higher than those reported in the previous literature; the catalytic specific lipid production rate was 0.07 Cmollip.CmolX* (-1).h(-1). Experimental results suggested that carbohydrate accumulation was an intrinsic phenomenon connected to the limitation of growth by nitrogen when the nitrogen-to-carbon ratio in the feed flow was lower than 0.045 Nmol.Cmol(-1). Carbohydrate accumulation corresponded to a 440% increase of carbohydrate content. These results suggest that microbial lipid production can be optimized by culture strategy and that carbohydrate accumulation must be taken account for process design.
PubMed: 25520751
DOI: 10.1186/s13068-014-0164-0 -
Case Reports in Dermatological Medicine 2014Rhodotorula spp. have emerged as opportunistic pathogens, particularly in immunocompromised patients. The current study reports a case of onychomycosis caused by...
Rhodotorula spp. have emerged as opportunistic pathogens, particularly in immunocompromised patients. The current study reports a case of onychomycosis caused by Rhodotorula glutinis in a 74-year-old immunocompetent female. The causative agent was identified as R. glutinis based on the pinkish-orange color; mucoid-appearing yeast colonies on Sabouraud Dextrose Agar at 25°C; morphological evaluation in the Corn Meal-Tween 80 agar; observed oval/round budding yeast at 25°C for 72 hours; no observed pseudohyphae; positive urease activity at 25°C for 4 days; and assimilation features detected by API ID 32C kit and automated Vitek Yeast Biochemical Card 2 system. Antifungal susceptibility test results were as follows: amphotericin B (MIC = 0.5 µg/mL), fluconazole (MIC = 128 µg/mL), itraconazole (MIC = 0.125 µg/mL), voriconazole (MIC = 1 µg/mL), posaconazole (MIC = 0.5 µg/mL), anidulafungin (MIC = 0.5 µg/mL), and caspofungin (MIC = 16 µg/mL). Antifungal therapy was initiated with oral itraconazole at a dose of 400 mg/day; seven-day pulse therapy was planned at intervals of three weeks. Clinical recovery was observed in the clinical evaluation of the patient before the start of the third cure. Although R. glutinis has rarely been reported as the causative agent of onychomycosis, it should be considered.
PubMed: 25328721
DOI: 10.1155/2014/563261 -
PloS One 2014An efficient enzymatic process was developed to produce optically pure D-phenylalanine through asymmetric resolution of the racemic DL-phenylalanine using immobilized...
Efficient preparation of enantiopure D-phenylalanine through asymmetric resolution using immobilized phenylalanine ammonia-lyase from Rhodotorula glutinis JN-1 in a recirculating packed-bed reactor.
An efficient enzymatic process was developed to produce optically pure D-phenylalanine through asymmetric resolution of the racemic DL-phenylalanine using immobilized phenylalanine ammonia-lyase (RgPAL) from Rhodotorula glutinis JN-1. RgPAL was immobilized on a modified mesoporous silica support (MCM-41-NH-GA). The resulting MCM-41-NH-GA-RgPAL showed high activity and stability. The resolution efficiency using MCM-41-NH-GA-RgPAL in a recirculating packed-bed reactor (RPBR) was higher than that in a stirred-tank reactor. Under optimal operational conditions, the volumetric conversion rate of L-phenylalanine and the productivity of D-phenylalanine reached 96.7 mM h⁻¹ and 0.32 g L⁻¹ h⁻¹, respectively. The optical purity (eeD) of D-phenylalanine exceeded 99%. The RPBR ran continuously for 16 batches, the conversion ratio did not decrease. The reactor was scaled up 25-fold, and the productivity of D-phenylalanine (eeD>99%) in the scaled-up reactor reached 7.2 g L⁻¹ h⁻¹. These results suggest that the resolution process is an alternative method to produce highly pure D-phenylalanine.
Topics: Adsorption; Biocatalysis; Chemical Fractionation; Enzymes, Immobilized; Fungal Proteins; Kinetics; Phenylalanine; Phenylalanine Ammonia-Lyase; Rhodotorula; Silicon Dioxide; Stereoisomerism
PubMed: 25268937
DOI: 10.1371/journal.pone.0108586 -
Applied Microbiology and Biotechnology Oct 2014The environmental impact of agricultural waste from the processing of food and feed crops is an increasing concern worldwide. Concerted efforts are underway to develop... (Review)
Review
Sustainable conversion of coffee and other crop wastes to biofuels and bioproducts using coupled biochemical and thermochemical processes in a multi-stage biorefinery concept.
The environmental impact of agricultural waste from the processing of food and feed crops is an increasing concern worldwide. Concerted efforts are underway to develop sustainable practices for the disposal of residues from the processing of such crops as coffee, sugarcane, or corn. Coffee is crucial to the economies of many countries because its cultivation, processing, trading, and marketing provide employment for millions of people. In coffee-producing countries, improved technology for treatment of the significant amounts of coffee waste is critical to prevent ecological damage. This mini-review discusses a multi-stage biorefinery concept with the potential to convert waste produced at crop processing operations, such as coffee pulping stations, to valuable biofuels and bioproducts using biochemical and thermochemical conversion technologies. The initial bioconversion stage uses a mutant Kluyveromyces marxianus yeast strain to produce bioethanol from sugars. The resulting sugar-depleted solids (mostly protein) can be used in a second stage by the oleaginous yeast Yarrowia lipolytica to produce bio-based ammonia for fertilizer and are further degraded by Y. lipolytica proteases to peptides and free amino acids for animal feed. The lignocellulosic fraction can be ground and treated to release sugars for fermentation in a third stage by a recombinant cellulosic Saccharomyces cerevisiae, which can also be engineered to express valuable peptide products. The residual protein and lignin solids can be jet cooked and passed to a fourth-stage fermenter where Rhodotorula glutinis converts methane into isoprenoid intermediates. The residues can be combined and transferred into pyrocracking and hydroformylation reactions to convert ammonia, protein, isoprenes, lignins, and oils into renewable gas. Any remaining waste can be thermoconverted to biochar as a humus soil enhancer. The integration of multiple technologies for treatment of coffee waste has the potential to contribute to economic and environmental sustainability.
Topics: Biofuels; Biotechnology; Biotransformation; Coffee; Food Handling; Industrial Waste; Kluyveromyces; Rhodotorula; Saccharomyces cerevisiae; Saccharum; Yarrowia; Zea mays
PubMed: 25204861
DOI: 10.1007/s00253-014-5991-1 -
Journal of Applied Microbiology Sep 2014The focus of the research was to identify yeasts from barley kernels in order to study their folate production capability while maintaining high viscosity caused by...
AIMS
The focus of the research was to identify yeasts from barley kernels in order to study their folate production capability while maintaining high viscosity caused by soluble fibres in oat bran fermentation.
METHODS AND RESULTS
The 65 isolated yeasts were characterized by API carbohydrate utilization tests, and assays for extracellular enzyme activities were the following: amylase, beta-glucanase, cellulase or CMCase, lipase, protease and xylanase. Yeasts were identified by partial DNA sequencing of the 25S D1/D2 and ITS1-5.8S-ITS2 regions. They belonged to the genera Aureobasidium, Cryptococcus, Pseudozyma and Rhodotorula. Folate production was determined from supernatant and cells grown in a rich laboratory medium or directly from oat bran solution inoculated with the appropriate yeast. Food yeasts, Saccharomyces cerevisiae, Candida milleri, Kluyveromyces marxianus and Galactomyces geotrichum, were used for comparison. Most of the yeasts isolated from barley destroyed the solid, viscous structure of the oat bran solution, indicating that they degraded the viscosity-generating soluble fibres, considered to be nutritionally advantageous. The best folate producers were S. cerevisiae, followed by Pseudozyma sp., Rhodotorula glutinis and K. marxianus. The yeasts maintaining high viscosity were used together with lactic acid bacteria (LAB) Streptococcus thermophilus or Lactobacillus rhamnosus to ferment oat bran solution. None of the yeasts isolated from barley, contrary to S. cerevisiae and C. milleri, produced together with LAB significant amounts of folate.
CONCLUSIONS
Fermentative yeasts together with LAB are potential for use in developing novel high folate content healthy foods and snacks from oat bran.
SIGNIFICANCE AND IMPACT OF THE STUDY
High soluble fibre content and high natural folate content but low energy content food and snack products with pleasant fermentation aroma provide possibilities for new developments in the food industry.
Topics: Avena; Dietary Fiber; Fermentation; Folic Acid; Food Microbiology; Hordeum; Lacticaseibacillus rhamnosus; Streptococcus thermophilus; Yeasts
PubMed: 24916316
DOI: 10.1111/jam.12564 -
Biotechnology Reports (Amsterdam,... Sep 2014Phenylalanine ammonia-lyase (PAL) from JN-1 stereoselectively catalyzes the conversion of the l-phenylalanine into -cinnamic acid and ammonia, and was used in chiral...
Phenylalanine ammonia-lyase (PAL) from JN-1 stereoselectively catalyzes the conversion of the l-phenylalanine into -cinnamic acid and ammonia, and was used in chiral resolution of dl-phenylalanine to produce the d-phenylalanine under acidic condition. However, the optimum pH of PAL is 9 and the PAL exhibits low catalytic efficiency at acidic side. Therefore, a mutant PAL with a lower optimum pH is expected. Based on catalytic mechanism and structure analysis, we constructed a mutant PAL-Q137E by site-directed mutagenesis, and found that this mutant had an extended optimum pH 7-9 with activity of 1.8-fold higher than that of the wild type at pH 7. As revealed by Friedel-Crafts-type mechanism of PAL, the improvement of the PAL-Q137E might be due to the negative charge of Glu137 which could stabilize the intermediate transition states through electrostatic interaction. The PAL-Q137E mutant was used to resolve the racemic dl-phenylalanine, and the conversion rate and the value of d-phenylalanine using PAL-Q137E at pH 7 were increased by 29% and 48%, and achieved 93% and 86%, respectively. This work provides an effective strategy to shift the optimum pH which is favorable to further applications of PAL.
PubMed: 28626644
DOI: 10.1016/j.btre.2014.06.001