Identification Of Yeasts Research Articles

Identification and characterization of yeasts isolated from the South Shetland Islands and the Antarctic Peninsula

Antarctica is considered one of the most extreme environments on Earth because of its low temperatures, dryness, high incidence of solar radiation and low nutrient availability. Nevertheless, microorganisms including yeast have successfully colonized Antarctica; however, little is known about Antarctic yeast. In this study, cultivable yeast from soil samples collected from several islands of the South Shetland archipelago and Antarctic Peninsula were identified and characterized at different levels. Most yeasts were psychrotolerant and belonged to eleven genera, with the majority belonging to the Cryptococcus genus. Most yeasts were able to oxidize dextrin, α-d-glucose, sucrose and d-trehalose and to assimilate turanose, d-xylose, dextrin, d-trehalose, α-d-glucose and salicin. Evaluation of twelve hydrolytic enzymes revealed that yeast isolates displayed four to seven different enzyme activities, with lipase, alkaline phosphatase and invertase activities being observed in the majority of isolates. The isolates identified as Cryptococcus gastricus, Cryptococcus victoriae, Cryptococcus gilvencens, Leucosporidium sp. and Rhodotorula mucilaginosa displayed toxicity against other yeast isolates via the secretion of a protein factor. These results reflect the adaptation of yeast to their environment. The yeasts identified in this study have the potential for use as a biosource for the production of enzymes for industrial applications that require high enzyme activities at low temperatures.

Yeast Biodiversity from DOQ Priorat Uninoculated Fermentations.

Climate, soil, and grape varieties are the primary characteristics of terroir and lead to the definition of various appellations of origin. However, the microbiota associated with grapes are also affected by these conditions and can leave a footprint in a wine that will be part of the characteristics of terroir. Thus, a description of the yeast microbiota within a vineyard is of interest not only to provide a better understanding of the winemaking process, but also to understand the source of microorganisms that maintain a microbial footprint in wine from the examined vineyard. In this study, two typical grape varieties, Grenache and Carignan, have been sampled from four different vineyards in the DOQ Priorat winegrowing region. Afterward, eight spontaneous alcoholic fermentations containing only grapes from one sampling point and of one variety were conducted at laboratory scale. The fermentation kinetics and yeast population dynamics within each fermentation experiment were evaluated. Yeast identification was performed by RFLP-PCR of the 5.8S-ITS region and by sequencing D1/D2 of the 26S rRNA gene of the isolates. The fermentation kinetics did not indicate clear differences between the two varieties of grapes or among vineyards. Approximately 1,400 isolates were identified, exhibiting high species richness in some fermentations. Of all the isolates studied, approximately 60% belong to the genus Hanseniaspora, 16% to Saccharomyces, and 11% to Candida. Other minor genera, such as Hansenula, Issatchenkia, Kluyveromyces, Saccharomycodes, and Zygosaccharomyces, were also found. The distribution of the identified yeast throughout the fermentation process was studied, and Saccharomyces cerevisiae was found to be present mainly at the end of the fermentation process, while Aureobasidium pullulans was isolated primarily during the first days of fermentation in three of the eight spontaneous fermentations. This work highlights the complexity and diversity of the vineyard ecosystem, which contains yeasts from different species. The description of this yeast diversity will lead to the selection of native microbiota that can be used to produce quality wines with the characteristics of the Priorat.

Epidemiology and antifungal susceptibility of Candida species in a tertiary care hospital, Kolkata, India.

Background and Purpose:The incidence of fungal infection as well as candidemia has increased significantly, contributing to morbidity and mortality in the developed countries. The alarming increase in infections with multidrug resistant bacteria is due to overuse of a broad spectrum antimicrobials, which leads to over growth of Candida spp.; thus, enhancing its opportunity to cause the disease. A shift has been observed in the relative frequency of each Candida spp. Antifungal agents available for the treatment of systemic and invasive candidiasis are restricted to polyenes, allylamines, azoles, and the recent echinocandin class of molecules. In the past few decades, the incidence of resistance to antifungal treatment of Candida spp. has increased rapidly, which is of serious concern for healthcare professionals. Studies on prevalence of infections and antifungal susceptibility testing can help with deciding on clinical strategies to manage this problem. Herein, we aimed to identify the epidemiology of Candida spp. among blood culture isolates and to investigate the susceptibility pattern of these species to antifungal agents.Materials and Methods: Candida spp. were isolated from blood cultures from 70 patients in a tertiary care hospital, Kolkata, India. The growth of Candida spp. on sabouraud dextrose agar was confirmed by Gram staining, where gram-positive budding fungal cells were observed. The species identification as well as antifungal susceptibility testing were performed with VITEK 2 compact automated system using VITEK-2 cards for identification of yeast and yeast-like organisms) ID-YST card). Antifungal susceptibility testing was carried out with VITEK 2 fungal susceptibility card (AST-YS07 kit). Results:Out of 70 samples, Candida albicans were isolated from 34 (%48.57) samples. The remaining 36 (%51.43) were non-albicans Candida ) NAC). Out of 34 C. Albicans, antifungal susceptiblity was detected in 28 isolates, all of which were sensitive to fluconazole (FLC .( Resistance to amphotericine B) AMP), flucytosine (5FC), voriconazole (VRC), and itraconazole (ITC) was observed in, %44.12 , %52.94 , %8.82 and %17.65 of the cases, respectively. For other Candida spp. (other than C. Albicans ,( antifungal susceptibility was evaluated for 36 isolates, among which resistance to AMP, FLC , 5FC, VRC , and ITC was found in, %30.56 , %61.11 , %33.33 , %19.44 and %38.89 cases, respectively.Conclusion:Species-level identification of Candida and their antifungal sensitivity testing should to be performed to achieve better clinical result and to select an appropriate and effective antifungal therapy. High resistance to antifungal agents is an alarming sign to the healthcare professionals.

Identification and characterization of yeasts isolated from sedimentary rocks of Union Glacier at the Antarctica.

Thestudy of the yeasts that inhabit cold environments, suchas Antarctica, is an active field of investigation oriented toward understanding their ecological roles in these ecosystems. In a great part, the interest in cold-adapted yeasts is due to several industrial and biotechnological applications that have been described for them. The aim of this work was to isolate and identify yeasts from sedimentary rock samples collected at the Union Glacier, Antarctica. Furthermore, the yeasts were physiologically characterized, including the production of metabolites of biotechnological interest. The yeasts isolated that were identified at the molecular level belonged to genera Collophora (1 isolate), Cryptococcus (2 isolates), Sporidiobolus (4 isolates), Sporobolomyces (1 isolate) and Torrubiella (2 isolates). The majority of yeasts were basidiomycetous and psychrotolerant. By cross-test assays for anti-yeast activity, it was determined that Collophora sp., Sporidiobolus salmonicolor, and Sporobolomyces roseus secreted a protein factor that kills Sporidiobolus metaroseus. The colored yeasts Sp. salmonicolor, Sp. metaroseus and Collophora sp. produced several carotenoid pigments that were identified as 2,3 dihydroxy-γ-carotene, -carotene, 4-ketotorulene, torulene β-cryptoxanthin and spirilloxanthin. Concerning analysis of mycosporines, these metabolites were only found in the yeasts Torrubiella sp. and Cryptococcus sp. T11-10-1. Furthermore, the yeasts were evaluated for the production of extracellular hydrolytic activities. Of the twelve activities analyzed, alkaline phosphatase, invertase, gelatinase, cellulase, amylase, and protease enzyme activities were detected. The yeasts Cryptococcus sp. T11-10-1 and Sporidiobolus metaroseus showed the highest number of different enzyme activities.

English

“Rabile” is dried yeast harvested from Sorghum beer, used as a traditional starter culture but more especially as ingredient in sauce and food cooking in Burkina Faso. The present study aimed to isolate and identify indigenous yeast flora of “Rabile”. Standard microbiological process was carried out to value and isolate yeast in different samples of “Rabile” coming from four localities of Burkina Faso. Phenotypical method and molecular method (PCR and RFLP) were used for yeast strains characterization and identification. The results showed that yeast counts ranged from 9.49 to 10.35 log cfu/g of “Rabile”. A total of twenty yeast strains were isolated. Based on phenotypical characters three genera were detected: Candida (40%), Saccharomyces (35%) and Rhodotorula (25%). Molecular identification revealed two specific strains among yeasts isolated as S. cerevisiae with a frequency of 35% and R. mucilaginosa with a frequency of 25%. This data highlights the diversity of indigenous yeast flora of “Rabile”. Key words: Rabile, yeast, polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), traditional starter culture.

Enumeration and rapid identification of yeasts during extraction processes of extra virgin olive oil in Tuscany.

The aim of this study was to evaluate the occurrence of yeast populations during different olive oil extraction processes, carried out in three consecutive years in Tuscany (Italy), by analysing crushed pastes, kneaded pastes, oil from decanter and pomaces. The results showed yeast concentrations ranging between 10(3) and 10(5)CFU/g or per mL. Seventeen dominant yeast species were identified by random amplified polymorphic DNA with primer M13 and their identification was confirmed by restriction fragments length polymorphism of ribosomal internal transcribed spacer and sequencing rRNA genes. The isolation frequencies of each species in the collected samples pointed out that the occurrence of the various yeast species in olive oil extraction process was dependent not only on the yeasts contaminating the olives but also on the yeasts colonizing the plant for oil extraction. In fact, eleven dominant yeast species were detected from the washed olives, but only three of them were also found in oil samples at significant isolation frequency. On the contrary, the most abundant species in oil samples, Yamadazyma terventina, did not occur in washed olive samples. These findings suggest a phenomenon of contamination of the plant for oil extraction that selects some yeast species that could affect the quality of olive oil.

Sequencer-Based Capillary Gel Electrophoresis (SCGE) Targeting the rDNA Internal Transcribed Spacer (ITS) Regions for Accurate Identification of Clinically Important Yeast Species.

Accurate species identification of Candida, Cryptococcus, Trichosporon and other yeast pathogens is important for clinical management. In the present study, we developed and evaluated a yeast species identification scheme by determining the rDNA internal transcribed spacer (ITS) region length types (LTs) using a sequencer-based capillary gel electrophoresis (SCGE) approach. A total of 156 yeast isolates encompassing 32 species were first used to establish a reference SCGE ITS LT database. Evaluation of the ITS LT database was then performed on (i) a separate set of (n = 97) clinical isolates by SCGE, and (ii) 41 isolates of 41 additional yeast species from GenBank by in silico analysis. Of 156 isolates used to build the reference database, 41 ITS LTs were identified, which correctly identified 29 of the 32 (90.6%) species, with the exception of Trichosporon asahii, Trichosporon japonicum and Trichosporon asteroides. In addition, eight of the 32 species revealed different electropherograms and were subtyped into 2–3 different ITS LTs each. Of the 97 test isolates used to evaluate the ITS LT scheme, 96 (99.0%) were correctly identified to species level, with the remaining isolate having a novel ITS LT. Of the additional 41 isolates for in silico analysis, none was misidentified by the ITS LT database except for Trichosporon mucoides whose ITS LT profile was identical to that of Trichosporon dermatis. In conclusion, yeast identification by the present SCGE ITS LT assay is a fast, reproducible and accurate alternative for the identification of clinically important yeasts with the exception of Trichosporon species.

MP24-03 DIRECT DETECTION OF URINARY TRACT INFECTION FROM URINE SAMPLES USING MATRIX-ASSISTED LASER DESORPTION IONIZATION-TIME OF FLIGHT MASS SPECTROMETRY

INTRODUCTION AND OBJECTIVES: Traditionally, the microbiological confirmation of urinary tract infection (UTI) takes 2-3 days. Before the results are available, clinicians initiate treatment with antibiotics. These antibiotics are in many cases unnecessary, inefficient or cover a wider spectrum of microorganism than necessary and as results, the antibiotics resistance bacteria may be possible to produce. Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) becomes a rapid tool of the identification of bacteria and yeast. Thus, we collected urine specimens and compared between the results of conventional confirmation and these of directly identification by MALDI-TOF MS. METHODS: Urine samples were gathered from patients with UTI symptoms processed by conventional culture between January and September 2015 in Kobe University Hospital. These specimens grow in culture and analyzed the conventional confirmation and MALDI-TOF MS identification by Vitek MS system (bioM erieux). According to the manufacture, a score 2.0 indicated species identification, a score between 1.7 to 2.0 indicated genus identification and a score of < 1.7 indicates no identification. RESULTS: We tested these specimens [gram positive rods (GPR): 3.48 %, gram positive cocci (GPC): 33.7 %, gram negative rods (GNR): 59.3 % and Candida species: 3.52 %] isolated by conventional confirmation. The bacteria isolated directly by MALDI-TOF MS ( 2.0) were 66.7 % of GPR, 24.1% of GPC, 70.6% of GNR and no Candida species, and the bacteria ( 1.7) were 66.7 % of GPR, 44.8 % of GPC, 88.2 % of GNR and none of Candida species from urine samples. The most relevant bacteria was Escherichia coli (34.9 %), followed by Staphylococcus aureus (8.14 %) and Staphylococcus epidermidis (8.14 %). CONCLUSIONS: MALDI-TOF MS showed high rate of accuracy about 90% for the identification of GNR, but not GPR, GPC and Yeast. This strategy could become a rapid (15 minutes per sample) and accurate diagnostic method of especially in GNR-causing UTI so far and further improvement is necessary for application to GPR, GPC and Yeast by for instance revised condition setting. This may accomplish a strong possibility to improve the adequacy of UTI treatment in terms of reducing the time of empiric antibiotic treatment or allowing for the earlier withdrawal of unnecessary antibiotics.

Isolation and identification of yeasts along wastewater treatment lines at Zagazig plant

Isolation and identification of yeasts along wastewater treatment lines at Zagazig plant

The Isolation and Identification of Stress Tolerance Ethanol-fermenting Yeasts from Mozzarella Cheese Whey

Bioethanol conversions has long been considered as a possible solution for whey utilization. The existence of wild ethanol-fermenting yeasts that able to hydrolyze lactose become an important thing. Aims of the research was to isolate and identified the potential ethanol-fermenting yeasts from mozzarella cheese whey. Research done experimentally and analyzed descriptively. Yeast candidates isolated from mozarella cheese whey with pour plate method and purified on Potato Dextrose Agar (PDA) with the addition of 3% Yeast Extract and 10 ppm of Amoxycillin. The candidates were tested to stress tolerance towards various sugar and ethanol contents. Ethanol-fermenting yeast candidates tested in converting whey into bioethanol by inoculating 2% isolates into mozzarella cheese whey and incubated in room temperature (26-28°C) for 48 hours, then the ethanol contents tested by Gas Chromatography. The isolate that gave the highest ethanol contents identified using RapID Yeast Plus System. Results showed that there are 5.8 x 105 cfu/ml yeasts population in mozzarella cheese whey with four isolates that has different macroscopic character. Four candidate showed endurance towards 30% sugar and 20% ethanol contents and isolate W2 chosen as best isolate that produce the highest ethanol contents of 1,515.973 ppm. RapID Yeast Plus System has identified the isolate W2 has 96.43% similarity with Candida lambica .

Non-albicans Candida in Neonatal Septicemia - An emerging clinical entity

Background:- Over the past two decades the frequency of invasive mycosis in neonates has increased significantly. Candida species account for a significant percentage of all neonatal bloodstream infections and recently non-albicans Candida (NAC) have emerged as important opportunistic pathogens, notably Candida tropicalis , C. parapsilosis, C. krusei, and C. glabrata. Aims: This study was undertaken to know the distribution and antifungal susceptibility pattern of Candida species in neonatal septicemia cases. Materials and Methods: In a prospective analysis blood samples from 350 clinically suspected cases of neonatal septicaemia were collected aseptically. Only those which yielded pure growth of Candida spp. were included in the study. Identification of Candida species as well as antifungal sensitivity testing was performed with Vitek2 Compact (Biomerieux France) using vitek 2 cards for identification of yeast and yeast like organisms (ID-YST cards). Results: Isolation rate of Candida from neonatal septicemia cases was 10%. Most common isolate was C . tropicalis (57.14%), followed by C . albicans (17.1%), C . krusei (17.1%), and C . guillermondii (5.7% ) . Low birth weight and previous antibiotic prophylaxis were the main risk factors found in 100% cases. 62.85% candida isolates were sensitive to fluconazole whereas sensitivity to amphotericin B was 94.28% Conclusion: Non albicans Candida has emerged as an important cause of neonatal septicemia. Therefore speciation & antifungal susceptibility is a must in management of neonatal candidemia cases.

English

Thermotolerant yeasts, which are expected to be applicable for high-temperature fermentation as an economical process, were isolated from four provinces in Laos. Of these yeasts, five isolates exhibited stronger fermentation abilities in a 16% sugars-containing medium of glucose, sucrose, sugarcane or molasses at 40°C than that of Kluyveromyces marxianus DMKU 3-1042, one of the most thermotolerant and efficient yeasts isolated previously in Thailand. One of the five strains, BUNL-17, exhibited the highest ethanol fermentation performance at 45°C. Yeast identification was achieved by whole-cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) analysis as well as by nucleotide sequencing of the D1/D2 domain of the large subunit rRNA gene, revealing that the isolated strains can be categorized into Pichia kudriavzevii, Cyberlindnera rhodanensis and K. marxianus and that all of the five strains are K. marxianus. The results of this study showed that the former analysis is much faster than the latter and reliable and equivalent to the latter. Key words: Ethanol fermentation, thermotolerant yeast, Kluyveromyces marxianus.

Comparative lipid production by oleaginous yeasts in hydrolyzates of lignocellulosic biomass and process strategy for high titers.

Oleaginous yeasts can convert sugars to lipids with fatty acid profiles similar to those of vegetable oils, making them attractive for production of biodiesel. Lignocellulosic biomass is an attractive source of sugars for yeast lipid production because it is abundant, potentially low cost, and renewable. However, lignocellulosic hydrolyzates are laden with byproducts which inhibit microbial growth and metabolism. With the goal of identifying oleaginous yeast strains able to convert plant biomass to lipids, we screened 32 strains from the ARS Culture Collection, Peoria, IL to identify four robust strains able to produce high lipid concentrations from both acid and base-pretreated biomass. The screening was arranged in two tiers using undetoxified enzyme hydrolyzates of ammonia fiber expansion (AFEX)-pretreated cornstover as the primary screening medium and acid-pretreated switch grass as the secondary screening medium applied to strains passing the primary screen. Hydrolyzates were prepared at ∼18-20% solids loading to provide ∼110 g/L sugars at ∼56:39:5 mass ratio glucose:xylose:arabinose. A two stage process boosting the molar C:N ratio from 60 to well above 400 in undetoxified switchgrass hydrolyzate was optimized with respect to nitrogen source, C:N, and carbon loading. Using this process three strains were able to consume acetic acid and nearly all available sugars to accumulate 50-65% of cell biomass as lipid (w/w), to produce 25-30 g/L lipid at 0.12-0.22 g/L/h and 0.13-0.15 g/g or 39-45% of the theoretical yield at pH 6 and 7, a performance unprecedented in lignocellulosic hydrolyzates. Three of the top strains have not previously been reported for the bioconversion of lignocellulose to lipids. The successful identification and development of top-performing lipid-producing yeast in lignocellulose hydrolyzates is expected to advance the economic feasibility of high quality biodiesel and jet fuels from renewable biomass, expanding the market potential for lignocellulose-derived fuels beyond ethanol for automobiles to the entire U.S. transportation market. Biotechnol. Bioeng. 2016;113: 1676-1690. © 2016 Wiley Periodicals, Inc.

Epidemiology of candidemia in neonatal intensive care units: a persistent public health problem.

Candidemia has become an increasingly important problem in infants hospitalized in the Neonatal Intensive Care Units (NICUs). Candida species are the third most common agents of late-onset infections in critically ill neonates and they are associated with high morbidity and mortality rates. In this study we evaluated the epidemiology of Candida bloodstream infections in the NICU of an Italian university hospital during a 15-year period. Our specific aims were to analyze the change in species distribution and the vitro susceptibility of these yeasts to fluconazole (FCZ) and amphotericin B (AmB). A retrospective study of candidemia in the NICU of a university hospital in southern Italy, covering the years 2000-2014 was carried out. The isolates were identified using the VITEK2 yeast identification system and antifungal susceptibility was determined using the E-test method. Among the 57 patients with confirmed candidemia, 60% were males (n = 34 cases) and 82% (n = 47) had a gestational age of 24-32 weeks. Twenty-seven neonates (47%) had a very low birth weight (<1500 g), 20 (35%) an extremely low birth weight (<1000 g), and 10 (18%) a low birth weight (<2500 g). The most important potential risk factors were the placement of a central venous catheter, total parenteral nutrition, and endotracheal intubation (100%, each). Candida albicans was the most frequent yeast (47%), followed by Candida parapsilosis (44%). The proportion of Candida non-albicans increased slightly, from 46% in 2000-2004 to 71% in 2010-2014 (χ2 test for trend, p = 0.030). All isolates were susceptible to FCZ and AmB. The detection in this epidemiologic study of an increase in Candida non-albicans highlights the importance of correct species-level identification in the rapid diagnosis for an efficient treatment of candidemia. Knowledge of the local epidemiological trends in Candida species isolated in blood cultures will facilitate therapeutic decision-making.

Evaluation of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry in Identification of Nontuberculous Mycobacteria

Background/Aims: Species-level identification of nontuberculous mycobacteria (NTM) is important in making decisions about the necessity and choice of antimicrobial treatment. The reason is predictable clinical significance and the susceptibility profile of specific NTM species. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is recognized as a diagnostic tool for routine identification of bacteria and yeasts in the clinical laboratory based on protein fingerprint analysis. The aim of the study was to evaluate MALDI-TOF MS in the identification of NTM. Methods: A total of 25 NTM isolates from liquid cultures were identified with both polymerase chain reaction (PCR)-based hybridization assay and MALDI-TOF MS at the University Hospital Center Zagreb. Results: PCR-based hybridization assay identified 96% (24/25) and MALDI-TOF MS 80% (20/25) of tested NTM isolates. Five isolates with no reliable MALDI-TOF MS identification belonged to the Mycobacterium avium-intracellulare complex. Seventy percent (14/20) of NTM isolates successfully identified with MALDI-TOF MS had a score higher than 2.0, indicating reliable species identification. Conclusion: MALDI-TOF MS is a promising tool for the identification of NTM. With a further improvement of the protein extraction protocol, especially regarding the M. avium-intracellulare complex, MALDI-TOF MS could be an additional standard method for identification of NTM.

Yeast diversity in new, still fermenting wine "federweisser"

The aim of this study was to isolate and identify yeasts in different new wine "federweisser" samples. We collected the samples at the end of the August 2015 and in the middle of the September 2015. Used 15 new wine samples in this study (5 white and 10 red) were from the local Slovak winemakers. Irsai Oliver (3), Moravian Muscat (2), Agria/Turan (1), Dornfelder (3), Blue Frankish (3), Pinot Noir (1) and Saint Laurent (2). Three cultivation media were used for detection of yeasts in "federweisser" samples. Malt extract agar base (MEA), Wort agar (WA) and Wild yeast medium (WYM) were used for the cultivation of yeasts. Cultivation was performed by spread plate method. Ethanol/formic acid extraction procedure was used for preparation of samples. MALDI-TOF Mass Spectrometer (Microflex LT/SH) (Bruker Daltonics, Germany) was used for the identification of yeasts. We identified seven different strains of Saccharomyces cerevisiae (23; 70%), two strains of Kloeckera apiculata [teleomorph Hanseniaspora uvarum] (7; 21%), and one strain of Pichia kluyveri (1; 3%), Pichia occidentalis [anamorph Candida sorbosa] (1; 3%) and Metschnikowia pulcherrima (1; 3%) in 15 new wine "federweisser" samples. Saccharomyces cerevisiae was dominant species in each new wine sample, and formed creamy convex colonies with circular edge. Metschnikowia pulcherrima formed convex to pulvinate, circular white-pink colored colonies, Kloeckera apiculata formed flat, circular smooth colonies with turquoise center with gray edge, Pichia occidentalis formed irregular pulvinate light-cream colored colonies, and Pichia kluyveri formed turquoise, convex, undulate and smooth colonies on Malt extract agar base with bromocresol green.

Isolation, Characterization, and Identification of Yeasts Associated with Foods from Assiut City, Egypt

Isolation, Characterization, and Identification of Yeasts Associated with Foods from Assiut City, Egypt

Invasive Fungal Rhinosinusitis: An Observational Study in an Indian Tertiary Care Hospital

Invasive fungal rhinosinusitis (IFRS) is a challenging condition and the mortality of IFRS in immuno compromised patients is very high. 75 patients of suspected FRS were included to study the burden and the clinicopathological and mycological profile of invasive fungal rhinosinusitis (FRS) in these patients. The samples collected were exudate from nasal debri, discharge and intraoperative tissue sample and were subjected to direct microscopy to histopathological examination and direct microscopy (KOH and calcofluor white) and culture on Sabouraud dextrose agar. Identification of molds and yeasts were done by conventional methods. 25 cases were suspected to have IFRS were confirmed by microbiological and histo pathological examination, comprising 56% of AIFRS (acute IFRS), 36% CIFRS (chronic IFRS) and 8% CGFRS (chronic granulomatous FRS). Rhizopus arrhizus (64.2%) was the most common isolate followed by Aspergillus flavus (35.7%). Mucor species were solely isolated from AIFRS (14.3%). In CIFRS, Aspergillus flavus (44.4%) seemed to be the major isolate with Aspergillus niger, Alternaria spp., Penicillium spp. and Candida albicans. Necrosis of submucosa, bone, vascular tissue was seen in 96% of cases with aseptate hyphae in 78.5% AIFRS and 77.7% in CIFRS. Radiological features help in presumptive diagnosis of FRS. Direct microscopy along with culture conformation is important for diagnosis and early initiation of treatment.

Use of Wastewaters from Ethanol Distilleries and Glycerol Mixtures for Microbial Oils Production

Biodiesel has become more attractive in recent years because of its environmental benefits. One way to reduce the high cost of biodiesel is by lowering the cost of raw materials specially oils. Recently, much attention has been paid to the development of microbial oils through cultures of oleaginous microorganisms in inexpensive substrates as the wastewaters of some food industries and the crude glycerol from biodiesel production itself. Thus, cultivation of oleaginous yeasts in glycerol-based media is attracting great interest and natural biodiversity is increasingly explored to identify novel oleaginous species recycling this carbon source for growth and lipid production. Identification of oleaginous yeasts and the evaluation in glycerol and vinasse mixtures was employed to produce biomass enriched in microbial lipids and to remove nutrients from vinasse simultaneously. The fatty acid composition of the lipids was similar to that from plant oils and other microbial lipids therefore they can be used as raw material for feed additives and biodiesel production.

Isolation and Identification of Local Ethanol Tolerant Yeast Populating Distillation and Milling Sites in Nigeria

Two yeast strains referred to as OY and SY were isolated and characterised from local distillery and cereal milling sites. Isolation was done using potato dextrose media supplemented with 0.2% chloramphenicol. Morphological and biochemical results together with the rDNA internal transcribed spacer region (ITS) were identified as <i>Pichia kudriavzevii</i> strains GY1 and L9 respectively. OY and SY are ethanol tolerant strains, withstanding ethanol concentrations of up to 20% (v/v) in yeast extract, peptone, malt extract, glucose media. OY and SY displayed good growth in ethanol supplemented medium with pH ranging from 4.8-5.5 at 30°C. Growth measurements were determined by measuring optical density of the cells in broth using spectrophotometer at 570nm. The results obtained suggested that OY and SY demonstrated good parameters as ideal candidates for bioethanol production.