جستجوی مقالات مرتبط با کلیدواژه « مخمر » در نشریات گروه « زیست شناسی »

In recent years, the need for L-asparaginase in different industries has increased. L-asparaginase obtained from microorganisms is cost-effective, has no harmful effects on the environment, and improves the quality of products. In the present study, L-asparaginase-producing microorganisms were isolated and optimized from different sources, and selected strain enzymes were produced. L-asparaginase-producing yeasts were randomly isolated and purified from different parts of Isfahan. Strains were screened for L-asparaginase production. Then, the superior yeast strain with the highest enzymatic activity was selected for optimization. Under suitable pH, temperature, time, carbon source, and nitrogen source, multi-factor optimization was performed using response-level statistical software to investigate the simultaneous effect of several factors on production and the highest enzyme activity. In the present study, 5S2 yeast isolate led to the formation of the highest halo of L-asparaginase. This strain was first introduced as the L-asparaginase-producing strain and was registered in the NCBI database under Diutina mesorugosa strain SBG-IAUF-2 with access number MZ901211. Yeast 5S2 with enzyme activity equivalent to 1722.8 u / ml was selected as the selected strain for optimization. The results of multivariate optimization of enzyme activity showed that at pH 7, a concentration of 2% glucose as carbon source, the attention of 10% L-asparagine, a temperature of 35°C, and a time of 120 hours, there is the highest enzyme production activity and curve RSM is located in the optimization area. In the present study, after recording 5S2 yeast isolate for the first time as an L-asparaginase-producing strain in the NCBI database, extracellular L-asparaginase produced by the 5S2 yeast strain was introduced due to its high enzymatic activity as a potent strain in the production of L-asparaginase enzyme.

Oils extracted from microorganisms (SCO) are preferable to vegetable oils due to containing more gamma-linolenic acid, more stability against oxidation, and less content of residual pesticides. The oils can be used as dietary supplements. The aim of this study was molecular identification of lipid-producing yeasts and molds in soil and optimization of fat production by Candida glabrata using the Taguchi design.

Several yeasts and molds were isolated from the soil samples of groves and near oil change shops and restaurants. Molecular identification was performed by polymerase chain reaction (PCR). Among them, the highest lipid producers were selected and using the Taguchi design. The best conditions in terms of carbon and nitrogen sources as well as pH for maximum lipid production were determined. The fat obtained was examined by gas chromatography with a mass spectrometer detector (GC-MS).

Among the identified species, C. glabrata had the highest lipid production. Production of palmitoleic, palmitic, linoleic, linolenic, and stearic acid was proven in this study. Lipid production in C. glabrata and Mortierella alpina was 6.9 and10.8 grams per litre, respectively.

Due to the rapid reproduction in yeasts and their ability to produce fatty acids, C. glabrata is a suitable option for fat production.

Kombucha is a tea with a slightly sweet and sour taste. This drink is rich in acetic, gluconic and glucuronic acids and has a lower concentration of citric acid as well as a limited amount of ethanol and CO2. This article discusses the beneficial effects of kombucha, its chemical composition and metabolites from the fermentation process, as well as the properties of kombucha in particular as a natural probiotic compound. The purpose of this article is to introduce a natural food composition rich in organic matter and essential to increase human health.

This drink is prepared by fermenting Sweet tea with Scooby Carrier of microes. Kombucha is based on a variety of teas such as black tea, green tea or oolong. Usually a piece of polysaccharide containing microbes including Saccharomyces cerevisiae and Acetobacter xylinum is brewed in 150 g of tea with 5 to 15% sucrose and placed in the dark for 7 to 10 days. Next, the polysaccharide layer microbial colony is removed and the kombucha is ready to eat. The final product contains organic acids, vitamins, minerals and antimicrobial and antioxidant compounds. Lowering cholesterol and blood pressure, preventing cancer, improving liver function, immune system and gastrointestinal tract are some of the potentially beneficial effects of kombucha drink. Acetobacter, Glucobacter and Saccharomyces cerevisiae are the most important natural probiotics in this drink, which help protect human health by producing organic acids.

Nowadays, by diversifying the production of kombucha, the amounts of its useful metabolites such as vitamins, organic acids and antimicrobial and antioxidant compounds  can be optimized and used as a natural medicinal supplement.

Probiotics are living microorganisms that have an important role in prevention and treatment of diseases. The aim of this study was isolate yeast with probiotic properties due to the importance of probiotic yeasts. Sampling was performed from different parts of human skin. Growth ability of isolated yeast at concentrations of 0.3, 0.5 and 1% oxgall, 2, 4 and 6% NaCl, pHs of 2, 4, 5.8, 9 and 11 and temperature 37, 40 and 42°C were investigated. The activity of amylase, protease, pectinase, cellulase, lipase, urease, catalase, citratase and hemolysin was investigated. The yeast was able to grow in 0.3% oxgall, concentrations of 2, 4 and 6% NaCl, pHs of 2, 4, 5.8, 9 and 11 and also at a temperature of 37°C. The isolated yeast has the primary properties of probiotics and can be used in future studies.

The carotenoid-producing yeasts have a widespread distribiution  worldwide. However, isolation of carotenoid-producing yeasts with valuable astaxanthin have been only reported from limited areas and specific habitats. The aim of this study was to apply the multiple polymerase chain reaction method for faster molecular screening of isolates for the yeasts in the exudation sap from birch trees (Betula pendula Roth.) in Alborz Province of Iran with astaxanthin production capacity and toevaluate its efficiency.

This cross-sectional study was carried out by sampling in May 2018 from one of the natural habitats of birch trees Batula Pendula in Alborz Province, Iran. After isolation of yeasts using selected media and purification of yeast colonies with various pink to red colors, yeasts genomic nucleic acids were extracted and molecular screening for astaxanthin-producing detection of isolates was performed by multiple polymerase chain reaction (Multiplex-PCR).

Out of 42 pigmented colonies during sampling and isolation in one cross-sectional study, 23 pink to red colonies were evaluated by Multiplex-PCR method. Of these isolates, three were positive and the rest were negative. The results were validated by determining the ribosomal gene sequencing.

The present study demonstrates the specificity of the multiple polymerase chain     reaction method in fast and cost-effective molecular screening of astaxanthin-producing yeast   isolates and the applicability of this method to study other natural habitats of these yeasts.

Plants have been used as medicines in the treatment of diseases from the past to present. In this research, the anti-microbial effects of aqueous and methanolic extracts of Erythrostemon gilliesii were studied. For this purpose, fresh flowers were ground and then macerated in methanol 100% and water overnight. After the evaporation of solvents, anti-microbial activities of the concentrated extracts were evaluated by the well-diffusion method on Klebsiella pneumoniae, Pseudomonas aeroginosa, Methicilin resistance, Staphylococcus aureus, Bacillus subtilis and Candida albicans. The results showed that the extracts were effective on different bacteria and yeasts. In order to determine the minimum inhibitory concentration (MIC) and minimum biocidal concentration (MBC), anti-microbial tests were performed in micro-plates. Subsequently, the results indicated that the extracts were stable at different temperatures. The aqueous and methanolic extracts of the flowers of E. gilliesii had exhibited anti-microbial effects against important infectious microbes and could be introduced as an excellent source for anti-microbial agents.

Background & A portion of biodiversity and variability of life on earth belongs to the yeasts. The caroptenoid-producing yeasts are economically important and their distinct natural habitats are of interest. In this study, isolation and molecular identification of carotenoid-producing yeasts of the exudates of endangered birch trees (Betula pendula Roth.) at Marmisho in Northwest Iran were performed. Materials & This cross-sectional study carried out by sampling from exudates of birch trees (Betula pendula Roth.) at a natural habitat located in West Azerbaijan Province in the Northwest of Iran. Using selective media, the isolation of the yeasts was done. The screening was initially based on the color and shape of the colonies during one-month incubation along with simple rapid tests to check the existence of carotenoid pigments. Finally, the D1/D2 region rDNA sequencing was accomplished for 19 isolates. 19 out of 45 isolates with pink-red colonies were selected for ribosomal gene sequencing. Phylogenetic results showed that the carotenoid-producing yeasts are in the Basidiomycota division including Rhodotorula, Cystofilobasidium, Cystobasidium, Rhodosporidiobolus, Ustilentyloma, and Xanthophyllomyces.  The unique pattern of carotenogenic yeasts community at this ecological niche and placing in 6 genera with the capability to produce a variety of carotenoid structures indicate that the exudates of birch trees (Betula pendula Roth.) include a wide diversity for native carotenoid-producing yeasts. This study is the first report presenting the diversity of carotenoid-producing yeasts in the Northwest of Iran with a distinct consortium of native yeasts at this habitat.

Lipase is used in the production of foods, flavor enhancers, detergents, cosmetics and pharmaceuticals. A common impediment to the production of commercial enzymes is their low-stability aqueous solutions. In this study, the downstream process was investigated to obtain a stable spray-dried lipase powder of Yarrowia lipolytica. The enzyme solution samples were supplemented with different concentrations of Arabic gum and milk powder to spray-drying. Samples were dried in a pilot spray dryer at inlet and outlet temperatures of 175 and 85 °C, respectively, at a flow rate of 15 liters per hour. The best lipase powder obtained from spray-drying with 3% of Arabic gum and 9% of milk powder formulation as compared with other formulations. Results showed that spray-dried lipase powders of Y. lipolytica had a good yield suitable for various applications.

Saccharomyces yeast genus has a wide application in biotechnology that several studies on this subject are performed. They have also known as a dietary supplement in breeding all kinds of creatures in particular for aquatics. Species of this genus are considered as probiotics, as well as a lot of beneficial effects on growth are creatures and Yeasts can be cultured in a variety of waste and cheap substrates, including hydrocarbons and petroleum. So finding an Appropriate and inexpensive culture media for optimal growth of yeast is important. In the present study, along with the study of Saccharomyces species diversity as intestinal flora of domestic rainbow trout flora, optimum growth conditions the strains of Saccharomyces cerevisiae was studied in different culture media as YPD, YPAD, YPG, YPAC, and DM. This research not only emphasized the diversity of Saccharomyces cerevisiae strains as an intestinal flora in domestic fishes, but also revealed the optimum growth of yeasts in YPAD media.

​Microalgae with stores of carbohydrates are introduced as a promising energy resource to produce In this study, a mixed culture was used for reducing the processing costs. Afterward, nitrogen starvation strategy was used to increase the storage in The application of mixed cultures enhances the economic feasibility of the process due to the elimination of culture sterilization. After harvesting and drying enzymatic hydrolysis of microalgal biomass for extraction Afterward, the enzymatic hydrolysate of microalgal biomass (25, 50, 100g/L) underwent fermentation with Saccharomyces cerevisiae and kinetic models for fermentation were studied. The inhibition of glucose substrate and product was considered in the kinetic model. AQUASIM 2.0 software was used as a tool to simulate the fermentation process. The estimated values of the maximum specific growth rate (μ) Monod constant (Ks) to be 0.281h −1 1.8g/L, respectively. Also, the results indicate that the kinetic model predicted the behavior of the system well.

Reducing fossil fuels, increasing fuel prices and carbon dioxide emissions, and concern about climate change are encouraging factors for biofuels production. Microbial biofuels are liquid and gaseous fuels which produced by microorganisms. Bioethanol is a suitable alternative biofuel for petroleum based fuels. For the industrial and high-scale production of bioethanol, the first step is isolation of suitable yeast strain with high tolerance to ethanol and high-level ethanol production. Hence, the aim of this study was Isolation of industrial strain Saccharomyces cerevisiae with high tolerance to ethanol from Iran's alcohol manufactures. Sampling from several Iran's alcohol manufactures was carried out for the isolation of Saccharomyces cerevisiae with the highest ethanol production and tolerance. Selected yeast strain was examined by morphological, biochemical tests such as sugars fermentation, absorption of nitrogen compounds and carbon compounds, and also molecular test. The selected yeast strain produced 8% ethanol and tolerated 12% ethanol. The morphological, biochemical and molecular tests confirmed that the yeast strain is Saccharomyces cerevisiae, and this strain was named Saccharomyces cerevisiae Sahand 101. The isolated industrial yeast strain with the suitable characteristics in terms of ethanol production and tolerance to ethanol can be used for further studies and increase ethanol production by optimization methods at the level of flask and bioreactor.

These days, Scientsts search for cheap protein sources because of growthing of population.One of these sources is Single Cell Protein.This study deals with Single Cell Protein production process by Saccharomyces cerevisiae and Saccharomyces carlsbergensis .These yeast are known as the most ideal and practical eukaryotic microorganism in biological studies. In this survey we added the waste of Kilka fish meal factories (Stick water) in Mazandaran and analyzed physical and chemical factors in the lab.The yeast medium was YGB (Yest Extract Glucose Broth). It is used control medium and medium whitch has 50% and 100% Stick water in order to investigation of growthing yeast. Producted Organizem are analyzed for dry material percent,moisture,protein,ash and amino acid profile. In order to analyze of results, we used SPSS and ANOVA system. In this survey, the mount of Single Cell Protein production in Saccharomyces carlsbergensis was more than Saccharomyces cerevisiae. But we dident watch any obviously different between them.

In this study, the effects of different diets on growth rates of Gammarus Pontogammarous meoticus were determined. A biomass of 1.5 g Gammarus with an average length of 7 ± 0.25 mm was transferred to the glass aquaria with volume 900 cm3 (volume 2.5 l). The Gammarus were fed with diets include baked potato (treatment 1), 30 percent yeast and 70 percent potato, (treatment 2), 50 yeast percent and 50 percent potato (treatment 3), no feeding (treatment 4) at rate of 6 to 7 percent of total biomass for 45 days. Results showed that the total production rate (adult and baby), specific growth rate and population doubling time were significantly high in treatments 2 and 3(P > 0.05). The biomass and daily growth rate were significantly higher than yeast fed Gammarus (P> 0.05). Additionally Gammarus in treatment 3 had the highest food conversion ratio. The results of the present study showed that the administration of yeast in diet can improve Gammarus growth rate under culture conditions.

Yeasts are eukaryotic cells that are not only important in terms of economic, social and health matters but also have application in biotechnology, industry and production of enzymes, vaccines, food and some recombinant medicines. These single-cells are isolated from natural environment or as micro flora and fauna which is cultured lately in mass. Yeasts special privileges include: fast and high resistance to a wide range of different materials which has caused many applications in aquatic husbandry. Undoubtedly, high value of food and affordable financing in fish farming is considered. The molecular manipulations and yeast as well as enriching of these organisms could improve the quality of growth and survival of the fishes by these biotechnologic and valuable microorganism. Yeasts also have been suggested as a dietary supplement in laboratory studies, cultural and even human beings, for example, Saccharomyces cerevisiae is a useful yeast which frequently used in the food industry.

Mixed aerobic and anoxic conditions، in addition to substrate versatility، provide a wide range of microhabitats and niches for a large number of microbial species including bacterian yeasts and filamentous fungi. Among them، study of environmental yeast species، especially those producing secretory catabolic enzymes، can be of a great importance. After enrichment of water and soil samples and their cultivation on antibiotic supplemented YPG Agar، 46 isolates were obtained. Most of the isolates were capable of producing nucleases and sterases. Using cup plate method revealed that strains SA044 and SA006 were able to produce the greatest number of secretory enzymes. Production of at least one secretory amylase، protease، nuclease and lipase was recorded in one or both of these isolates. Production of secretory keratinase، cellulose، phytase، xylanase، chitinase and pectinase was not observed. Using molecular approach and phenotypic examinations، the isolates SA044 and SA006 were identified as Pseudozyma aphidis and Pseudozyma antarctica respectively.

In this study، production of single cell protein from viscera of some tuna fish was investigated. The used yeasts were consisting of Candida utilis، Saccharomyces cerevisiae، Rhodotorula glutinus. Examination was done two scale laboratory and fermentor (Continuous Stirred Tank Reactor). The used fermentor was Continues Stirred Tank Reactor (CSTR). The results showed that mean of crude protein (g/l) was 32-38. 5 and 37. 5- 45 for lab and fermentor scales respectively. Time of fermentation in lab and fermentor scales was 54h and 21h respectively. Growth of Candida utilis and value of crude protein were more than other used yeasts. Mean of protein، lipid، wet and ash in produced microbial protein were 75. 48%، 7. 05%، 4. 38% and 1. 08% respectively. The conclusion of this study showed that with optimizing of growth parameters for yeasts and also suitable fermentor can be produced SCP with high quality and can be used from this products as probiotic in animal feed.

Many microorganisms like fungi, bacteria and yeasts, have a natural ability to produce vitamins included vitamin B2 or riboflavin. In this regard, the present study was performed to isolation and screening for riboflavin producing yeasts from various sources of soil, leaf and fruit s. Materials and method s: samples of leaf, soil and fruits were prepared for the presence of yeasts and by its ability to produce riboflavin. After purification and enrichment of samples, in order to assay riboflavin production, spectrometry, thin layer chromatography and high performance liquid chromatography were used. Finally, the best selected isolate was identified using conventional morphological, biochemical and molecular techniques. In this study, 26 yeast strains were isolated from environmental samples, that 6 isolates showed the ability to produce riboflavin. Identification results of the best selected isolate by biochemical and phenotypic characteristics revealed that this isolate is related to Clavispora lusitaniae and considering isolation of it from nectarine, has named it Clavispora lusitaniae strain N3 (Gene accession no: JQ586258). Discussion and Although only one of the six producing strains was studied and identified, observation of ability to produce among 23% of strains showed necessity for further investigation. And according to the result of absence of viewing report about production by investigated strain, it can be said that Iran has potentiality for isolation of yeasts and is capable of producing riboflavin.