Browsing by Author "Eltem, R"

Now showing 1 - 7 of 7
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    ENHANCEMENT OF SOLID STATE FERMENTATION FOR PRODUCTION OF PENICILLIN G ON SUGAR BEET PULP
    Taskin, E; Eltem, R; Soyak, E
    In this study, two local strains of Penicillium chrysogenum named EGEK458 and EGEK469 were selected for enhancement of Penicillin G (PenG) production under solid state fermentation (SSF) conditions. These two strains were selected among seven strains according to their fermentation yields for PenG production during previous tests under submerged fermentation conditions. Sugar beet pulp, an agro-industrial residue of the sugar industry, was used as an inert support for the first time in PenG production under SSF. In order to enhance the production of PenG, two points of moisture level and three concentration values of nutrients (impregnated in solid support), which are the key parameters in production of PenG, were compared. As the yields from solid and submerged fermentation were compared, 570U/g of PenG - almost 15 times higher quantities of its production vs. submerged conditions - were obtained under SSF conditions in 50 hours by the strain EGEK458. The conditions for the enhanced production of PenG were 65% moisture content with a four-fold concentrated nutrients impregnated solid support.
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    BIODIVERSITY AND FLORA OF MICROFUNGI FROM SULTANA-TYPE VINEYARD SOILS IN TURKEY
    Eltem, R; Taskin, E; Pazarbasi, S
    In this study, the culturable microfungi flora of vineyard soils belonging to Manisa and Izmir provinces (Turkey) were investigated quantitatively and qualitatively (species composition, diversity characteristics, such as species richness, evenness). Soil samples of 62 sultana-type vineyards from five locations (Alasehir, Manisa 1, Manisa 11, Manisa III and Izmir) were collected using the Brown's technique. The soil dilution technique was used for microfungi isolation. The mean microfungi number of I fresh soil was counted to be 71 000 colony forming units (CFUs). A total of 66 species and 3 varieties belonging to 16 genera were encountered including Aspergillus, Penicillium, Cladosporium, Alternaria, Rhjzopus, Trichoderma, Chaetomium, Chrysosporium, Dreschlera, Glomerularia, Gliocladium, Fusarium, Fusidium, Nectria, Spicaria, and Rhizomucor. Members of Aspergillus section Nigri, generally known as black Aspergilli, dominated all locations and their incidence among all isolated fungi was 80.4%. Aspergillus aculeatus was the most encountered species with 100% ratio. It was followed by A. foetidus var. pallidus with 93.3%, and A. awamori with 73.3%. The highest microfungal diversity was found in location Manisa 11 (station Saruhanh) with indexes for biodiversity as Shannon (H) 3.28, Simpson's (D) 0.93 and Evenness (J) 0.96. This is the first extensive study carried out on biodiversity and microfunci flora of vineyard soils in Turkey.
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    The enhancement of polygalacturonase and polymethylgalacturonase production on solid-state conditions by Aspergillus foetidus
    Taskin, E; Eltem, R
    In this study, a previously isolated strain of Aspergillus foetidus Ege-K-635 producing highly active polygalacturonase and polymethylgalacturonase was used for improvement of enzyme production using solid-state conditions. To enhance the enzyme yield, the mixture of two substrates such as sugar beet pulp and wheat bran, having different ratios of carbon-nitrogen and moisture levels was used. Further the effect of the amount of inoculum was investigated. Physical parameters for the highest polygalacturonase and polymethylgalacturonase production under solid state conditions were determined on wheat bran: the sugar beet pulp (1:2) mixture substrate composition having a 31:1 carbon-nitrogen ratio with 8 x 10(6) spores/gram of dry substrate as the inoculum amount. Adequate moisture levels were 75% and 70% for polygalacturonase and polymethylgalacturonase, respectively. Under these conditions, the highest activities obtained were 385 +/- 12.3 Ug(-1) on the third day for polygalacturonase and 18.3 +/- 3.2 Ug(-1) on the second day for polymethylgalacturonase.
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    Modification of surface morphology of UHMWPE for biomedical implants
    Oztarhan, A; Urkac, ES; Kaya, N; Yenigul, M; Tihminlioglu, F; Ezdesir, A; Zimmerman, R; Budak, S; Muntele, C; Chhay, B; Ila, D; Oks, E; Nikolaev, A; Tek, Z; Eltem, R
    Ultra High Molecular Weight Polyethylene (UHMWPE) samples were implanted with metal and metal-gas hybrid ions (Ag, Ag+N, C+H, C+H+Ar, Ti+O) by using improved MEVVA Ion implantation technique [1,2]. An extraction voltage of 30 kV and influence of 1017 ions/cm2 were attempted in this experiment. to change their surface morphologies in order to understand the effect of ion implantation on the surface properties of UHMWPEs. Characterizations of the implanted samples with RBS, ATR - FTIR, spectra were compared with the un-implanted ones. Implanted and unimplanted samples were also thermally characterized by TGA and DSC. It was generally observed that C-H bond concentration seemed to be decreasing with ion implantation and the results indicated that the chain structure of UHMWPE were changed and crosslink density and polymer crystallinity were increased compared to unimplanted ones resulting in increased hardness. It was also observed that nano size cracks (approx. 10nm) were significantly disappeared after Ag implantation, which also has an improved antibacterial effect. Contact angle measurements showed that wettability of samples increased with ion implantation. Results showed that metal and metal+gas hybrid ion implantation could be an effective way to improve the surface properties of UHMWPE to be used in hip and knee prosthesis.
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    Effect of yearly conditions and management practices on ochratoxin A production in Sultana Seedless vineyards
    Meyvaci, KB; Aksoy, U; Eltem, R; Altindisli, A; Askun, T; Taskin, E
    Sun drying of seedless grapes (Vitis vinifera cv. Sultanina) is widely practised in the western Aegean Region providing Turkey with a significant share in the world trade of sultanas. Research was initiated in 1998 to determine the incidence of ochratoxin A (OTA), to identify the major factors resulting in contamination and to develop techniques to reduce or prevent contamination. This paper assesses OTA formation in five experimental vineyards located in Manisa province of Turkey between 1998 and 2003. The cultural practices recorded were tillage (type and timing), fertilisation, plant protection, irrigation, trellising, pruning, GA(3) application, harvest maturity and date, and drying practices (type of drying yard, dipping into alkaline solution, length of drying period). In the experimental vineyards, no OTA was found at veraison. OTA levels in grapes harvested at fresh maturity ranged between
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    Screening of Aspergillus strains isolated from vineyards for pectinase production
    Taskin, E; Eltem, R; da Silva, ES; de Souza, JVB
    Pectin is present in walls of plant cells. Pectinases are important for food and chemical industry that processes plant material, and also juice, textile and vine industry uses pectinases. They are able to modify and cause depolymerization in pectin chains. Fungi from genus Aspergillus are one of the most important sources of these enzymes. Vineyards contain plant material in decomposition and are a special place for pectinase producers. Many works screening pectinase producers were described in literature. However, better producers have been continuously found. This paper describes a screening of Aspergillus strains isolated from vineyards for pectinase production. The fungi strains (262) were evaluated in the screening methodology that studied the diameter of the pectin hydrolysis halo and the size of the colony in an agar culture media containing pectin as the sole carbon source. Four strains were selected for fermentation experiments. Aspergillus foetidus var. pallidus Ege-K-730 and Aspergillus aculeatus Ege-K-355 presented the highest pectinase production ratio, and Aspergillus foetidus var. pallidus K-635 and Aspergillus aculeatus K-398 presented the highest colony diameter. Aspergillus carbonarius CFTRI 1047 was used as a reference strain. In submerged fermentation (SbF), the strains Ege-K-730, Ege-K-355, Ege-K-635 and CFTRI 1047 produced the highest PG (polygalacturonase) and PMG (polymethylgalacturonase) levels, however, Ege-K-730 was the faster producer. In solid state fermentation (SSF), the strains Ege-K-730, Ege-K-635, Ege-K-398 and CFTRI 1047 produced the highest PG and PMG levels. In the experimental conditions, SSF was better than SbF for pectinase production.
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    Determination of antifungal efficiency of some fungicides and secondary metabolites of Trichoderma species against Botrytis cinerea
    Savas, NG; Yildiz, M; Eltem, R; Ozkale, E
    Aim: The present study aimed to investigate the antifungal effects of fenhexamid, cyprodinil+fludioxanil, Bacillus subtilis QST 713, Trichoderma secondary metabolites (EGE-K-38 and EGE-K-71) on 6 isolates of necrotrophic fungi (Botrytis cinerea) under in-vitro conditions. Methodology: the effects of volatile compounds produced by Trichoderma in culture media against Botrytis cinerea isolates. For non-volatile and volatile metabolites, measurements for growth inhibition were made with the mixture of filter sterilized liquid medium of Trichoderma and potato dextrose agar. The fungicidal effects of these non-volatile metabolites and fungicides were first evaluated according to the effective concentration (EC50) data of growing mycelium inhibition of disease agents. Results: the lowest fungicidal activity was determined as fenhexamide, which seems to have the lowest EC50 value of 0.05 ug m l . Both-1 non-volatile metabolites and volatile metabolites of Trichoderma strains showed strong inhibition against B. cinerea isolates under experimental conditions. The highest growth inhibition percentage was determined with volatile metabolites of Trihoderma atroviride EGE-K-71 strain as 71.8%. Interpretation: secondary metabolites and volatile compounds of Trichoderma strains produced in both liquid culture and dual culture conditions The study suggest that filtrates that contain can be used as an effective fungal control agents against pre and postharvest contamination of grapes with Botrytis cinerea.