[Evaluation of Malassezia furfur Biofilm Formation on Polypropylene Membrane]. / Polipropilen Membran Üzerinde Malassezia furfur Biyofilm Olusumunun Degerlendirilmesi.

The Malassezia yeast species colonize on the skin immediately after birth and could be found on the healthy skin flora for life. Although they are more frequently involved in the etiology of common skin infections in the community, particularly Malassezia furfur could cause life-threatening infections such as fungemia. Detection of biofilm during the colonization of these yeasts on the skin is an important criterion for its virulence. Since they are lipophilic yeasts, commonly used biofilm detection methods are not applicable to the Malassezia strains. The aim of the study was to describe the growth and measurement of M.furfur isolates on a polypropylene membrane to demonstrate their biofilm-forming capacities. Twenty-seven M.furfur strains colonized in the newborns were included in the study. Basically, sterile polypropylene membranes were placed on different polysorbates (tween 20, 40, and 80) which were spread on Sabouraud dextrose agar. Ten µl saline suspension of M.furfur was dropped on the polypropylene membrane and incubated in standard growth conditions for three days. Later, the visible colony was removed gently by washing with running water and the biofilm structure formed on the membrane was stained with safranin. The stained biofilm was photographed. Performing image analysis, the values obtained against background activity were digitized according to the specified protocol. Moreover, XTT reduction test was performed and the measured metabolic activity results were compared with the safranin-stained biofilm data. The safranin hydrolysis of the strains was measured spectrometrically. Twenty-five (92.6%) of the strains included in the study were stained with safranin, which indicated the presence of biofilm on the polypropylene membrane. The strains grown with tween 20 and tween 80 formed a higher biofilm layer density than those supplied with tween 40. Isolates with low and high biofilm-forming capacity were clearly separated by tween 20 (p< 0.05). XTT activity was detected in 26 (96.3%) isolates. No correlation was found between biofilm density obtained by the described method and XTT reduction. It was observed that hydrolysis of safranin did not affect the biofilm evaluation method. In this study, it was shown that as a result of sufficient diffusion through hydrophobic membranes, polysorbate-based growth factors could maintain measurement of the biofilm layer formed by lipophilic M.furfur strains. The best grouping properties for M.furfur were obtained with tween 20 which could determine low and high level of biofilm formation. Image analysis was used with high performance for this method. As conclusion, the utilization of different hydrophobic membranes and dyes would lead to the development of new techniques for the application in other lipophilic yeasts.

Separation of Boron from Geothermal Waters with Membrane System.

This study presents the separation and recovery of boron from geothermal waters with a polymeric membrane system and suggests a transport mechanism. The optimum relative parameters of the transport were examined. The recovery value of boron was 60.46% by using polymeric membrane system from prepared aquatic solution to the acceptor phase. The membrane's capacity and selectivity of the transport process were examined. Kinetics values were calculated for each transport parameter. The optimum kinetic values were 1.4785 × 10-6 (s-1), 7.3273 × 10-8 (m/s), 13.5691 × 10-8 (mol/m2.s), 5.8174 × 10-12 (m2/s) for constant rate, permeability coefficient, flux, and diffusion coefficient, respectively. Boron was transported selectively and successfully from geothermal waters in the presence of other metal cations with 59.85% recovery value. This study indicates the application of real samples in polymeric membrane systems, which are very practical, economic, and easy to use for large-scale applications. The chemical and physical properties of polymer inclusion membranes (PIMs) offer the opportunity to be specially designed for specific applications.

New Type Biomembrane: Transport and Biodegradation of Reactive Textile Dye.

In traditional separation processes, there are environmental risks still because of the presence of toxic agents. Thus, a novel biomembrane microreactor named eco-green biomembrane (EgBM) was developed to perform the transport, biodegradation, and cleaning of a textile dye aqueous solution (3 mg/L) from the donor (i.e., textile dye) to the acceptor (i.e., laccase enzymes) phases. In the present work, Morchella esculenta pellets were used as carriers and degraders instead of using the traditional chemical carriers. The optimized EgBM was made of cellulose triacetate (16.1%) as a base polymer, 2-nitrophenyl octyl ether (25.2%) as a plasticizer, and M. esculenta fungus pellets (58.7%) as both carriers and degraders. A decoloration percentage of 98.6% ± 0.8 in 60 h was attained, which was due to two mechanisms: biosorption (15.4% ± 0.1) on fungal mycelium and biodegradation (83.2% ± 0.6) by laccase enzymes. The EgBM was achieved not only by the transport of reactive textile dyes used in the donor phase but also by the biodegradation and biosorption of the dyes.

A novel electro-driven membrane for removal of chromium ions using polymer inclusion membrane under constant D.C. electric current.

In this study, the use of polymer inclusion membrane under constant electric current for the removal of Cr(VI) from water has investigated for the first time. Transport of Cr(VI) is performed by an electric current from the donor phase to the acceptor phase with a constant electric current of 0.5A. The optimized membrane includes of 12.1% 2-nitrophenyl octyl ether (2-NPOE), 77.6% cellulose triacetate (CTA), 10.3% tricapryl-methylammonium chloride (Aliquat 336) as a carrier. We tested the applicability of the selected membrane for Cr(VI) removal in real environmental water samples and evaluated its reusability. Electro membrane experiments were carried out under various parameters, such as the effect of electro membrane voltage at constant DC electric current; electro membrane current at constant voltage, acceptor phase pH, and stable electro membrane; and a comparison of polymer inclusion membrane and electro membrane transport studies. The Cr(VI) transport was achieved 98.33% after 40min under optimized conditions. An alternative method has been employed that eliminates the changing of electrical current by the application of constant electric current for higher reproducibility of electro membrane extraction experiments by combining the excellent selective and long-term use features of polymer inclusion membrane.