The aim of this study is to evaluate the biodegradable packaging materials which will be an alternative to traditional synthetic packaging materials. For this purpose, packaging films containing polycaprolactone (PCL), montmorillonite (MMT), and organically modified montmorillonite (OMMT) were prepared by solution casting method, and the mechanical, physical, structural, antimicrobial, and antifungal properties of these films were examined. Cetyl trimethyl ammonium bromide (CTAB) was used for the modification of montmorillonite. The structural properties of the prepared films were characterized by attenuated total reflection-Fourier transform infrared, X-ray powder diffraction, thermogravimetric analysis, and scanning electron microscopy. The PCL/OMMT structure was found to be thermally more stable than the PCL/MMT structure. The addition of OMMT to PCL improved the thermal and mechanical properties of the films compared with the pure PCL and PCL/MMT films. In addition, adding MMT/OMMT to the PCL caused an increase in the hardness of the films. In the antimicrobial analysis, while no inhibition effect was observed in PCL/MMT films, PCL/OMMT films showed inhibition effect against Staphylococcus aureus. Antifungal tests performed with the prepared films showed that the film-wrapped bread did not deteriorate for 40 days. It is thought that PCL/MMT and PCL/OMMT films prepared in this study will provide an advantage in applications as packaging material.
The lignocellulosic hydrolysates provide a rich medium for fermentation of sugars into ethanol. The potential use of sunflower seed hull hemicellulose hydrolysate in ethanol fermentation was evaluated by using the Experimental Design method in this study. A 2 2 Box-Wilson experimental design was used to develop a statistical model. The effects of shaking rate (55-145 rpm) and initial pH (4.6-7.4) on the fermentation of hydrolysate with Pichia stipitis yeast were studied in shaking bath experiments at 30C. Model equations that represent maximum ethanol concentration E max and ethanol yield Y P=S in terms of shaking rate and pH were developed by using the Design-Expert package program. From response surfaces, optimum variables were calculated numerically by the Design-Expert computer program. Such a procedure provided the optimum values of the parameters with respect to both Y P=S and E max as X 1 ¼ 5.89 pH and X 2 ¼ 114.6 rpm. The maximum ethanol concentration of 11.04 g=L and ethanol yield of 0.32 were obtained with these optimized parameters.
The axial and radial effective thermal conductivities of a monolithic ceramic catalyst support and of porous alumina pellets were measured using the moment technique. At 180 °C, radial and axial thermal diffusivities were determined as 9.3 x 10-3 and 11.1 x 10~3 cm2is-1, respectively. Having pores being filled with hydrogen, the corresponding thermal conductivity values are 0.43 and 0.52 Wm_1'K_1, respectively. Experimental results obtained between 110 and 180 °C indicated a negligibly small dependence of effective thermal conductivities on temperature. A proposed model which included the geometrical parameters of the monolith and the thermal conductivity ratio of the ceramic catalyst support to gas was shown to give excellent agreement with experimental results. Thermal conductivities of alumina pellets having bidisperse pore structures were also measured using this dynamic procedure. Experimental effective thermal conductivity values ranged between 0.043 and 0.120 W-m^K"1 for pellets having porosities between 0.79 and 0.57, respectively.
The use of clinoptilolites of Western Anatolia in detergents as phosphate substitutes was investigated. The cations present in the clinoptilolite samples were first exchanged with sodium ions. The washing characteristics of detergent mixtures containing surfactants, clinoptilolite, sodium carbonate and sodium sulphate were analysed. The stains of coffee, tea and tomato paste were tested. The washing tests were repeated for different surfactants, i.e. linear alkyl benzene sulphonate, sodium alkyl sulphate and alcohol ethoxylate and for different co-builders, i.e. sodium carbonate and EDTA. In addition, the effects of detergent dose and detergent formulation on washing were investigated. Other factors affecting the degree of soil removal such as shaking time, temperature and water hardness were also studied. The contribution of clinoptilolite to the washability was compared with zeolite A, zeolite X and sodium tripolyphosphate.Increasing the shaking time and temperature improves the degree of cleaning. LAS was the most effective surfactant for use with clinoptilolite. The washing performance of the detergent mixtures used in the present work was found to be comparable with that of commercial detergents at low washing temperatures.
Bioaccumulation of dye with C. tropicalis Growth and Inhibition Kinetics of C. tropicalis Effect of pH and sugar concentration on growth and dye bioaccumulation of C. tropicalis Figure A. The removal of metal-complex dye with Candida tropicalis Purpose: In the present study, we investigated the bioaccumulation of C.I. Acid Violet 90 1:2 metal complex dye (AV90) with Candida tropicalis in a batch system. Molasses was chosen as a source of carbon for the yeast The effects of pH, the dye concentration and the total sugar concentration on dye bioaccumulation and yeast growth were analyzed. In order to describe the inhibitory effect of AV90 dye on growth and bioaccumulation properties, the linear mixed-type inhibition kinetic model was used. Theory and Methods: During dying process, nearly 10-15% of the dyes and other chemicals are released into the environment. Physical, chemical, and biological treatment processes are involved in dye wastewater treatment. For bioremediation of dyes, several studies have focused on a wide variety of microorganisms which are capable of decolorizing a wide range of dyes. Yeasts, which is a low-cost and convenient source of microorganisms, have long been known to be capable of bioaccumulation of dyes under a wide range of external conditions. Dye bioaccumulation experiments with C. tropicalis were carried out in a 250 mL volumetric flask at a working volume of 150 mL at 30 °C in a shaking bath for 15 days (140 rpm) with dye adapted yeast. Results: The effect of pH on bioaccumulation was investigated at different initial pH values (3-6). The maximum specific growth rate of C. tropicalis and bioaccumulation percent of dye were obtained as 0.22 1/h and 50.3% at pH 5. Dye bioaccumulation and specific growth rates were found to be strongly depend on both initial total sugar and AV90 concentration. Monod equation was used to determine the relationship between growth and substrate (reducing sugar concentration) in the bioaccumulation of AV90 with C. tropicalis. It is observed that the inhibition of AV90 dye is a mixed type inhibition which is defined as a mixture of partial competitive and non-competitive inhibition. The Monod saturation constant (KS, g/L) and maximum specific growth rate (m, 1/h) of control medium without dye were obtained as 1.21 g/L and 0.267 1/h for C. tropicalis. The maximum growth rate mI decreased from 0.267 to 0.227 1/h while the K I S Monod saturation constant values increased from 1.21 to 1.68 g/L (K I S) for the increasing AV90 concentration from 0 to 400 mg/L. The inhibition constant, KI was obtained as 1008 mg/L from lineer mixed type equation. Conclusion: In this study, the removal of metal-complex azo dye (AV90) from aqueous solutions was investigated by using C. tropicalis. In the process of AV90 removal, the effect of pH, initial dye concentration and reducing sugar concentration on yeast growth and dye bioaccumulation were investigated, and it was observed that these parameters affect both yeast growth and the bioaccumulation of dyes. As a result, the e...
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