Screening for and characterization of Lactococcus lactis bacteriophages with high thermal resistance

Fifty-six Lactococcus lactis phage isolates collected from different German dairies and obtained from a starter culture manufacturer were tested for their heat resistance. About 40% of these isolates resisted treatment at 80 °C for 5 min when they were heated in milk. The most resistant phage isolate, P1532, was collected from sour cream. Plaque-formation was still detectable even after heating at 97 °C for 5 min. The second heat-resistant one, P680, showed some plaque-forming ability after heating at 95 °C for 5 min. Kinetic parameters for the thermal inactivation of these two resistant phages were determined for temperatures ranging from 70 to 97 °C. The inactivation of phage P1532 in skim milk and in buffer medium were found to follow first-order kinetics and did not exhibit tailing, whereas in the inactivation curves of phage P680 tailing was observed. The D-value of P1532 at pasteurization temperature of 72 °C was calculated as 112 min.     

Reuse of glass waste in the manufacture of ceramic tableware glazes

Today, various studies are carried out to spread the understanding of sustainability. The sustainability of production processes gains importance in corporate areas. In this study, the use of glass waste instead of frit used in glaze compositions in the ceramic industry was evaluated. The chemical and physical properties of glass wastes on samples were examined. The glaze formulations were prepared using 3%, 5%, and 8% by weight of glass waste instead of frit. Glass wastes were added to glaze compositions and 12 different glaze formulation studies were carried out. Transparent, Opaque, and Matte test glazes were prepared with glass waste added glaze formulations, and these glazes were applied to ceramic bodies. SEM (scanning electron microscope) analysis of standard glaze and glass waste added glazes was performed to determine the microstructural and morphological characterizations. Also, surface whiteness, brightness, L*a*b values, glaze flows, harcort test results, and final water absorption values were compared. As a result of the studies, it has been determined that it is appropriate to use 3% glass waste by weight instead of the frit in the production of ceramic tableware.     

Evaluating the role of uniformity on the properties of B4C–SiC composites

Fully dense boron carbide-silicon carbide composites were successfully produced by spark plasma sintering method at 1950 °C under 50 MPa applied pressure. The effect of dry and wet mixing methods on uniformity was observed. Density, elastic modulus, microstructure, Vickers hardness and fracture toughness were evaluated. The results showed that dry mixing did not provide uniformity on composites properties. On the other hand wet mixing provided uniformity in microstructure and consistency in material properties. The hardness of the sample containing 50 wt% B₄C was measured to be 30.34 GPa hardness value was found at 50 wt% B₄C content sample. The increase in the B₄C content of the composites decreased the Young's modulus, shear modulus, bulk modulus and fracture toughness. The highest values were found at 10 wt% B₄C sample which were 415 GPa (E), 177 GPa (G), 209 GPa (K), and 2.89 MPa m^1/2 fracture toughness (K_Ic).     

Solid‐phase extraction of lead and copper on a polyhydroxybutyrate‐b‐polydimethyl siloxane (PHB‐b‐PDMS) block copolymer disc and flame atomic absorption spectrometric determination of them in water and food samples

A separation and preconcentration procedure based on solid‐phase extraction of Cu(II) and Pb(II) as their Sudan III chelates on polyhydroxybutyrate‐b‐polydimethyl siloxane (PHB‐b‐PDMS) block copolymer disc has been established. Various analytical parameters including pH, amount of Sudan III, eluent type and volume, sample volume, flow rates were optimised. The effects of concomitant ions on the retentions of the analyte ions on PHB‐b‐PDMS disc were also examined. The detection limits for Cu(II) and Pb(II) were found to be 2.3 and 4.9 μgL^?1, respectively. Preconcentration factor was found to be sixty. Relative standard deviation was found to be 5%. The accuracy of the method was confirmed by analysing certified reference materials (TMDA 54.4 fortified lake water and NIST 1515 Apple leaves). Optimised method was applied to determine the analyte ions in various water and food samples from Turkey.     

Fenton and Fenton‐like oxidation of CI Basic Yellow 51: a comparative study

When ferric ions are substituted for ferrous ions in Fenton’s reagent, the reactions which occur are called Fenton‐like reactions. This study describes the relative efficiency of Fenton (with ferrous ions) and Fenton‐like (with ferric ions) reactions for the degradation of a basic dyestuff, CI Basic Yellow 51, in aqueous solution. Comparisons were made on the basis of the observed reductions in chemical oxygen demand and visible absorption of the dye solutions at optimum reaction conditions. It was found that the Fenton process with 2.63 mm ferrous ion and 39.96 mm hydrogen peroxide at the optimum pH (3.0) eliminated 92.2% of chemical oxygen demand and 98.9% of colour in 22 min, whereas 43.2% of chemical oxygen demand and 64.6% of colour was eliminated by the Fenton‐like process within the same time period, but at pH 4. The efficiency of the latter was significantly improved (to 96.6% removal of colour and 99.7% removal of chemical oxygen demand) by an increase in temperature of 35 °C (from 15 to 50 °C), while no improvements were observed in the efficiency of the Fenton process by temperature elevations.     

Synthesis and Characterization of Novel Surfactants: Combination Products of Fatty Acids,Hydroxycarboxylic Acids and Alcohols

The reaction of hydroxycarboxylic acids, such as citric, malic and tartaric species with an excess of fatty acid chlorides produces the corresponding O-acylated hydroxycarboxylic anhydrides in one step and in a near quantitative yield. These molecules are excellent electrophiles which react readily with a variety of nucleophiles including alcohols, diols and polyols. Their reaction with triethylene glycol and triethylene glycol monomethyl ether leads to two series of novel anionic surfactants, which are unsymmetrical gemini surfactants. The determination of their properties (CMC, foaming, HLB) revealed that these molecules are—depending on the chain length of the fatty acid—excellent emulsifiers, and that they also display interesting antimicrobial activity. These novel functional surfactants are of interest for applications in food and personal care products and for the formulation of pharmaceuticals.