In vitro evaluation of the suitability potential probiotic of lactobacilli isolates from the gastrointestinal tract of chicken

Probiotic lactobacilli could be used to decrease the colonization of pathogenic bacteria in chicken and therefore decrease the risk of foodborne illness to consumers. The present study was conducted to select appropriate microbial strains for the development of potential probiotic. In experiment 1, 18 strains of lactobacilli isolated from the gastrointestinal tract of chicken were evaluated. The strains were demonstrated for their lactic acid, hydrogen peroxide, and exopolysaccharide productions. For experiment 2, the strains were tested for their acid, bile, antimicrobial activity, and antibiotic resistance levels. Among them, Lactobacillus delbrueckii ssp. delbrueckii BAZ32, Lactobacillus acidophilus BAZ29, BAZ36, BAZ43, and BAZ63 which produced high EPS were selected to aggregation ability. It is concluded that L. delbrueckii ssp. delbrueckii BAZ32, L. acidophilus BAZ29 confer high tolerance to acid, bile, antibiotic resistance, high antimicrobial activity, aggregation ability, and EPS production. These strains may be functional feed additives as potential probiotic in chicken.     

pH‐sensitive dimethylaminoethyl methacrylate (DMAEMA)/acrylamide (AAm) hydrogels: Synthesis and adsorption from uranyl acetate solutions

A random copolymer of dimethylaminoethyl methacrylate (DMAEMA) and acrylamide(AAm) [poly(DMAEMA/AAm)], with a pH‐sensitive character, was prepared by a redox polymerization method. Increasing the DMAEMA content of the gel, the pH, and the ionic strength of the solution decreased the swelling ratios of the hydrogels. The adsorption of poly(DMAEMA/AAm) hydrogels from uranyl acetate (UA) solutions was studied at different pHs. The adsorption capacity of hydrogels increased from 200 to 1200 mg of UA per gram of dry hydrogel with increasing pH of the adsorption solution. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2028–2031, 2003     

Metabolic activities of Lactobacillus spp. strains isolated from kefir

A total of 21 strains of Lactobacillus species were isolated from Turkish kefir samples, in order to select the most suitable strains according to their metabolic activities including probiotic properties. As a result of the identification tests, 21 Lactobacillus isolates were identified as L. acidophilus (4%), L. helveticus (9%), L. brevis (9%), L. bulgaricus (14%), L. plantarum (14%), L. casei (19%) and L. lactis (28%). The amount of produced lactic acid, hydrogen peroxide, proteolytic activity, and acetaldehyde productions of Lactobacillus spp. were determined. Different amounts of lactic acid were produced by strains studies; however, lactic acid levels were 1.7-11.4 mg/mL. All strains produced hydrogen peroxide. L. bulgaricus Z14L strain showed no proteolytic activity, L. casei Z6L strain produced the maximum amount (0.16 mg/mL) of proteolytic activity. Acetaldehyde concentration produced in Lactobacillus strains ranged between 0.88-3.52 microg/mL.     

Mobile Robot Motion Framework Based on Enhanced Robust Panel Method

International Journal of Control, Automation and Systems - This paper proposes a framework for the mobile robot motion in partially unknown static and dynamic environments. Its main part is a path...     

Swelling behavior and determination of diffusion characteristics of acrylamide–acrylic acid hydrogels

In this study, a random copolymer of acylamide and acrylic acid [poly(AAm‐co‐AA)] was prepared by a redox copolymerization method of their aqueous solutions. The effects of initial AAm/AA mole ratio, PEG 4000 content, and N,N′‐methylenebisacrylamide concentration on swelling behavior were investigated in water. Average molecular weights between crosslinks, percentage swelling, swelling equilibrium values, and diffusion/swelling characteristics (i.e., the structure of network constant, the type of diffusion, the initial swelling rate, swelling rate constant) were evaluated for every hydrogel systems. The hydrogels showed mass swelling capabilities in the range 789–1040% (for AAm/AA hydrogels), 769–930% (for AAm/AA hydrogels in the presence of PEG 4000), and 716–1040% (for AAm/AA hydrogels containing different concentrations of the crosslinker). The swelling capabilities of the hydrogels decreased with the increasing AA, PEG 4000, and crosslinker concentrations. The diffusion of water into AAm/AA hydrogels was found to be a non‐Fickian type. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1289–1293, 2004     

Phenylalanine ammonia lyase (PAL) enzyme activity and antioxidant properties of some cyanobacteria isolates

In the present study, six cyanobacteria isolates were evaluated for the PAL enzyme activity, and their methanol extracts were assessed for the total phenolic amount and other antioxidant parameters. Synechocystis sp. BASO444 and Synechocystis sp. BASO673 isolates with high levels of total phenols (66.0 ± 1.2 μg/mg, 78.1 ± 1.8 μg/mg, respectively) also showed high levels of PAL activities (20.5 ± 3.1 U/mg protein, 17.2 ± 2.3 U/mg protein, respectively) and strong antioxidant activities. To understand the effect of l-phenylalanine (l-phe) on the PAL activity, total phenolic amount, and phenolic constituents, isolates were evaluated with 100 mg/l l-phe. While PAL activities exhibited no significant change with l-phe addition, total phenolic amount of the isolates significantly increased. HPLC analysis revealed gallic acid, trans-cinnamic acid, p-coumaric acid, and ferulic acid as the main compounds. Results suggested that the two isolate mights be an important source for the l-phe inducible phenolic compounds.     

A modelling study on hydrolysis of whey lactose and stability of β-galactosidase

In the present study, the effect of process conditions on whey lactose hydrolysis and enzyme inactivation were investigated. The experiments were carried out in 250 mL of 25 mM phosphate buffer solution by using β-galactosidase produced from Kluyveromyces marxianus lactis in a batch reactor system. The degree of lactose hydrolysis (%) and residual enzyme activity (%) against time were investigated versus lactose concentration, enzyme concentration, temperature and pH. The mathematical models were derived from the experimental data to show the effect of process conditions on lactose hydrolysis and residual enzyme activity (in the presence and absence of lactose). At the optimum process conditions obtained (50 g/L of lactose concentration, 1 mL/L of enzyme concentration, 37 °C of temperature and pH 6.5), 81% of lactose was hydrolyzed and enzyme lost its activity by 32%. The activation energy for hydrolysis reaction (E _A ) and the enzymatic inactivation energy (E _D ) were calculated as 52.7 kJ/mol and 96.7 kJ/mol. Mathematical models at various process conditions have been confirmed with the experimental results.     

DESULFURIZATION 0F TURKISH LIGNITES BY CHLORINOLYSIS

ABSTRACT

The reduction and removal of sulfur compounds from Çan K4 (Çanakkale), Keles (Bursa) and Agaçli (Istanbul) lignite samples, obtained from mines close to Istanbul, was studied using chlorine gas Water or mixtures of methyl chloroform-water and carbon tetrachloride-water were used as solvents. Chlorine gas was bubbled through a suspension of lignite sample in solvent for about 1 to 5 hrs. It was observed that removal of sulfur increased with increasing time. Chlorinolysis and the Meyers method were used separately to compare their effects on the reduction of sulfur from Agaçli end Keles lignite samples. Chlorinolysis was found to be more effective than the Meyers method In the removal of organic sulfur and thus the total sulfur.