In this research work, TiO2, TiO2-Graphene, and TiO2-Graphene/ALGINATE catalysts were synthesized and characterized by different methods such as XRD, TEM, SEM, and EDX analysis methods. Photocatalytic activity of prepared samples was investigated by photocatalytic removal of malachite green and methyl orange as cationic and anionic dyes from aqouse solutions. The results showed that photocatalytic activity of samples depends on the chemical structure of pollutants. TiO2-Graphene/ALGINATE nanocomposite showed higher photocatalytic activity on the removal of cationic dye from aqouse solutions. While TiO2-Graphene sample showed higher photocatalytic activity on the removal of anionic dye from aqouse solutions comparison. The figures of merit based on electric energy consumption (electrical energy per order (EEO)) were evaluated in the photodegradation of malachite green in the presence of prepared samples. The results indicate that less energy is consumed during the degradation of malachite green in the presence of TiO2-Graphene/ALGINATE compared with other photocatalysts. To understand the nature of adsorption process, the equilibrium adsorption isotherms were studied. Based on results, for TiO2-Graphene/ALGINATE, Langmuir isotherm model with correlation coefficient of 0. 995 fitted the experimental data, respectively. According to the Langmuir isotherm model, the maximum adsorption capacity of TiO2-Graphene/ALGINATE for adsorption malachite green was about 86. 45 mg. g^(-1), which was about 4 times the adsorption capacity of Ag-TiO2. Also, recyclability of TiO2-Graphene/ALGINATE nanocomposite was investigated. The results showed that TiO2-Graphene/ALGINATE nanocomposite with recycling ability is highly stable.

Background: This study was designed to compare antimicrobial activity of ALGINATE and ALGINATE-resistant starch micro particles against Listeria monocytogenes.Methods: Nisin loaded micro particles were prepared by a w/o-emulsion external cross-linking procedure with three weight ratio of nisin to ALGINATE (4: 1, 2: 1 and 1: 1). For comparison of the antimicrobial activity of nisin encapsulated in ALGINATE and ALGINATE-resistant starch micro particles, the release of nisin from micro particles was studied in distilled water as release medium and activity of released nisin was determined using the food pathogen Listeria monocytogenes ATCC 19117in agar diffusion test. Three wells of 6 mm diameter were punched into the agar on each plate (that seeded by 100ml of an overnight broth culture containing 107-108 CFU/ml of the test organisms) and lyophilized microcapsules were loaded into wells. Plates were incubated at 37oC for 24 h. The diameter of inhibition zone was then measured. The amount of released nisin from micro particles was determined using bacteriocin standard curve.Results: The nisin release from all formulations occurs in two stages: first, a rapid release phase, which corresponds to nisin being physically entrapped in the surface of micro particles, and second, the nisin being gradually released, until the nisin content was constant (66-76% in Alg microparticles and 61-70% in Alg-RS micro particles). The releasing of nisin depended on the initial bacteriocin content. When the nisin content increased, the amount of released nisin was found to decrease In addition, lower rate releases were found in ALGINATE- resistant starch micro particles. This lower rate release for ALGINATE-resistant micro particles in comparison to ALGINATE micro particles was attributed to the presence of resistant starch in ALGINATE matrix that retarded the release of nisin.Conclusion: Cumulative release of nisin from ALGINATE-resistant starch micro particles occur in a controlled manner and antimicrobial activity of nisin in this micro particle is maintained for a longer period of time which this long lasting antimicrobial activity useful in food matrixes.

ALGINATE belongs to a group of natural polymers called polysaccharides. They have carboxylic functional groups beside hydroxyls which are common in all polysaccharides. These materials show interesting properties due to their functional groups. One of these properties is the ability of this polymer as a suitable carrier of protecting and transferring drugs and biomolecules. The particle sizes of these polymers are very important for their applications, so different techniques were used for preparation of these materials. In this way polymeric nanoparticles of calcium ALGINATE which are excellent carriers in drug delivery systems were prepared by addition of calcium chloride solution to dilute solution of sodium ALGINATE. Investigation of the size and distribution of nanoparticles were analyzed by SEM method. The concentration effects of both ALGINATE and calcium ions on the size and distribution of nanoparticles were studied in this research. Results showed that the size of nanoparticles obviously decreased with decreasing polymeric ALGINATE concentration because of lower active sites in polymer chain. On the other hand, the size and distribution of nanoparticles are significantly improved with increase of calcium cation concentrations. The mean particle size 40-70 nm and spherical shape are the main characteristics of the prepared nanoparticles.