Macmillanthorup6716

Ballast water is one of the most important ways for the transfer of aquatic organisms such as

(

) and

. The aim of this study was to investigate

gene of

and the

gene of

bacteria by PCR technique in the ballast water of commercial ships entering Bushehr port along the Persian Gulf.

In this study, 34 samples of ballast water entered Bushehr port were studied by using culture and PCR methods to determine

gene of

and

gene of

. Genomic DNA of bacterial strains was extracted and PCR was performed by using specific primers of

and

.

The specific

gene of

was detected in 4 ballast water samples and the positive samples were analyzed by antisera methods for E. coli O157H7. Results of antisera showed that there were 3 positive samples of O157H7 serotype. The results of the PCR technique showed that the

gene of

was negative for all positive culture samples.

Further studies are highly recommended to monitor other aquatic organisms in ballast water to protect the marine environment.

Further studies are highly recommended to monitor other aquatic organisms in ballast water to protect the marine environment.A biosurfactant producing strain was isolated and the rhamnolipid type biosurfactant was extracted for soil washing of a synthetically and naturally hydrocarbon-contaminated soil. Following the primary screening, Pseudomonas aeruginosa strain R 4 was selected and the effect of the carbon and nitrogen source and the salinity on biosurfactant production was studied. Of the best results were observed for glucose as a carbon source, NH4Cl as a nitrogen source and salinity of 1.4%. The produced biosurfactant was a glycolipid type biosurfactant and reduced the surface tension to 32.5 mN/m with a critical micelle concentration (CMC) of 50 mg/L and production yield of 90 mg/L. Using produced biosurfactant, a pyrene desorption rate of 82% was observed in selected conditions for initial pyrene concentration of 200 mg/L.Algae are known with many detrimental impacts on drinking water quality. Discharge of municipal and agricultural wastewater into the receiving water resources make desirable conditions for algae growth and consequently cause eutrophication phenomena. Water samples were withdrawn monthly from 5 stations in Zabol City within spring and summer seasons. To identify algae species, micronutrients, and physical parameters such as temperature, depth of Secchi disk (SD) and pH on their growth were evaluated. The average phosphate in spring and summer were observed to be 0.034 and 0.028 mg/L, respectively. The results obtained from the present study indicated that the volume and depth of the water reservoirs were less critical on total phosphorus compared with the concentration of algal cells and total nitrogen. The mean pH for water samples taken from Chah Niemeh (CN) in spring and summer were observed to be 8.4 which is suitable for algae growth. Furthermore, the mean temperature (>20 °C) in both seasons were found to be desirable for the growth of algae, especially cyanobacteria in the CN. Moreover, the mean SD in spring and summer samples was 96.16 m and 119.83 m, respectively. As a result, the reservoir had low transparency in terms of algal growth. Totally, most of the identified algae were green algae (50%), algal flagella (19%), cyanobacteria (15.4%) and diatoms (15%). Therefore, cyanobacteria are most possible responsible for the taste and odor in the CN water reservoir. Future efforts should be directed toward preventive measurements for protecting water reservoirs from municipal and agricultural wastewaters and algae control.

Honey is a promising source of bacterial strains producing metabolites with antimicrobial activity. There is a great variety in the antimicrobial activity of honey from different areas of nature. Therefore, the aim of present study was to investigate the antibacterial activity of Iranian honey from different regions and to optimize the culture condition for the highly potent bacterial isolate.

Honey samples were collected from ten different regions of Iran and were screened for bacteriocin-producing bacteria. The best bacteriocin-producing strain was characterized and identified by 16S rDNA analysis. One-factor-at-a-time method was used for optimization of culture medium and the yield and time-course of bacteriocin production were compared in both shake flask and bio-reactor.

The

SB1 that was isolated from Sabalan honey showed potent antibacterial activity with prominent thermal stability. The optimum medium for the bacteiocin production was a yeast extract-based medium. The optimum incubation temperature for bacteriocin production was 34°C. Bacteriocin production was higher near neutral pH conditions than that produced at acidic or alkaline environment. The results of cell growth and bacteriocin assays revealed that the exponential phase of growth and antibacterial compounds production was started rapidly in bioreactor than flask.

Findings of this study supported the folkloric application of honey against some infectious diseases.

SB1 that isolated from Sabalan honey was a potential source for bacteriocins-like compounds. Our studies suggested a simple buffered nitrogen-based medium for SB1 growth and bacteriocin activity in both shake flask and bioreactor.

Findings of this study supported the folkloric application of honey against some infectious diseases. (R)-2-Hydroxyglutarate B.subtilis SB1 that isolated from Sabalan honey was a potential source for bacteriocins-like compounds. Our studies suggested a simple buffered nitrogen-based medium for SB1 growth and bacteriocin activity in both shake flask and bioreactor.

The purpose of this study was to develop antimicrobial bioplastics based on Poly Lactic Acid (PLA) with the addition of chitosan-ZnO, and chitosan-TiO

to improve antimicrobial properties.

For the preparation of the bioplastics, PLA with chitosan-ZnO or chitosan-TiO

were used. The antimicrobial activity, mechanical and thermal properties, and water vapor permeability of bioplastics were evaluated.

PLA-chitosan-ZnO indicated a robust antimicrobial activity against bacteria such as

,

,

,

, yeast such as

, and fungus

. No formation of new functional groups in PLA-chitosan-ZnO composites. In comparison to other PLA-based bioplastics, this bioplastic has medium tensile strength, tensile modulus, and elongation percentages with low barrier ability to water vapor. Chitosan-ZnO itself has a greater tensile strength compared to chitosan-TiO

. These two compounds undergo 2 stages of decomposition in a temperature range of 43°C to 265°C. The addition of PLA into chitosan-ZnO or chitosan TiO

causes the bioplastics decomposed in a single stage.