Copper bioremoval by novel bacterial isolates and their identification by 16S rRNA gene sequence analysis

Copper-tolerant bacteria were isolated from soil samples taken from a region where metal industries are located. After selecting 2 isolates with relatively higher bioremoval efficiency, the effects of increasing copper concentration, pH, and temperature on the bioremoval efficiency of the growing isolates were determined. Strain N1c and strain N5a showed maximal bioremoval efficiency of 82% and 75%, respectively, in 20 mg/L copper-containing medium at pH 6.8 and 30 degrees C. Although the isolates did not grow well at pH 5, a low amount of copper was removed at pH 5. Slow growth of N5a at pH 5 allowed for 26% copper removal at hour 80 of incubation. Optimal copper bioremoval of the cells occurred at pH 6.8 and 30 degrees C. When grown at 37 degrees C under aerated conditions, N1c showed 31.7% bioremoval in the presence of 100 mg/L copper, and N5a was much more resistant to copper compared to NI c and E. coli. The isolates were identified by 16S rRNA gene sequence analysis. The 16S rRNA gene sequence of N5a showed 96%-97% similarity to Pseudomonas stutzeri and other Pseudomonas spp. The 16S rRNA gene sequence of N1c was 96% similar to Achromobacter sp., Alcaligenes sp., and a novel genus, Collimonas

Antioxidant activity of the fruits of Pyracantha coccinea using ethanolic extract method

Pyracantha coccinea Roem. (scarlet firethorn) is known as a medicinal plant that can be up to 3 m in height with lots of thorns, grown generally in South and Southeast Europe and Turkey. Pyracantha coccinea Roem is being used in folk medicine since its fruits have diuretic, cardiac and tonic properties. To determine the antioxidant level of the different parts of the plants takes interest in the current researches. In this study it has been aimed to evaluate the antioxidant and antimicrobial activity levels, Fe3+ reduction power and the total phenolic amount of the ethanolic extracts of the fruits of Pryacantha coccinea using DPPH scavenging, the disc diffusion, reduction power and Folin-Ciocalteu methods, respectively. IC50 value, which represents the 50% scavenging value of DPPH radical of prepared fruit extracts using the Maceration technique, is evaluated to be 36.53 µg/mL The total phenolic content is determined to be 199.6 mgGA/100g and Fe+3 ions are reduced to a certain amount for various concentration levels (from 20 to 100 µg/mL). From the current research we have also found that the fruits of Pyracantha coccinea have no any antimicrobial activity. As a general result of the current study it has been concluded that the fruits of Pyracantha coccinea have extremely higher level of antioxidant activity depending upon the phenolic contents, showing that they can be used in various food and health applications

Antibacterial and antioxidant activity of some seeds used as food

In this study, antioxidant and antibacterial activities of Brassica nigra, Linum usitatissimum, Salvia hispanica, Nigella sativa, Chenopodium quinoa seeds prepared with ethanol were determined. Antioxidant capacity has been measure by evaluating DPPH radical scavenging activity level and antibacterial activities were investigated by using the disc diffusion method. Highest antibacterial activity level has been detected for the seed of N. sativa. As a result of this study there exist no any antibacterial effect in the seeds of B. nigra and L. usitatissimum. The extract of N. sativa seed has shown an inhibition zone of 14.5 mm on Staphylococcus aureus, whereas this value has been detected to be 10.5 mm for both on the seeds of Enterococcus faecalis and Staphylococcus epidermidis. IC50 value showing the 50% scavenging value of DPPH radical has been determined to be 51 µg/mL for the seed extrafct of B. nigra as the highest one between the all seed samples searched. All seeds used in the current study which are known to be functional food have shown certain level of antioxidant activity

Alkaline protease production of Bacillus cohnii APT5

An obligate alkaliphilic Bacillus strain was isolated from a soil sample and identified as Bacillus cohnii APT5 based upon phylogenetic and phenotypic analyses. The optimum growth pH of B. cohnii APT5 was 10.0. B. cohnii APT5 was also found capable of producing an extracellular alkaline protease that showed optimum activity (693,318 U/min) at 50 degrees C and pH 11.0 when grown in a medium containing casein. The enzyme was partially purified 3.22-fold with a yield of 78.74% after acetone precipitation and cation exchange column chromatography, respectively. The partially purified enzyme maintained its activity when incubated at 50 degrees C for 2 h. It was stable at pH 11.0 at room temperature for 72 h. Furthermore, the alkaline protease activity was not completely inactivated by the specific inhibitors of serine alkaline proteases and metalloproteases such as PMSF and EDTA. While 1 mM PMSF had no effect on the enzyme activity, a 10 mM concentration of PMSF slightly decreased the activity, producing a relative activity of 76%. In addition, the enzyme was found to be very stable toward surface active agents such as SDS, Tween 20, Tween 80, and Triton X-100. None of the metal ions used (Ca2+, Mg2+, Zn2+, Fe2+, and Mn2+) showed an inhibitory effect on enzyme activity. On the contrary, APT5 alkaline protease activity increased 53% when treated with Mn+2. It was concluded that the active center of APT5 alkaline protease required Mn+2 as a cofactor. Based on the thermostability, pH stability, and resistance of B. cohnii APT5 alkaline protease against inhibitors, this enzyme may be very useful in commercial applications, particularly in the detergent industry

Investigation of antibacterial activity of juglone-poly(ε-caprolactone) - Alumina composite films

The aim of this study was to produce the Poly(ε-caprolactone)(PCL)-Alumina (Al2O3) composite films impregnated with Juglone and determine their antibacterial properties. PCLAl2O3 composite films containing 1% and 5% Juglone were prepared using the roll mill method. Juglone was chosen as the antibacterial agent in this study for the production of composite films due to its effective antimicrobial activity. The Juglone-Poly(ε-caprolactone)(PCL)-Alumina (Al2O3) composite films exhibited 100% antibacterial activity against both Staphylococcus aureus ATCC 29213 and Escherichia coli ATCC 25922. It was demonstrated that the JuglonePCL-Al2O3 composite films may have various potential applications in food packaging and personal care products in order to ensure the microbial safety and extended shelf life of the foods and the personal care products

Microbiology of public telephones

Conclusions: These results showed that public telephones are contaminated with various types of microorganisms and the level of contamination changes significantly with time. (C) 2005 The British Infection Society. Published by Elsevier Ltd. All rights reserved

Preparation of antimicrobial polycaprolactone-silica composite films with nanosilver rods and triclosan using roll-milling method

In this study, antimicrobial polycaprolactone composite films containing 12.5% silica and 0.15% silver nanorods were prepared using the roll-milling method. The destruction of E. coli and S. aureus on the surface of the composite films was evaluated after 6 hr of incubation at 37 degrees C. For the E. coli, no bacterial contamination was detected after 6 hr and the film surface was completely disinfected with 100% reduction of the microbial contamination. For the S. aureus, 94% reduction of the bacterial contamination was observed after 6 hr. The results were compared with the composite films containing triclosan, a broad-spectrum antimicrobial agent. The antimicrobial activity tests with 0.25% triclosan incorporated polycaprolactone-silica composite films showed only 70% reduction of E. coli and 95% reduction of S. aureus after 6 hr. The results demonstrated that the use of silver nanoparticles in the biopolymer industry has huge potential for the self-cleaning applications. Copyright (C) 2009 John Wiley & Sons, Ltd

EFFECT OF ACID CONCENTRATION ON THE EXTRACTION OF NICKEL FROM LATERITE

Nickel is essential metal due to usage area as stainless steel, non-ferrous alloy production, electroplating and chemical industry. Degradation of nickel sulphides leads to extraction of nickel from laterites. High cost equipment of high pressure acid leaching and since heap leaching needs longtime, atmospheric acid leaching of laterites becomes popular. Parameters of atmospheric leaching are important in terms of acid consumption, content of pregnant solution and residue. Therefore in this study, lateritic nickel ore from ManisaCaldag/Turkey was leached for determining acid concentration parameter, both sulfuric acid and nitric acid sulfuric acid mixture with varying percentage by volume. XRD analysis of lateritic nickel ore was showed that the ore mainly consist of quartz and goethite. Pregnant leach solutions were analyzed with atomic absorption and leach residues were characterized by X-ray diffraction and scanning electron microscopy. Increment of acid concentration caused increased nickel content in the solution but iron content increased as well

Effects of Sulfation Roasting and Sodium Sulfate Addition on Dissolution of Nickel and Cobalt from Laterite

In this study, lateritic nickel ore from Manisa-Caldag, Turkey was subjected to sulfation roasting. Experimental parameters were as follows, acid concentration (10-90 wt.%), roasting temperature (200-900 degrees C) and time (15-90 min). Effect of sodium sulfate addition (1-9 wt.%) on dissolutions of nickel and cobalt was also investigated. It was concluded that iron dissolution has increased with increased acid concentration. Dissolutions of nickel and cobalt increased with increasing roasting temperature and time below the decomposition temperature of related metal sulfates. It was concluded that addition of sodium sulfate in roasting stage has no significant effect on dissolutions of related metals