Potential of Azolla filiculoides in the removal of Ni and Cu from wastewaters

Heavy metals constitute a serious health risk because they accumulate in soils, water and organisms. One of the methods of removing these pollutants from water and soil is the use of plants. There are many plants (hyperaccumulators) which have the ability to accumulate large amounts of heavy metals. One of them is the aquatic fern Azolla filiculoides, which can bind some substances. A dried A. filiculoides biomass was used to remove heavy metal from aqueous solution using batch experiments. The aim of this study was to verify the ability of A. filiculoides to fix Ni and Cu from polluted waters. The maximum uptake capacities of the collected A. filiculoides from the Asbchin Wetland west of Mazandaran in the northern part of Iran at the optimal conditions for Ni and Cu ions were approximately 0.77 and 0.54 mmol/g (dry Azolla), respectively. Fourier transform infrared (FT-IR) spectroscopy was used to examine functional groups that may take part in the dried A. filiculoides biomass. Results showed that the amino, carboxyl and hydroxyl groups may be responsible for the biosorption of metal ions on the biomass. Desorption experiments indicated that  ethylenediaminetetraacetic acid (EDTA), HNO3 and HCl were efficient desorbents for recovery from Ni (II) and Cu (II).Key words: Azolla filiculoides, wastewater, batch biosorption, heavy metals

In vitro evaluation of antimicrobial activities from aqueous and methanolic extracts of cyanobacteria

In this present study, antimicrobial activities of aqueous and methanolic extracts of cyanobacteria against some of fungi and pathogenic bacteria were investigated. Cyanobacteria strains Fischerella ambigua ISC67 and Schizothrix vaginata ISC108 were cultured in BG-11 medium. Extraction was performed by adding the solvent to cyanobacterial biomass and then filtering and drying of the mixture. The antimicrobial activity was evaluated by disc diffusion method and broth microdilution method was applied to determine the minimum inhibitory concentration. The results show that the aqueous and methanolic extracts of F. ambigua has a significant antimicrobial effect while, the tested extracts of S. vaginata was no significant antibacterial and antifungal activity. Highest antibacterial activity from aqueous extract of F. ambigua was against S. aureus (PTCC 1112) which the average zone diameter around it was 33.33 mm. The antibacterial effect of aqueous extracts against Gram-positive bacteria was more than Gram-negative bacteria significantly. Antifungal activity showed that methanolic extract of F. ambigua have significant antifungal activity. Minimum inhibitory concentration of active extract against most tested bacterial and fungal was 125 mg/ml. The present study has proved that the aqueous and methanolic extracts of F. ambigua possessed strong antibacterial and antifungal properties against the pathogenic microorganism. Therefore, cyanobacteria can be a rich source for natural products with antimicrobial activity. DOI: http://dx.doi.org/10.5281/zenodo.346363

Biosorption of Cu (Ii) and Ni (Ii) ions from aqueous solution by marine brown algae Sargassum angustifolium

This study focused on the batch removal of Cu2+ and Ni2+ ions from an aqueous solution and wastewater using marine brown algae Sargassum angustifolium. With high capacities of metal biosorption and desorption, the biomass of S. angustifolium is promising as a cost-effective biosorbent for the removal of Cu2+ and Ni2+ from aqueous solution. According to X-ray photoelectron spectroscopic (XPS); the possible organic functional groups in the metal binding include carboxyl, amino, sulfhydryl and sulfonate groups. Langmuir, isotherm model were applied to describe the biosorption of the Cu2+ and Ni2+onto S. angustifolium biomass. The maximum uptake of Cu2+ and Ni2+ ions by the S. angustifolium biomass under the optimal conditions was approximately 0.94 and 0.78 mmol/g dry alga respectively. According to result biomass of S. angustifolium could be used as an effective biosorbent for the treatment of Cu2+ containing aqueous solution

Production and optimization of polyhydroxybutyrate (PHB) from Bacillus megaterium as biodegradable plastic

Among biodegradable plastics polyhydroxy alkanate and its polymers have received more attention than other biodegradable polymers because of their complete degradability, flexibility, water resistance and also the ease of production process. Polyhydroxybutyrate is one of the types of polyhydroxy alkanates that is seen as a storage granule in many microorganisms. In this study, Bacillus megaterium was prepared from Iranian microbial collection. Glucose and yeast extract were used as the main components of the medium in seed media 9 and 2.5 g/l and in fermentation medium 30 and 7.5 g/l respectively. GC-MASS and FTIR were used to identify the PHB produced. The results showed that the highest amount of biomass (0.221 g/l) and PHB (0.080 g/l) were obtained with glucose at 37°C and shaker speed of 150 rpm for 72 h incubation. The results of GC MASS and FTIR showed the production of PHB by Bacillus under investigation. Based on the mean of data on total cell growth conditions, the rate of cell biomass and PHB production in B. megaterium were 0.0869 and 0.0171 respectively. According to the results of the experiments, temperature had the greatest effect on biomass production and PHB production. The bioplastics produced by microbes are also highly degradable in the environment, and due to their specific chemical structure, they have been widely used in various fields of the food, pharmaceutical and chemical industries and are likely to replace today's plastics in the near future. DOI: http://dx.doi.org/10.5281/zenodo.371140

Biosorption of Ni (II) by bacillus sp. isolated from desert-maranjab soil

The objective of this research was to isolate microorganisms which produce uptake of nickel ions, from soils in Desert-Maranjab. In this study various soil samples were collected in Desert Maranjab and were cultured on nutrient agar and saboroud dextrose agar and the patent isolates were purified. Twenty soil samples were collected from various areas of Desert Maranjab, Iran .Initial screening of a total of 40 bacterial isolates at pH 5, resulted in the selection of one isolate with maximum uptake capacity of nickel ions 0.71 mmol.g-1 dry weights. A contact time of 10 min was sufficient to reach equilibrium. It was tentatively identified as Bacillus sp according to morphological and biochemical properties and named strain AEJ-89.This Bacillus sp gram positive bacteria were used to investigate the biosorption of Ni ions. In the next step the effects of some ecological parameters (temperature, pH, kinetics and isotherm were studied on the biosorption. The results obtained showed that the optimized conditions for the uptake nickel ions were as follow: Temperature 25ºC, pH= 7.8 - 7.2, and carbon sources (glucose and lactose 10 g / l). The equilibrium time was about 5 min and the adsorption equilibrium data were well described by the Langmuir`s equation

Evaluation of antioxidant and antibacterial activities of methanolic extract of medlar (Mespilus germanica L.) leaves

The present study evaluated the antioxidant and antibacterial activities of methanolic extract of medlar (Mespilus germanica L.) leaves. The antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl radical assay and the antibacterial activity was evaluated by the disc diffusion method and determination of minimum inhibitory concentration. The methanolic extract showed high antioxidant activity (69.43%) and had antibacterial activity against both Gram positive and Gram negative bacteria. Higher inhibition zone was detected against S. aureus (30.83 mm). The extract of this plant showed high phenolic, flavonoids and carotenoids contents and it can be concluded that these compounds may be responsible for antibacterial and antioxidant activity. The results indicated that the methanolic extract of medlar, M. germanica L., leaves possessed strong antibacterial and antioxidant properties and could be an important source of natural compounds for development of new drugs

Performance of dead Fucus serratus biomass in binary biosorption of Cd (II) and Ni (II) from aquatic habitat

Methods of physical and chemical adsorption of heavy metals have disadvantages in some ways- such as high cost and ineffectiveness at low concentrations. In recent decades methods of biological uptake of heavy metals have been investigated. The biological adsorbents include bacteria, fungi and alga, among which algae have the highest efficiency of metal uptake. This study indicated that Alginic acid is most responsible for the uptake of metals, such as nickel (II) and cadmium (II). Fucus serratus, brown alga, used as a cost-effective adsorbent for the biological uptake of cadmium and nickel ions simultaneously in a batch reactor in this study. Surface structure of algae has also been investigated. Adsorption kinetics have been measured and the results have indicated that the equilibrium time is about 300 minutes. The adsorption isotherm was interpreted by means of the Langmuir equation. The maximum adsorption rate for cadmium (II) and nickel (II) turned out to be about 0.85 and 0.95 mmol/g, respectively