Biotechnological Journal of Environmental Microorganisms
Year:2012 | Volume:6 | Issue:2 (2)|Papers Count:8

Environmental pollution by toxic metals is a global problem. Most common physical and chemical methods such as sedimentation, chemical oxidation and reduction, and separation by reverse osmosis and membranes for biological uptake, limitations such as being inactive at low concentrations of pollutants, is expensive and not cost effective. Biological uptake for such a purpose can be a good alternative for large volumes of toxic metal pollution is low level. In this study, bacteria Bacillus sp. AEJ-89 isolated from Maranjab desert city of Kashan in Isfahan province as biological adsorbents for biological uptake of copper and nickel were used in a batch reactor. In the first stage adsorption kinetics of copper and nickel have been investigated. Equilibrium time of reaction was about 5 minutes. Adsorption isotherm data for copper and nickel by Bacillus was interpreted by the Langmuir equation. Release rates of copper and nickel from the bacteria by desorption agents such as nitric acid, hydrochloric acid, acetic acid, and EDTA has been investigated. To investigate the uptake of active and inactive of active and passive uptake of bacteria by autoclave, 2, 4-Dinitrophenol (DNP), Sodium azide (NaN3) was inactivated. The maximum adsorption of copper and nickel uptake by the bacteria, were, 0.85, 0.65 mmol/ g dry weight of the bacterial cell, respectively.

Hydrology and hydrobiology studies have indicated a relatively long history in the aquatic environments of Dams in Iran and the world planktonic investigation has considered a part of these researches. Up to now, any investigation has not done on Sattarkhan reservoir Dam. In this survey, in order to investigate phytoplankton density, activity and physiological role of non-biological factors associated with them and also evaluation of self-purification, the saprophyte flora and coliform bacteria in water in different seasons between ahar Sattar khan Dam in 1990 till 2009 from nine station for sampling in areas that include all biotopes, took place. Results showed that in winter, because the lake is covered with ice, the production resulting from phytoplankton action in the process of photosynthesis is blocked. In contrast, in summer because of favorable temperature and plenty of biogenic elements, activities of phytoplankton are abundant. While, the number of saprobes in spring and summer fall between 5 – 8.3 times less. It also became clear that the amount of coliform bacteria in the summer is due to presence of human and animal wastes, along with migration to the other regions is twofold. Compared to other seasons.

Expansion of industrial activities, mining and metal plating could release high amounts of heavy metals into seawater and marine sediment led to heavy metals resistant microorganisms. Due to important role of Streptomyces in production of secondary metabolites, enzymes and elements reduction ability, isolation of heavy metals (copper and mercury) resistant Streptomyces from marine sediments and coastal waters of Caspian Sea were studied. Marine sediments and water samples were collected from 5 coastal locations at a depth of 10, 20 and 30 cm aseptically. Starch Casein Agar and Kuster’s Agar were used for the isolation of Streptomyces and then biochemical testes like lipid, casein, starch and gelatin hydrolysis, nitrate reduction, carbohydrates utilization and so on carried out for identification of Streptomyces. Determination of heavy metals (Hg, Cu) resistant Streptomyces was performed with micro dilution and well diffusion methods. Also, amounts of heavy metals in different parts of coastal waters measured with atomic absorption spectrophotometer assay. A total of 41 Streptomyces isolated from coastal locations, 7 strains (17.07%) showed resistancy to copper 1000 mg/l and 4 strains (9.75%) to mercury. The strains including C9, D11 and E16 to 20mg/l and C2 to 40mg/l were mercury resistant. Because of existence of heavy metals (Hg, Cu) resistant Streptomyces in Caspian Sea probability can use them as well suited agents for bioremediation.

Regarding the high consumption of water in sugar industries, which leaves a wastewater of high organic load (COD), biodegradability of these wastes is of high importance, before releasing it to the environment. The main part of the Shahroud Sugar Plant’s wastewater is calcium carbonate slurry, which is a result of syrup refining process, and steam boilers’ drainage. Although the resulting wastewater has high organic materials, however, due to its high content of inorganics, an especially calcium and magnesium salt, its biodegradability (BOD5) is very low. In this study it was shown that by removing inorganic salts, especially calcium, by hydrogen cationic- exchange resin, and addition of urea and ammonium phosphate, 1 and 0.3 g/L respectively, the wastewater gained a suitable biodegradability. Other sources of inorganic nitrogen, like ammonium chloride, were not effective in increasing the biodegradability.

Nickel and Cadmium are among the heavy and toxic metals whose industrial usage lead to environment pollution extensively. One of the best procedures in removing of the toxic minerals in nature is using metal resistant bacteria. Therefore, determining the bacteria resistant to the toxic minerals is the first step in usage of them in bioremediation. In result industrial wastewater bioremediation is highly regarded as an economical and environmentally friendly option. In order to isolation and identification of resistant bacteria to nickel and cadmium, sampling was performed from wastewater in eight factories in the north of Iran (Guilan). Several bacterial isolates were separated on LB agar medium containing minimal concentrations of heavy metals, nickel (0.002 gr/plate) and cadmium levels (2.5 mg/plate). The primary metal resistant isolates that showed maximum resistance, nickel (0.2 gr/plate) and cadmium (20 mg/plate), were also separated. After microscopic examination, molecular identification of bacteria was performed by 16S rDNA PCR Sequencing. A total, 17 different species were identified which includes Staphylococcus epidermidis, Staphylococcus pasteuri, Planococcus spp., Brevundimonas diminuta, Bacillus licheniformis, Pseudomonas spp., Exiguobacterium spp., Micrococcus spp., Comamonas spp., Delftia spp., Chryseobacterium spp. Serratia spp., Acinetobacter spp. that showed the highest resistance to nickel (0.2 gr/plate) and cadmium (20 mg / plate).

Aspergillus spp are ubiquitous opportunistic moulds that cause both allergic and invasive syndromes. The genus comprises approximately 200 species, of which 18 have been associated with human disease. Glactomannan (GM) is an essential molecule in the life of the human opportunistic fungal pathogen Aspergillus fumigatus. GM is also produced in the host and is a well-known A. fumigatus antigen. The main aim of this study was identification of Galactomannoprotein, therefore A. fumigatus strain AF-293 was cultivated in Sabouraud’s liquid medium in three different conditions. After identification of Galactomannoprotein, samples were analyzed by sodium dodecyl sulfate polyacrylamide gel electrorhoresis (SDS-PAGE). GMPs stained with silver staining technique or electrotransferred to nitrocellulose. Serum samples from 15 patients were used through this study. Sera from patients were analyzed for the presence of antibody to A. fumigatus GMP by an indirect enzyme-linked immunosorbent assay (ELISA) method. Results illustrated that GMP had a molecular weight 60 kDa. In addition, ELISA results showed that GMP can interact with patients’ sera as an antigen.

Bacitracin as a polypeptide with antimicrobial properties produces by different Bacillus spp. that, they play an important role in medicine and veterinary. The aim of this research was optimizing nutrition and environmental conditions for optimal production of bacitracin by Bacillus licheniformis PTCC 1721 using one factor at time and Taguchi method. In this study the effects of different carbon and nitrogen sources, initial pH, inoculum size and and incubation times were evaluated. The results were showed the best carbon and nitrogen sources for bacitracin production were glucose, glumatic acid and peptone, respectively. The optimal pH and incubation period were pH=7 and 48 hours, respectively. The amount of produced bacitracin were 200.174 and 422.639 u/ml-1 before and after of media component optimization using taguchi method respectively. In the base of results, bacitracin production was increased about 2-fold after optimization.

Nanoparticles and Nano-composites play an important role in the life sciences. In this study, the antimicrobial activity of some kind of Nano composite alumina- silica- titania with silver Nano-particles in different concentrations was investigated. Five methods including Minimum Inhibitory Concentration, Agar well diffusion method, Agar disk diffusion method, shaker and effective toxicity of cell were utilized. To evaluate the antimicrobial activity of five different concentrations of nanoparticles on Escherichia coli, Bacillus subtilis and Candida albicans, were used. Results showed that, even at the highest concentration of alumina composite nanoparticles have been used, and the dispersion, the ability to kill microorganisms is studied, and the silver particles in the lowest concentration of microorganisms were bactericidal. Behalf, the toxicity characteristics of epithelial cells showed that, unlike the silver Nano-particles, alumina Nano composite for good biological compatibility can be used in medical science. The present study confirms this fact that antibacterial effects of silver nanoparticles is broad and effective but Nano-composite alumina inhibited microorganisms such as E. coli in limited range.