JOURNAL OF MICROBIAL WORLD
Year:2011 | Volume:4 | Issue:1-2 (10)|Papers Count:8

Background and Objective: Jarosite is one of the limiting factors for recovery of copper from copper sulfide minerals. This study aimed to evaluate the influence of concentration of ferrous sulfate, pH and temperature on the jarosite formation during the sulfide ore bioleaching of Sarcheshmeh copper mine.Material and Methods: In this study, samples were collected from the depot crushing heap bioleaching site of Sarcheshmeh Copper Mine. The bioleaching experiments were performed in 500 ml flasks, containing 10% solids of sulfide ore (w/v), pulp (200 ml), the 9K culture medium, bacteria inoculation (10% v/v ofAcidithiobacillus ferrooxidans). The flask were shaked at 130 rpm throughout incubation.Results: Our results showed that increase in pH and concentration of ferrous sulfate facilitate rate of ferric iron precipitation. Maximum precipitation rate of ferric was achieved in 50 g/l of sulfate concentration, temperature 32 oC and pH 2/2. According to XRD and FTIR analysis of Bioleaching residue, the produced ferric precipitations are often potassium and ammonium jarosite.Conclusion: With regard to the optimal conditions in this study in terms of pH, temperature and concentration of ferrous sulfate it is possible to regulate Jarosite formation through bioleaching process and to increase the production of copper efficiency from copper sulfide ores.

Background and Objective: Proteases are an important group of industrial enzymes, which are widely used in different industries such as detergent, leather tanning, pharmaceutical, and food industries.The aim of this study was to immobilize Bacillus licheniformis cells in calcium alginate beads and study of its effects on the amount of alkaline protease production. Effects of several different conditions on stability of the beads were also examined.Material and Methods: Bacillus licheniformiscells were immobilized in calcium alginate beads and were used for production of alkaline protease. The amount of enzyme production was compared in immobilized and free-cell fermentation. Effect of stuffing rate (%) on the enzyme production was studied.Optimum pH and temperature of enzyme activity were also determined. Furthermore, effects of pH, curing time and treating the beads by glutaraldehyde on stability of the beads were examined.Results: In this study the amount of production and productivity of protease in immobilized cells state showed an increase of 74% and 54% in comparison to free cells state, respectively. The highest amount of the production of the enzyme was obtained in stuffing rate of 5% (v/v). Optimum pH and temperature of the enzyme activity were determined 8 and 65oC, respectively. The highest stability of the beads was observed at curing time of 1 hour at pH of 7.4. Treating the beads by glutaraldehyde was detrimental to their stability.Conclusion: Use of immobilized cells of Bacillus licheniformis in calcium alginate beads on the one hand, can increase productivity of the alkaline protease in comparison to free cells method, and on the other hand, reduces the cost of the enzyme production because of eliminating the need of preparation of inoculum for the new batches.

Background and Objective: Metallic green sheen and lactose fermentation has been used for identification and differentiation of E. coli from other Enterobacteriaceae in laboratories for many years.However, these methods defect to accurate diagnosis of E. coli. This study employed lamB gene PCR amplification to distinguish E. coli and Shigella from other Enterobacteriaceae isolated from clinical samples and surface waters, collected in Babol, Iran.Material and Methods: In this cross-sectional study, 100 clinical samples from patients attending health centers and 30 surface water samples were gathered in Babol. All samples were grown on blood agar and Eosin methylene blue. After first biochemical identification, DNA of the samples were extracted and lamB gene was amplified using the PCR reaction.Results: After cultivation of the samples on blood agar and eosin methylene blue media and biochemical identification of the strains, it has been shown that all 40 isolated E. coli and 30 Shigella carry the lamB gene. However, none of the Salmonella and Klebsiella strains showed the related band.Conclusions: According to the findings of this study, investigation of lamB gene is an appropriate method for initial isolation of E. coli and Shigella from other Enterobacteriaceae.

Background and objective: Newcastle is an acute and contagious disease in poultry that has irreparable economic detriments in the poultry industry. Due to many deaths in broiler chicken flocks, it is vital to detect and characterize the viral circulation. The aim of this study was to isolation and pathotyping of Newcastle virus by RT-PCR and MDT (Mean death time) methods in broiler chickens in Fars province.Material and Methods: In this study 300 tracheal tissue and cloacal swab samples from 30 infected poultry farms with a high mortality and respiratory disease were collected in Fars province. The samples were inoculated in the allantoic cavities of 9-11-day-old embryonated chicken eggs. After 72 hours incubation, the allantoic fluids were tested by hemagglutination, RT-PCR and MDT methods for the present of Newcastle virus and their pathotyping.Results: 10 out of total samples investigated by molecular method showed a 535bp amplification band fragment and were identified as Newcastle viruses. Also, among these samples, velogenic, mesogenic and lentogenic strains identified in 6, 3 and 1 sample respectively by MDT method.Conclusion: Based on isolation of velogenic and mesogenic viruses in broiler chickens flocks, it is essential to continues survey vaccine strains and their effectiveness.

Background and Objective: Cytomegalovirus leads to severe infection in individuals with immune deficiency and recipient of blood and its production. Infected blood reception, and haemodialysis are some of the risk factor factors in primary infection of cytomegalovirus. In this case-control study, positiveepidemiological of active and passive cytomegalovirus infection were investigated in haemodialysis patients and control group.Material and methods: Blood serums of 43 haemodialysis patients and 43 healthy controls, who were similar to the patients in terms of sex and age, were investigated for determination of specific anti IgG and IgM of cytomegalovirus.Results: Data revealed that 39 haemodialysis patient (69.90%) were positive for anti- IgG CVM and 8 haemodialysis (18.60%) were positive for anti-IgG CMV (active infection with cytomegalovirus) while active infection with cytomegalovirus in control group had significant difference with patient group (36.2%).Conclusion: Cytomegalovirus cause severe infection in haemodialysis patients, and the rate of infection is directly relatd totransfusion repetitions.

Background and Objectives: Dominant sclerectinian and soft corals contain the symbiotic single cell called zooxanthellae which have important role in preparing organic material for coral requirements.The coral reefs of this area in the gulf are always under effects of environmental conditions, such as subtropical latitude, temperature and salinity variations, changing symbiotic zooxanthellae. The aim of this study was identification of Symbiodinium clades and presence of clade D in sclerectinian and soft corals of Larak island by molecular methods.Materials and Methods: Three soft coral species and five sclerectinian coral species were collected from north and north east of Larak island, respectively. After DNA extraction, partial 28S ribosomal DNA of Symbidinium were amplified by polymerase chain reaction (PCR). Then PCR products were analyzed by phylogenetic analyses of the partial 28S ribosomal sequence.Results: To follow amplification of 28S large ribosomal subunit gene, the 780 bp PCR products were sequenced and were compared to the gene bank. The results showed that all the symbiotic clades of soft corals in Larak Island belonged to clade D.Conclusion: Dominance of clade D in sclerectinian and soft corals in Larak island due to of high temperature in the Persian Gulf and unstable condition of Hormoz strait is normal and natural.