Aa Javadi, A Mousavi, M Mohseni, S Mobasheri Zadeh,
Volume 2, Issue 2 (Autumn – Winter 2009[PERSIAN] 2008)
Abstract
Abstract Background and objectives: Air ionization (AI) may reduce the microbial content of the air 'and has bactericidal effects on some bacterial Strains, which is controversial. We conducted this study to evaluate the efficacy of Air ionizer in reducing the microbial content of air. Material and Methods: This experimental Study was carried out in Sadi Hospital of Isfahan. Two air ionizer were placed in two boxes. and the third box (Control) was empty. At the beginning of experiment and every 30 minutes up to three hours, we did air sampling in all groups. After taking the samples of every box, we incubated the samples and then performed colony counts and bacteriologic studies. Results: In all thirty-minute intervals, Colony Counts in all groups were lower than control group (P<0.05). 'Coagulase negative staphylococcus (CNS) was the most common bacteria isolated followed by Bacillus spp, Acinetobacter and Escherichia Coli, in control group, no colonization of Acinetobacter and E.coli is found in Air ionizer groups. Conclusion:Our findings qualitatively indicate that air ionization can reduce the microbial content of the air. Regarding the type of microbial air pollution and the amount of air cleaning needed, this method can be used solely or in combination with other air cleaning methods. Key words: air ionization, air cleaning air bacteria.
M Mohseni, F Khosravi, M Mohadjerani, Mj Chaichi,
Volume 8, Issue 3 (Autumn[PERSIAN] 2014)
Abstract
Abstract Background and Objectives: Contamination of environment to lead and copper is rising due to human activities. One of the best methods to remove heavy metals from the environment is bacterial remediation. This study aimed to isolate bacteria and investigate the mechanism of lead and copper bioremediation. Material and Methods: Heavy metal resistant bacteria were isolated from contaminated wastewater samples. The isolates with high resistance to lead and copper were selected for further studies and bioremediation was assessed by atomic absorption spectrophotometer. To determine the functional groups to remove metals, FT-IR was employed. In addition, plasmid curing was studied to determine the location of the genes that are resistance to heavy metals. Results: Ten bacterial isolates that are resistance to heavy metals were isolated. Among these, MKH3 with the highest remediation activity removed %90 lead and %92 copper from the growth medium. The absorption mechanism of MKH3 indicated that the functional groups such as carboxyl, amide, carbonyl and hydroxyl were most effective for removal of heavy metals from the growth medium. The results revealed that heavy metal resistant genes may be located on plasmid DNA. Furthermore, molecular identification demonstrated that MKH3 was similar to Enterobacterhormaechei with 98% homology. Conclusion: Bacterium isolated from a contaminated site showed the ability to remove a high amount of lead and copper. Thus, MKH3 could be useful for the bioremediation of heavy metals, particularly lead and copper, from industrial wastewater and contaminated sites. Keywords: Biosorption, Bacteria, Lead, Copper, FT-IR
