Bacterial strains diversity in contaminated soils and their potential for bioremediation of total petroleum hydrocarbons in south west of Iran.

Purpose: The main purpose of this research was investigating of bioremediation potential oily contaminated soils using native bacterial strains in an oil field. Methods: In this research, total bacterial consortium were identified in oily soils with sandy loam texture as case and non-contaminated soils as controls during six months. The dominant strains present on contaminated soil were identified by DNA extraction using 16S rDNA gene sequencing via NGS technique and compared with bacteria present in non-contaminated soil as control samples. Furthermore, quantitative variations of bacterial count along with total petroleum hydrocarbons (TPH) removal was performed in oily (case) samples to investigate the relation between TPH removal and changes in bacterial density. The TPH values were determined with gas chromatography equipped with a flame ionization detector (GC-FID). Results: The dominant identified bacteria in oily soil were as follows: Halomonas, Moraxellaceae, Thalassobacillus, Zhihengliuella and Enterobacteriaceae which varied significantly from those identified in control soil. The bacterial diversity was higher in contaminated soil and a TPH removal of 50.9% was observed over a period of six months monitoring. Conclusion: Indigenous bacteria in oil-contaminated soils of an oilfield in south west of Iran were found to be able to degrade Total Petroleum Hydrocarbons. Our results showed that bioremediation of oil-contaminated soils can be implemented without need to amplification of heterogeneous bacteria. Considering sandy loam texture of soil samples, the identified strains of bacteria could be introduced as sufficient consortium for biodegradation of this soils with similar texture.

Estimating greenhouse emissions from sanitary landfills using Land-GEM and IPCC model based on realistic scenarios of different urban areas: a case study of Iran.

This study examined the emission of greenhouse gases from municipal solid waste disposal centers in different regions of Iran based on different scenarios. Assuming landfill site opening in 2012 and considering the 20-year plan period for its usage, the amount of wastes entering the landfill site was calculated for 2012-2032. For calculating the production of methane (CH4) and other gases during different years of the project, Land-GEM and IPCC model were used. We defined 9 scenarios for these two models based on the growth rate of population and waste generation. The results revealed that the lowest amount of gas emission in nine scenarios by Land- GEM model was related to non-methane organic compounds (NMOCs). According to the results obtained, the total emissions of greenhouse gases from sanitary landfills for Iran in 2032 were 3,844,000 Mg/year, the largest and lowest amounts of gas emission were related to Tehran region, 860,400 Mg/year, and the South Coast area of the country,138,200 Mg/year, respectively. The major section of the gas production in both landfills was related to greenhouse gas and carbon dioxide emissions. The difference in gas production in the studied regions was due to differences in the percentage of moisture and organic compounds.

Comparison of performance and efficiency of four methods to extract genomic DNA from oil contaminated soils in southwestern of Iran.

The wide spectrum of oil industry activities caused soil contaminants, as environmental concern in many areas of the world. Bioremediation of oily soils, as biological approach done by bacteria and fungi, is very important to eliminate this pollution. In this study four different metagenomic protocols for DNA extraction has been tested in order to sequence and identify the native bacterial species involved in remediation of oily soils. In this regard, 3 manual methods and a soil DNA extraction kit are used. In manual protocol, physical processes including the addition of silica beads and freezing samples by liquid nitrogen, chemical methods such as treating the lysozyme, and lysis buffer and proteinase K as biochemical methods were utilized for optimal extraction. Quality and quantity of the extracted DNA analyzed using Agarose gel electrophoresis and Picodrop respectively. Then, the 16S rdna gene of bacteria amplified through universal primer for preparing a genomic library by PCR. Results showed that the highest concentration and quality of extracted DNA was obtained by protocol D which was about 135 µg/ul and 260/230 = 2.2 respectively. Moreover, 500 bp fragment amplified perfectly by using DNA extracted through protocol D in the PCR test. Therefore, protocol D can be used as an appropriate and effective way in order to study the microbial population of oily soils using direct extraction of DNA.