جستجوی مقالات مرتبط با کلیدواژه « باکتری هالوفیل » در نشریات گروه « زیست شناسی »

  Today, the ability to produce hydrolases enzyme that are active in high salt concentrations is considered a new approach to the use of halophilic bacteria in biotechnology. The aim of this study was the screening and isolation of extracellular lipase producing halophilic bacteria Marinobacter sp. S-14 isolated from Badab-e Surt Hypersaline spring. In this experimental study, 42 pure bacterial colonies were isolated from different samples of water, soil, sediment, and sludge from a hypersaline spring with a screening technique on the specific culture medium of halophilic bacteria. The isolate S-14, which showed the highest lipase activity, was selected for the identification by biochemical methods and 16S rRNA gene analysis. In order to optimize the growth conditions of the isolate, considering the maximum time of bacterial growth (72 hours), temperature, salt concentration, pH, carbohydrate, and amino acid intake were examined. The results were edited by Chromas pro 2.1.1 software, and compared with EzTaxon database. Strains that were more similar to the isolate were identified. Sequence analysis of 16S rRNA were performed by BioEdit 7.1.9, Clustal-2X 2.1, and MEGA 6, and the phylogenetic tree was drawn by the neighbor joining algorithm. The isolate S-14 had 99% similarity to Marinobacter flavimaris and Marinobacter adhaerens. The isolate had optimum growth in 5% NaCl concentration, 35°C, and 7.0 acidity. The isolate S-14 can be an appropriate candidate to produce extracellular lipase enzyme and can utilize Fructose and Phenylalanine as a sole source of carbon and energy.

Chemolithotrophic bacteria have an important role in the biogeochemical cycle in natural ecosystems. For instance, the oxidative part of the sulfur cycle is handled by sulfur-oxidizing bacteria. Moreover, these bacteria have an important role in various industrial fields including bioleaching. The aim of this study was isolation and identification of chemolithotrophic sulfur-oxidizing bacteria from the Namakdan cave Qeshm, Iran.
In this cross-sectional study, after sampling from the Namakdan cave in Qeshm and transferring the samples (salt, water, and sediment) to the lab, sample inoculation into enrichment media was carried out with three concentrations of NaCl. Following pH and temperature measurement, samples were transferred into solid and two-phase media. Further characterization of the isolates was performed using 16S rRNA gene amplification. Further analysis was performed to characterize the autotrophic or heterotrophic features of the isolates. Biomass was examined using classical turbidity method.
Totally, 39 strains were isolated from samples, based on differences in primary features such as colony form or growth rate. A total of 5 isolates were selected for further studies. Phylogenetic analysis showed that these isolates belong to Halothiobacillus genus.
Due to 30% salinity and neutral pH of this cave, isolation of chemolithotrophic sulfur-oxidizing bacteria was limited to few genera. Chemolithotrophic bacteria have longer growth time in comparison to heterotrophic ones, increasing generation time to 30 days.