|
چکیده
|
Most oil pollution in marine environments is the result of routine shipping operations, coastal oil re?nery ef?uents, industrial and municipal waste disposal, oil-spills caused by tanker accidents and blow-outs from off-shore oil-well platforms. crude oil was accumulated and remained for a long time in the coastal area. The problem of oil pollution is particularly acute in an oil-producing area like the Persian Gulf. In this research, two marine sponges consist of Dictyonella sp and Pachychalina sp were collected from Kharko Island and Dayyer port in coast of Persian gulf by scuba diving at 10-15m depth. The internal mesohyl was homogenized and aliquot was cultured on various isolation media including marine agar, Emerson agar and nutrient agar and then symbiosis microorganisms were isolated and purified. Yield colonies were screened by emulsification index and growth rate in media containing crude oil. 10 strains from 22 isolate that have maximum growth rate and emulsification index were selected for further researches. Those isolates were cultured in minimal salt medium (MSM) with 1% crude oil and elimination rate of crude oil was assessment by spectrophotometer at 420nm and dry weight. Strain number 3 that showed maximum growth rate, minimum absorption and dry weight was selected for GC MASS analysis. Elimination rate of crude oil was obtained 97/28%. Also design experiment by Taguchi method was done for isolate number 3 and effect of carbon source, nitrogen source, pH and salinity was assessment in three levels. The optimum biodegradation base of taguchi results observed in medium without carbon source, NH4Cl as nitrogen source, 0/5% salinity and pH=6/5. Isolates were identified by using 16SrRNA gene and DNA sequences that obtained from the isolates bacteria were compared with other bacterial sequences using NCBI BLAST. Distance and phylogenetic tree were constructed in Mega6 version.Crude oil degraders isolated was belong genus of Georgenia satyanarayanai، Pseu
|