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Employing Response Surface Methodology for Optimization of Mercury Bioremediation by Vibrio parahaemolyticus PG02 in Coastal Sediments of Bushehr, Iran
Author(s) -
Jafari Seyed Ali,
Cheraghi Sama,
Mirbakhsh Maryam,
Mirza Roozbeh,
Maryamabadi Ammar
Publication year - 2015
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.201300616
Subject(s) - mercury (programming language) , bioremediation , vibrio parahaemolyticus , bacteria , response surface methodology , 16s ribosomal rna , vibrio , central composite design , chemistry , microbiology and biotechnology , environmental chemistry , biology , chromatography , genetics , computer science , programming language
Three bacterial species of PG01, PG02, and PG03 were isolated from coastal sediments of Bushehr (Iran) as mercury‐resistant bacteria. According to 16S ribosomal DNA gene sequence, the strains were identified as Vibrio natriegens , Vibrio parahaemolyticus , and Oceanimonas baumannii , respectively. Minimum inhibitory concentration test in the presence of HgCl 2 revealed that the strain PG02 was the most resistant one, which tolerated up to 45 mg L −1 Hg 2+ . Tracing the growth curves for the PG02 showed that when it is initially exposed to 5 mg L −1 Hg 2+ in the medium, only 10% of its natural growth is reduced, while it simultaneously succeeds to remove 90% of mercury. However, initially 10 mg L −1 Hg 2+ in the medium led to 30% growth inhibition and 80% mercury removal. According to a linear relationship between the growth inhibition percentage and the initial mercury concentrations, the median effective concentration was calculated as 21.84 mg L −1 for PG02. Central composite design under response surface methodology well proposed a model with high values of R 2 = 0.999 and adjusted R 2 = 0.998 which predicted the maximum mercury removal of 89.47% by PG02 under optimum pH of 7.2, temperature of 37.5°C and the initial mercury concentration of 5 mg L −1 .