Mercury is one of the toxic elements and very harmful. The mercury exposure will mainly cause health effect, and the exposure can be in terms of dose, the age of person exposed, duration exposed route exposed, and duration of exposure. Mercury is one of the heavy metals of concern in Malaysia, found in wastewaters coming from oil refinery and petrochemical industries. Mercury and mercurial compounds are highly toxic contaminants in the aquatic systems and soils. The proper disposal of wastewater should be implemented with the Department of Environment of Malaysia (DOE), which is the mercury concentration should be 0.05 ppm for standard B in wastewater for people and environmental health. There are many types of mercury removal technology to reduce the concentration of mercury, such as chemical treatment, ion exchange, membrane filtration, adsorption, and bioremediation used for mercury removal in this study. This paper present the activity of enzyme from Pseudomonas putida (P. putida) is produced in the mercury treatment from petrochemical wastewater at optimum condition. P. putida growth at the optimum condition in the different mercury concentrations was observed. The conclusion of optimum condition concentration of mercury and shaker speed at 7 ppm is 41◦C and 180 rpm, respectively, with the ability to reduce 92.59% mercury concentration. During the processes of mercury removal, mercuric reductase was produced at a value of 56 kDa.

1. S. M. Wilhelm and N. Bloom, “Mercury in petroleum,” Fuel Processing Technology, vol. 63, no. 1, pp. 1–27, 2000. doi: https://doi.org/10.1016/s0378-3820(99)00068-5
2. M. Rebhun and N. Galil, “Technological strategies for protecting and improving the biological treatment of wastewater from a petrochemical complex,” Water Science and Technology, vol. 29, no. 9, pp. 133–141, 1994. doi: https://doi.org/10.2166/wst.1994.0461
   
3.  Environment Quality Act 1974. Environmental quality(sewage and industrial eftluents) regulations, 1979. [Online]. Available: https://bit.ly/2PyY9AZ
   
4.  P. Hajeb, S. Jinap, A. B. Fatimah, and B. Jamilah, “Methylmercury in marine fish from malaysian waters and its relationship to total mercury content,” International Journal of Environmental and Analytical Chemistry, vol. 90, no. 10, pp. 812–820, 2010. doi: https://doi.org/10.1080/03067310903131941
   
5.  S. Ghosh, A. M. Gifford, L. R. Riviere, P. Tempst, G. P. Nolan, and D. Baltimore, “Cloning of the p50 DNA binding subunit of NF-κb: Homology to rel and dorsal,” Cell, vol. 62, no. 5, pp. 1019–1029, 1990. doi: https://doi.org/10.1016/0092-8674(90)90276-k
6. A. A. B. M. Azoddein, R. B. M. Yunus, N. M. B. N. Sulaiman, A. B. B. Bustary, F. A. B. M. Azli, and S. B. C. Sayuti, “Effect of Mercury concentration on p. putida growth in Mercury removal,” Journal of Applied and Physical Sciences, vol. 3, no. 3, pp. 107–116, 2017. doi: https://doi.org/10.20474/japs-3.3.4
   
7.  P. Bunruk, D. Kantachote, and A. Sukhoom, “Isolation and selection of purple non-sulfur bacteria for phosphate removal in rearing water from shrimp cultivation,” Journal of Applied and Physical Sciences, vol. 3, no. 2, pp. 73–80, 2017. doi: https://doi.org/10.20474/japs-3.2.5
   
8.  P. B. Gundala, K. JayaKumar, and P. Chinthala, “Physiological and growth promoting characteristics of Pseudomonas putida isolated from forest litter of Tirumala hill forest,” International Journal of Research in Pure and Applied Microbiology, vol. 3, no. 1, pp. 14–16, 2013.
   
9.  P. Roya, R. Hadi, A. Hossein, and M. Vahedian, “Survey of wastewater stabilization pond potential in meeting environmental standards,” International Journal of Applied and Physical Sciences, vol. 1, no. 1, pp. 19–21, 2015. doi: https://dx.doi.org/10.20469/ijaps.50003
   
10.  A. D. Felske, W. Fehr, B. V. Pauling, H. Von Canstein, and I. Wagner-Döbler, “Functional profiling of mercuric reductase (mer A)
    genes in biofilm communities of a technical scale biocatalyzer,” BMC Microbiology, vol. 3, no. 1, p. 22, 2003.
    
11.  W. Zhang, L. Chen, and D. Liu, “Characterization of a marine-isolated mercury-resistant Pseudomonas putida strain SP1 and its potential application in marine mercury reduction,” Applied Microbiology and Biotechnology, vol. 93, no. 3, pp. 1305–1314, 2012. doi: https://doi.org/10.1007/s00253-011-3454-5
    
12.  V. Cabral, S. Znaidi, L. A. Walker, H. MartinYken, E. Dague, M. Legrand, K. Lee, M. Chauvel, A. Firon, T. Rossignol et al., “Targeted changes of the cell wall proteome influence Candida albicans ability to form single-and multi-strain biofilms,” PLoS Pathogens, vol. 10, no. 12, pp. 1–21, 2014. doi: https://doi.org/10.1371/journal.ppat.1004542
    
13.  A. Azoddein, R. Yunus, N. Sulaiman, A. Bustary, and F. Azli, “Mercury removal from petroleum based industries wastewater by P. Putida,” International Journal of Scientific & Technology Research, vol. 4, no. 6, pp. 32–39, 2015.