Overproduction and Purification of Organomercuric Lyase (MerB) from Mercury-resistant Bacteria Pseudomonas aeruginosa Isolate 4B2

Mercury is a very toxic element even though there is very little concentration in the body. Although all chemical forms of mercury are toxic, public health attention is focused on organic mercury which is the most toxic form of mercury. Organic mercury can, however, be detoxified by organomercuric lyase (MerB) protein derived from mercury resistant bacteria. This study aims to overproduce of MerB protein by transforming merB gene into E. coli BL-21(DE3). Nucleotide sequence of merB gene of mercury resistant bacteria Pseudomonas aeruginosa isolates 4B2, optimized by using gene program designers (www.dna20/com) then commercially synthesized and cloned in pET16b expression plasmid vector. Plasmid pET16b_merB (syntetic gene) was transformed into E. coli BL21(DE3) to produce MerB protein recombinant, induced with isopropyl-β-D-thiogalactopyranoside (IPTG) and purified by imidazol. Overproduction and purification of MerB protein was successfully performed in E. coli BL21 mediated by plasmid pET16b, resulting MerB protein with a molecular weight of 25.6 kDa, with the optimum at 37°C incubation temperature, incubation time of 3 hours and 0.1 mM IPTG induction. MerB protein obtained can be used in further research on the enzymatic detoxification of organic mercury.