Variations of binding, washing, and concentration of imidazole on purification of recombinant Fim-C Protein Salmonella typhi with Ni-NTA Resin

Typhoid fever is an endemic disease in Indonesia. Prevention of typhoid fever can be done by administering vaccines. It is known that one of the raw materials for vaccines is a recombinant protein. This study aims to obtain information on the optimum conditions for purification of Salmonella typhi Fim-C recombinant protein with Ni-NTA resin as vaccine raw material. The three main stages of the purification process in this study were binding, washing, and elution of S. typhi Fim-C recombinant proteins. The binding and washing variations of recombinant proteins were carried out twice, four times and six times, while the elution process was carried out at imidazole concentrations of 200 mM, 250 mM, and 300 mM. Purification with a binding process four and six times gave almost the same intensity of S. typhi Fim-C protein bands. Whereas protein was elution at an imidazole concentration of 300 mM showed higher band instability. The results of characterization using SDS-PAGE and analysis using software ImageJ gel analysis showed that the longer the incubation time and the repetition of the binding process, the more protein bound to the resin. Furthermore, the more washing processes are obtained the purer proteins. Based on the data obtained it can be concluded that the purification of the S. typhi Fim-C recombinant protein was optimum at a four-time binding process, six times washing and a 300 mM imidazole concentration. These results are expected to be the basis for recombinant protein refining on a pilot scale and industry scale in better vaccine preparation.