Green chemical method was applied to synthesize nanoparticles using recombinant
bromelain. Among the numerous applications of recombinant bromelain, there is still no research
on nanoparticles synthesis which encourages its utilization in this study. Four chemicals which are
copper (II) chloride dihydrate (CuCl2.2H2O), cerium nitrate hexahydrate (Ce(NO3)3.6H2O), sodium
selenite (Na2SeO3), and iron (III) chloride hexahydrate (FeCl3.6H2O) were selected to be screened
for the suitability in nanoparticles biosynthesis by recombinant bromelain. The nanoparticles
formed were characterized by using UV-visible absorption spectra. The biosynthesis process then
was optimized by varying the centrifugation speed, temperature, and time to get the maximum
absorption and weight of nanoparticles through central composite design (CCD) tool. Only
CuCl2.2H2O showed a positive result for the screening process which was represented by the
formation of colloidal solution and a maximum absorption at 580 nm. Thus, optimization was
carried out for this chemical. Based on the optimization model, maximum absorption and weight
were predicted at 67.5°C, 2 hrs, and 9,600 rpm. These optimal conditions were validated by
repeating the biosynthesis process. The absorption and weight of the nanoparticles depended on the
reaction of the chemical with recombinant bromelain. 3D plots showed that the optimal condition
for high responses mostly depends on temperature and time.