Immobilization of a recombinant thermostable esterase (Pf2001) from Pyrococcus furiosus on microporous polypropylene: Isotherms, hyperactivation and purification

In this study, a recombinant thermostable esterase (Pf2001Δ60) from the hyperthermophilic archaea Pyrococcus furiosus was immobilized on microporous polypropylene (Accurel MP 1000). The adsorption was rapid, with 90% total protein and esterase activity being retained in the first 15 min. No desorption of the enzyme was detected in a time course of 180 min after immobilization, which indicates an intense enzyme–support interaction. The adsorption isotherms from the raw protein extract were determined by total protein quantification and esterase activity in the adsorption medium. Two distinct behaviors were observed: For total protein, the experimental data adjusted well to the Langmuir model (qm = 35.3 mg g−1 and Ka = 16.1 mL mg−1), indicating the formation of a monolayer; while the experimental data for esterase activity correlated better with the multilayer Langmuir model (qm = 4.4 U/g, Ka = 2223.7 mL U−1 and Kaa = 25.7 mL U−1), indicating the possible formation of a bilayer. Effect of enzyme immobilization on activity (hyperactivation) was evaluated by retention activity parameter (R%). This parameter was dependent of the protein/support ratio at the beginning of the immobilization process. Two hundred and thirty-seven percent hyperactivation was observed when the protein/support ratio was 18 mg/g protein. Furthermore, the immobilization process by means of selective adsorption permitted the purification of the esterase from P. furiosus in a single step.