The innovation engine for new materials

Nilufar Karimi

Nilufar Karimi

University: 

University of California, Santa Barbara

Major: 

Chemical Engineering

Site Abroad: 

Chalmers Institute of Technology, Gothenburg, Sweden

Mentor(s): 

Milene Zezzi Do Valle Gomes

Faculty Sponsor(s): 

Anders Palmqvist

Project Title: 

ENZYME IMMOBILIZAITON ON MODIFIED MESOPOROUS SILICA SURFACE FOR THE CONVERSION OF CO2 INTO METHANOL

Project Description: 

Mesoporous materials have been extensively studied as a solid support for biocatalysts and bioseparations due to its high stability and activity. In particular, this project focuses on mesoporous cellular foam (MCF) silica as a suitable material for the immobilization of alcohol-, formaldehyde-, and formate dehydrogenase enzymes. MCF silica was synthesized and modified by attachment of the following organic groups to investigate the enzyme-surface interaction for optimal enzyme immobilization: chloromethyl, mercaptopropyl, octyl, and aminopropyl. Charge, hydrophobicity, steric hindrance, and polarity affect the favorability of enzyme-surface interaction. In characterizing pore structure, Brunauer-Emmett-Teller (BET) method and transmission electron microscopy (TEM) reported the surface area and confirmed the expected spherical shape of MCFs respectively. Fourier transform infrared spectroscopy (FTIR) determined whether the functionalization of the organic groups occurred on the silica surface. The concentration of the enzyme absorbed on the modified silica surfaces were measured in pH of 5.7 and 7.0 (≥pI of enzyme) by UV-VIS spectroscopy. At reaction conditions of pH ~6.5 and 37˚C, the enzyme concentration on the surfaces were examined for leakage. Conclusively, it appears the octyl-modified silica provides a high affinity for immobilization of each enzyme with little to no leakage for two cycles, while aminopropyl-modified silica provides a low affinity. The results may advance the understanding of co-immobilized enzymatic activity on mesoporous silica and applicability in the reduction of CO2 to methanol. The goal is to develop a bioreactor to recycle greenhouse gases into renewable fuel and minimize energy and costs.