초록
<P>A viable approach for methanol production under ambient physiological conditions is to use greenhouse gases, methane (CH<SUB>4</SUB>) and carbon dioxide (CO<SUB>2</SUB>), as feed for immobilized methanotrophs. In the present study, unique macroporous carbon particles with pore sizes in the range of ∼1-6 μm were synthesized and used as support for the immobilization of <I>Methylocella tundrae</I>. Immobilization was accomplished covalently on hierarchical macroporous carbon particles. Maximal cell loading of covalently immobilized <I>M. tundrae</I> was 205 mg<SUB>DCM</SUB> g<SUP>-1</SUP> of particles. Among these particles, the cells immobilized on 3.6 μm pore size particles showed the highest reusability with the least leaching and were chosen for further study. After immobilization, <I>M. tundrae</I> showed up to 2.4-fold higher methanol production stability at various pH and temperature values because of higher stability and metabolic activity than free cells. After eight cycles of reuse, the immobilized cells retained 18.1-fold higher relative production stability compared to free cells. Free and immobilized cells exhibited cumulative methanol production of 5.2 and 9.5 μmol mg<SUB>DCM</SUB><SUP>-1</SUP> under repeated batch conditions using simulated biogas [CH<SUB>4</SUB> and CO<SUB>2</SUB>, 4:1 (v/v)] as feed, respectively. The appropriate pore size of macroporous particles favors the efficient <I>M. tundrae</I> immobilization to retain better biocatalytic properties. This is the first report concerning the covalent immobilization of methanotrophs on the newly synthesized macroporous carbon particles and its subsequent application in repeated methanol production using simulated biogas as a feed.</P><BR>[FIG OMISSION]</BR>