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Polyethyleneimine-grafted collagen fiber as a carrier for cell immobilization
- Zhu, Deyi, Li, Xia, Liao, Xuepin, Shi, Bi
- Journal of industrial microbiology & biotechnology 2015 v.42 no.2 pp. 189-196
- Microbacterium arborescens, activated carbon, anion exchange resins, biopolymers, collagen, cross-linking reagents, fructose, glucose, glutaraldehyde, half life, immobilized cells, industrial microbiology, isomerization, xylose isomerase
- Collagen fiber (CF), an abundant natural biopolymer, features many favorable properties that make it a potential carrier for cell immobilization. In the present investigation, CF was grafted with polyethyleneimine (PEI) using glutaraldehyde (GA) as the cross-linking agent, resulting in the formation of a novel CF based carrier (CF-PEI). The properties of CF-PEI as a carrier were evaluated by the immobilization of Microbacterium arborescens (CICC 20196), which has glucose isomerase (EC 220.127.116.11) activity. It was found that M. arborescens cells immobilized on CF-PEI exhibited higher glucose isomerization than those using activated carbon or anion exchange resin as the carriers. The Michaelis constant (Kₘ) of the isomerization reaction for the CF-PEI-immobilized M. arborescens cells was 0.528 mol/L, which was slightly higher than that of free cells (0.473 mol/L). In addition, the apparent activation energies (Eₐ) of free and immobilized cells on CF-PEI were almost the same at 60 kJ/mol. In an isomerization reaction of glucose to fructose in a fixed-bed reactor, CF-PEI-immobilized M. arborescens cells showed appreciable activity and operational stability. The corresponding isomerization ratio was as high as 41 % for 20 days, and the half-life was about 40 days.