title: Polyethyleneimine-grafted collagen fiber as a carrier for cell immobilization.
abstract: 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 5.3.1.5) 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 (K m) 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 (E a) 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.
authors.affiliation: Department of Biomass Chemistry and Engineering, Sichuan University, No. 24 South Section 1, Yihuan Road, Chengdu, 610065, People's Republic of China.
authors.forename: Deyi
authors.initials: D
authors.lastname: Zhu
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.forename: Xuepin
authors.initials: X
authors.lastname: Liao
authors.forename: Bi
authors.initials: B
authors.lastname: Shi
mesh_terms: D039903:Actinobacteria / Q000166:cytology*; D018914:Cells, Immobilized; D003094:Collagen / Q000737:chemistry*; D005976:Glutaral / Q000737:chemistry; D006207:Half-Life; D011094:Polyethyleneimine / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry
chemical_list: D011108:Polymers; D011094:Polyethyleneimine; D003094:Collagen; D005976:Glutaral