title: Alginate/bacterial cellulose nanocomposite beads prepared using Gluconacetobacter xylinus and their application in lipase immobilization.
abstract: Alginate/bacterial cellulose nanocomposite beads, with well-controlled size and regular spherical shapes, were prepared in a simple manner by entrapping Gluconacetobacter xylinus in barium alginate hydrogel beads, followed by cultivation of the entrapped cells in culture media with a low sodium ion concentration. The entire surface of the alginate hydrogel beads containing the cells was covered with cellulose fibers (∼30nm) after 36h of cultivation. The cellulose crystallinity index of the alginate/bacterial cellulose beads was 0.7, which was slightly lower than that of bacterial cellulose prepared by cultivating dispersed cells. The water vapor sorption capacity of the alginate/bacterial cellulose beads increased significantly from 0.07 to 38.00 (g/g dry bead) as cultivation time increased. These results clearly indicate that alginate/bacterial cellulose beads have a much higher surface area, crystallinity, and water-holding capacity than alginate beads. The immobilization of lipase on the surface of the nanocomposite beads was also investigated as a potential application of this system. The activity and specific activity of lipase immobilized on alginate/bacterial cellulose beads were 2.6- and 3.8-fold higher, respectively, than that of lipase immobilized on cellulose beads. The alginate/bacterial cellulose nanocomposite beads prepared in this study have several potential applications in the biocatalytic, biomedical, and pharmaceutical fields because of their biocompatibility, biodegradability, high crystallinity, and large surface area.
authors.affiliation: Department of Microbial Engineering, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Microbial Engineering, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Saerom
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Organic and Nano System Engineering, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Hyungsup
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Microbial Engineering, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Hyung Joo
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Microbial Engineering, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Yung-Hun
authors.initials: YH
authors.lastname: Yang
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea.
authors.forename: Yong Hwan
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Bio & Chemical Engineering, Hongik University, Sejong 339-701, South Korea.
authors.forename: Sang-Kyu
authors.initials: SK
authors.lastname: Jung
authors.affiliation: Texas A&M AGRILIFE Research & Extension Center, Texas A&M University, Stephenville, TX 76401, USA; Office of Sponsored projects, Tarleton State University, Stephenville, TX 76401, USA.
authors.forename: Eunsung
authors.initials: E
authors.lastname: Kan
authors.affiliation: Department of Microbial Engineering, Konkuk University, Seoul 143-701, South Korea. Electronic address: sanghlee@konkuk.ac.kr.
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry; D041822:Gluconacetobacter xylinus / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D008049:Lipase / Q000737:chemistry*; D053761:Nanocomposites
chemical_list: D000464:Alginates; D004800:Enzymes, Immobilized; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D002482:Cellulose; D008049:Lipase
keywords: Alginate; Bacterial cellulose; Bead; Immobilization; Lipase; Nanocomposite