Reference

Diffusion characteristics of substrates in calcium-alginate gel beads

Diffusion characteristics of substrates in calcium-alginate gel beads. Tanaka, Hideo; Matsumura, Masatoshi; Veliky, I. A. (Inst. Appl. Biochem., Univ. Tsukuba, Japan). Biotechnol. Bioeng., 26(1), 53-8 (English) 1984. CODEN: BIBIAU. ISSN: 0006-3592. DOCUMENT TYPE: Journal CA Section: 16 (Fermentation and Bioindustrial Chemistry) The diffusion characteristics of several substrates of varying mol. sizes into and from Ca alginate (I) [9005-35-0] gel beads in well-stirred solns. were investigated. The diffusion coeffs. (D) of substrates of mol. wt. <2 ′ 104, such as glucose [50-99-7], L-tryptophan [73-22-3] and a-lactalbumin into and from the gel beads agreed with those in the water system. They could diffuse freely into and from the gel beads without disturbance by the pores. Diffusion was also not disturbed by increasing the I concn. in the beads and the CaCl2 concn. used in the gel prepn. The diffusion of higher-mol.-wt. substances such as albumin, g-globulin and fibrinogen was very different. No diffusion into the gel beads was obsd., and only albumin was partly absorbed on the surface of the gel beads. Their values of D from the gel beads into their solns. were smaller than their values in the water system, but all could diffuse from the gel beads. The diffusion of high-mol.-wt. substrates was limited more strongly by the increase of I concn. in the gel beads than by the increase of the CaCl2 concn. used in the gel prepn. The capacity of I gel as a matrix of immobilization was discussed.

Production of vitamin B12 by living bacterial cells immobilized in calcium alginate gels

Production of vitamin B12 by living bacterial cells immobilized in calcium alginate gels. Yongsmith, Busaba; Chutima, Krisna (Fac. Sci., Kasetsart Univ., Bangkok, Thailand). J. Ferment. Technol., 61(6), 593-8 (English) 1983. CODEN: JFTED8. ISSN: 0385-6380. DOCUMENT TYPE: Journal CA Section: 16 (Fermentation and Bioindustrial Chemistry) Whole cells of Propionibacterium arl AKU 1251 were immobilized in a living state in Ca alginate [9005-35-0] gels. The vitamin B12 [68-19-9] prodn. and growth of immobilized cells could be increased by incubation of the entrapped cells in a medium contg. high concns. of C and N sources. The precursors of vitamin B12, CoSO4 and 5,6-dimethylbenzimidazole [582-60-5], together with a surfactant, Tween 80 [9005-65-6], markedly enhanced vitamin B12 prodn. The max. yield reached 20 mg/L.