ISSN:
1432-0614
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Summary Treatment of Kluyveromyces cells with several polycations partially neutralized their negative charge, even after washing; chitosan at 0.5 mg/ml rendered the zeta potential positive. Adhesion of the cells to various supports (glass, polycarbonate, polystyrene) was promoted by treating the cells or the support with chitosan; this confirms the importance of electrostatic interactions in the adhesion process. When the support was treated, a dense and regular monolayer of adhering cells was obtained; when the cells were treated the adhering layer was more heterogeneous due to floc formation. Cell ghosts of K. lactis were prepared by CHCl3/ethanol permeabilization and glutaraldehyde treatment. Treating the ghosts with chitosan provided immobilization of 1.9 to 7.3×106 ghosts per cm2 according to the support; treating the support allowed to obtain 5.5 to 5.7×106 ghosts per cm2. The lactase activity of the immobilized ghosts was found to be comparable to that of ghosts in suspension, i.e. in the range of 0.9 to 2.2 U/mg dry cell weight, at 30°C, corresponding to 0.02 to 0.14 U/cm2 of support. A test in microreactor with a lactase solution showed that 50% of the initial activity was still found, after about 25 days of continuous operation at 30°C.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00451614
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