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Biotechnology and Applied Biochemistry (1998) 27, (153–158) (Printed in Great Britain)

Microbial cell-based biosensor for sensing glucose, sucrose or lactose

Juraj vitel, Ondrej urilla and Jan Tká

Biotechnology Department, Technical University, Radlinskeho 9, 81237 Bratislava, Slovak Republic

Correspondence: Juraj vitel, Biotechnology Department, Technical University, Radlinskeho 9, 81237 Bratislava, Slovak Republic

Biosensors for the determination of glucose, sucrose and lactose were based on a Clark-type oxygen electrode covered with a membrane containing microbial cells. The glucose-sensing membrane was prepared with intact cells of Gluconobacter oxydans immobilized in gelatin cross-linked with glutardialdehyde. The disaccharide-sensing membranes were prepared by co-immobilization of G. oxydans with cells of Saccharomyces cerevisiae containing invertase for sucrose determination and with permeabilized cells of Kluyveromyces marxianus containing b-galactosidase for lactose determination. The strain of G. oxydans that we used was able to oxidize both anomers of glucose at the same rate; there was therefore no need for mutarotase co-immobilization in disaccharide-sensing membranes. The sensitivity of glucose sensor was 50 nA/mM, the range of the calibration curve was 0–0.8 mM, the response time was 2 min, and the response after 1 week of storage was 62% of the initial response. The parameters of the disaccharide sensors were similar: linear range of calibration curve up to 4 mM, response time 5 min. The activities of the sensors after 1 week of storage at ambient temperature were in the range 50–65% of the initial activity.

Received 30 May 1997/6 November 1997; accepted 19 November 1997

© 1998 The International Union of Biochemistry and Molecular Biology