title: Microbial cell-based biosensor for sensing glucose, sucrose or lactose.
abstract: 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 beta-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.
authors.affiliation: Biotechnology Department, Technical University, Bratislava, Slovak Republic.
authors.forename: J
authors.initials: J
authors.lastname: Svitel
authors.forename: O
authors.initials: O
authors.lastname: Curilla
authors.forename: J
authors.initials: J
authors.lastname: Tkác
mesh_terms: D016947:Acetobacteraceae / Q000737:chemistry / Q000378:metabolism; D015374:Biosensing Techniques; D005780:Gelatin; D005947:Glucose / Q000032:analysis*; D007716:Kluyveromyces / Q000737:chemistry / Q000378:metabolism; D007785:Lactose / Q000032:analysis*; D008566:Membranes; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000378:metabolism; D013395:Sucrose / Q000032:analysis*
chemical_list: D013395:Sucrose; D005780:Gelatin; D005947:Glucose; D007785:Lactose