title: Offline glucose biomonitoring in yeast culture by polyamidoamine/cysteamine-modified gold electrodes.
abstract: This article deals with the use of pyranose oxidase (PyOx) and glucose oxidase (GOx) enzymes in amperometric biosensor design and their application in monitoring fermentation processes with the combination of flow injection analysis (FIA). The amperometric studies were carried out at -0.7 V by following the oxygen consumption due to the enzymatic reactions for both batch and FIA modes. Optimization studies (enzyme amounts and pH) and analytical parameters such as linearity, repeatability, effect of interference, storage, and operational stabilities have been studied. Under optimized conditions, for the PyOx-based biosensor, linear graph was obtained from 0.025 to 0.5 mM glucose in phosphate buffer (50 mM) at pH 7.0 with the equation of y = 3.358x + 0.028 and R(2) = 0.998. Linearity was found to be 0.01-1.0 mM in citrate buffer (50 mM and pH 4.0) with the equation of y = 1.539x + 0.181 and R(2) = 0.992 for the GOx biosensor. Finally, these biosensor configurations were further evaluated in a conventional flow injection system. Results from batch experiments provide a guide to design sensitive, stable, and interference-free biosensors for FIA mode. Biosensor stability, dynamic range, and repeatability were also studied in FIA conditions, and the applicability for the determination of glucose in fermentation medium could be successfully demonstrated. The FIA-combined glucose biosensor was used for the offline monitoring of yeast fermentation. The obtained results correlated well with HPLC measurements.
authors.affiliation: Department of Biochemistry, Faculty of Science, Ege University, 35100 Bornova-Izmir, Turkiye.
authors.forename: Merve
authors.initials: M
authors.lastname: Yuksel
authors.forename: Mehriban
authors.initials: M
authors.lastname: Akin
authors.forename: Caner
authors.initials: C
authors.lastname: Geyik
authors.forename: Dilek Odaci
authors.initials: DO
authors.lastname: Demirkol
authors.forename: Caglar
authors.initials: C
authors.lastname: Ozdemir
authors.forename: Arne
authors.initials: A
authors.lastname: Bluma
authors.forename: Tim
authors.initials: T
authors.lastname: Höpfner
authors.forename: Sascha
authors.initials: S
authors.lastname: Beutel
authors.forename: Suna
authors.initials: S
authors.lastname: Timur
authors.forename: Thomas
authors.initials: T
authors.lastname: Scheper
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D003543:Cysteamine; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D005285:Fermentation; D017022:Flow Injection Analysis; D005947:Glucose / Q000032:analysis*; D006046:Gold; D011073:Polyamines; D015003:Yeasts / Q000166:cytology / Q000378:metabolism*
chemical_list: C531249:Poly(amidoamine); D011073:Polyamines; D003543:Cysteamine; D006046:Gold; D005947:Glucose