Offline Glucose Biomonitoring in Yeast Culture by Polyamidoamine/Cysteamine-Modified Gold Electrodes

WOS: 000289431600028PubMed ID: 21485034This 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. (C) 2011 American Institute of Chemical Engineers Biotechnol. Prog., 27: 530-538, 2011Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); Federal Ministry of Education and Research (BMBF)Federal Ministry of Education & Research (BMBF) [108T293]; EBILTEM (Ege University, Research and Application Center of Science and Technology)Ege University; Ege University Research FoundationEge University [2009 Fen 0059]This work was supported by Scientific and Technological Research Council of Turkey (TUBITAK) and Federal Ministry of Education and Research (BMBF) under the Research Project number 108T293. EBILTEM (Ege University, Research and Application Center of Science and Technology) and Ege University Research Foundation (Project number 2009 Fen 0059) were also acknowledged for the research grants