title: Co-immobilization of glucoamylase and glucose oxidase for electrochemical sequential enzyme electrode for starch biosensor and biofuel cell.
abstract: A novel electrochemical sequential biosensor was constructed by co-immobilizing glucoamylase (GA) and glucose oxidase (GOD) on the multi-walled carbon nanotubes (MWNTs)-modified glassy carbon electrode (GCE) by chemical crosslinking method, where glutaraldehyde and bovine serum albumin was used as crosslinking and blocking agent, respectively. The proposed biosensor (GA/GOD/MWNTs/GCE) is capable of determining starch without using extra sensors such as Clark-type oxygen sensor or H2O2 sensor. The current linearly decreased with the increasing concentration of starch ranging from 0.005% to 0.7% (w/w) with the limit of detection of 0.003% (w/w) starch. The as-fabricated sequential biosensor can be applicable to the detection of the content of starch in real samples, which are in good accordance with traditional Fehling's titration. Finally, a stable starch/O2 biofuel cell was assembled using the GA/GOD/MWNTs/GCE as bioanode and laccase/MWNTs/GCE as biocathode, which exhibited open circuit voltage of ca. 0.53 V and the maximum power density of 8.15 μW cm(-2) at 0.31 V, comparable with the other glucose/O2 based biofuel cells reported recently. Therefore, the proposed biosensor exhibited attractive features such as good stability in weak acidic buffer, good operational stability, wide linear range and capable of determination of starch in real samples as well as optimal bioanode for the biofuel cell.
authors: Laboratory for Biosensing, Qingdao Institute of Bioenergy & Bioprocess Technology, Key Laboratory of Bioenergy, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101, China.
authors: Qiaolin
authors: Q
authors: Lang
authors: Long
authors: L
authors: Yin
authors: Jianguo
authors: J
authors: Shi
authors: Liang
authors: L
authors: Li
authors: Lin
authors: L
authors: Xia
authors: Aihua
authors: A
authors: Liu
mesh_terms: D000818:Animals; D001674:Bioelectric Energy Sources; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D005087:Glucan 1,4-alpha-Glucosidase / Q000737:chemistry* / Q000378:metabolism; D005949:Glucose Oxidase / Q000737:chemistry* / Q000378:metabolism; D057230:Limit of Detection; D013213:Starch / Q000032:analysis* / Q000378:metabolism
chemical_list: D004800:Enzymes, Immobilized; D013213:Starch; D005949:Glucose Oxidase; D005087:Glucan 1,4-alpha-Glucosidase
keywords: Biofuel cell; Glucoamylase; Glucose oxidase; Sequential enzyme biosensor; Starch biosensor