| dc.description.abstract | Antioxidant biosensor based on pure superoxide dismutase (SOD) has drawbacks, such as high price and low stability. The solution of those shortcomings was using of bacteria that produced SOD as a sensor. Escherichia coli has been known to produce SOD, type Cu/Zn-SOD and Mn-SOD. The optimum conditions SOD antioxidant activity obtained by Response Optimizer in Minitab were 37 °C, pH 7, and 30 mg zeolites for E. coli extract and 40 °C, pH 7, and 240 mg zeolites for E. coli cells. KM app and Imax app values of SOD from E. coli extract were determined by Lineweaver-Burk method. The KM app and Imax app values were 1.1376 mM and 2.3770 μA (immobilized on zeolites) and 2.4039 mM and 2.5012 μA (without immobilization), respectively. The electrodes of zeolites as immobilization matrix was relatively stable until 4 hours, the remaining antioxidant activity was 88.91%, whereas the stability of electrodes without zeolites gradually fall, the remaining antioxidant activity until 12 hours was 11.67%. | en |
