On-line control of glucose concentration using an automatic glucose analyzer

Abstract

The fundamental characteristics of an automatic glucose analyzer which consists of sampling, sensor, and operation units were examined. The glucose sensor is a dual cathode type which has an immobilized glucose oxidase membrane coupled with an oxygen sensor. Using this glucose sensor combined with an automatic sampling device, on-off control of the glucose concentration in fed-batch cultures of Saccharomyces cerevisiae was carried out. When the glucose concentration to be controlled was set at 0.3 and 10 g/ l, the concentration was well maintained within the range of 0.08−0.54 g/ l in the former, and within 9.2–11.1 g/ l in the latter. In the former experiment, 1.67 g/ l of ethanol was produced at the end of cultivation (OD 570=34). On the other hand, 12.9 g/ l of ethanol was accumulated at the end of cultivation (OD 570=43) in the latter experiment. Fed-batch cultures of Micrococcus ruteus were also carried out. The glucose concentration was set at 2.5 g/ l. The microorganism grew up to OD 610=264 and the glucose concentration was maintained within 2.0 and 3.1 g/ l.