Characteristics of Gluconobacter oxydans B-1280 and Pichia methanolica MN4cell based biosensors for detection of ethanol

Pichia methanolica and Gluconobacter oxydans were immobilized on chromatogr aphic paper and fixed on an Clark type oxygen electrode. The lower limit of ethanol detection was 0.05 mM for both types of biosensors. Of all substra tes tested (ethanol, methanol, isopropanol, glucose, xylose, xylitol, arabi nose, arabitol, glycerol, pyruvate, citrate, acetate), the P. methanolica-b ased sensor had a higher selectivity and was susceptible only to ethanol, m ethanol and insignificantly to isopropanol. The sensor based on G. oxydans cells was less selective. The major interfering compounds were glucose and glycerol. The dependence of signal amplitude on the conditions of measureme nt and cell density was studied in both sensor models. The sensors proved r easonably stable and after 8 days of continuous measurements the signal dec reased not more than 50% for both types of biosensors. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.