4. Conclusions
A microbial biosensor for ethanol based on yeast cell of S.
ellipsoideus and potentiometric oxygen electrode was produced
and characterised. The main advantage of this biosensor
is its construction simplicity and low cost.
Optimum working conditions were pH 7 and temperature
of 25 ◦C. A fast response of about 2 min was registered for
yeast immobilised on a DM and about 7 min for selective
biosensor with yeast immobilised on a PTFE membrane.
The interference of glucose in ethanol determination is
significant even after yeast incubation with ethanol before
biosensor preparation. Use of the PTFE membrane allows
one to prepare a highly selective biosensor for ethanol.
A linear calibration plot was recorded for more than three
decades of ethanol concentration, being the most extended
calibration plot of all microbial biosensor calibrations previously
reported [34,35]. A comparable detection limit was
obtained with that of a similar amperometric biosensor described
elsewhere [23].
Comparable sensitivity and good correlation with the enzymatic
spectrophotometric method were observed.