Microbial Consortium of Saccharomyces cerevisiae and Bacillus megaterium as Alcohol Dehydrogenase (ADH) Production for Ethanol Biosensor

Determining ethanol levels is very important in the food and beverage industry, especially in relation to health and permissible limits. Biosensors are one alternative for measuring ethanol levels because they are inexpensive, easy to use, fast, and sensitive in measurement. Previous research results from researchers have shown that ethanol biosensors using microbial consortia as a substitute for enzymes can detect ethanol in the range of 0.2-6% with 80% stability during 7 weeks of storage. However, the ethanol detection range is still not wide enough, so further research is needed to expand the ethanol detection range. The objective of this study is to produce an ethanol biosensor based on a microbial consortium with a wider detection range, high linearity, and stability equivalent to ADH as an enzyme for detecting ethanol. The methods used to achieve this objective were to optimize the formation of a biofilm consortium of S. cerevisiae and B. megaterium as ADH producers, compare the quality of ethanol biosensors using microbial consortia with pure ADH, and determine analytical performance. Pure ADH at a concentration of 3 µg/mL was tested on 10% ethanol, producing an oxidation current of 45 µA. Ethanol concentrations of 0.1-10% tested using the ethanol biosensor produced an optimal oxidation current of approximately 60 µA, which was linear with increasing ethanol concentration and had a storage stability of 80% over 10 weeks of storage.