Alcohol dehydrogenase (alcohol:NAD oxidoreductase, E.C. 184.108.40.206) activity was observed on acetaldehyde and n-hexanal in homogenized cell extract of Steptococcus lactis C2. Substrate inhibition was apparent at levels of n-hexanal above 4.0 mM. Increased centrifugal force from 12.000 × g for 20 min to 350,000 × g for 1 h resulted in increased specific activity in the cell-extract supernatant fluids. Aldehyde dehydrogenase (aldehyde: NAD oxidoreductose; E.C. 220.127.116.11) was not detected in any of the cell extracts. A possible involvement of the enzyme system with flavor modification in lactic-fermented oilseed milk is suggested.
1Florida Agricultural Experiment Stations Journal Series No. 1568.