The average concentrations of lactic acid, ethanol and acetate in
phase 2 were 191.3, 37.0 and 42.3 mM, while in phase 3 were
114.8, 86.9 and 43.7 mM. The ratio of lactic acid to the sum of etha-nol and acetate in phase 2 was 2.4 while in phase 3 was 0.9.
Therefore, the fermentation type in phase 2 may be the coexistence
of heterofermentation and homofermentation, however, heterofer-mentation was very likely to be the dominant fermentation route
in phase 3. In addition, the ratio of acetate to ethanol was 0.5,
meaning that the heterofermentation was mainly by fermentation
with equimolar amounts of CO2
, lactate and ethanol.