The changes in chlorothalonil concentration during fermentation
were also studied (Fig. 3D). When pretreated by Chd, the
chlorothalonil concentration decreased before fermentation. The
chlorothalonil continued to be degraded during alcoholic fermentation
even at a lower temperature. When the treatment time was
60 min, 95.36% of chlorothalonil was degraded before fermentation
and 98.29% after fermentation, with only 0.0017 g L1 chlorothalonil
existed in the broth finally. When the treatment time was
30 min, the chlorothalonil residue in the slurry was reduced by
65.6% and 80.94% before and after fermentation, respectively. After
Chd treatment, the chlorothalonil concentration in broth was still
higher than 0.03 g L1
, and the residual chlorothalonil concentration
was also higher than 0.02 g L1 until the end of fermentation.
Therefore, the inhibition still existed. The result was consistent
with the data presented in Fig. 2 and 3. If the residual chlorothalonil
concentration was lower than 0.02 g L1 in broth after
chlorothalonil-degrading enzyme treatment, the yeast cells did not
need consume a lot of sugar to maintain their growth, more sugar
could be used for alcohol production. Meanwhile the S. cerevisiae
viability could be maintained to improve the fermentation effi-
ciency (Fig. 4). Furthermore, as shown in Fig. 2D, the chlorothalonil
concentration would not be changed if no Chd was added, con-
firming that it was Chd who eliminated or alleviated the adverse
effect of chlorothalonil during the winemaking process