  Bentazone, an herbicide widely applied in rice and cereal crops, is
widespread in the aquatic environment. This study evaluated the capacity of
Trametes versicolor to remove bentazone from water. The fungus was able to
completely remove bentazone after three days at Erlenmeyer-scale incubation.
Both laccase and cytochrome P450 enzymatic systems were involved in bentazone
degradation. A total of 19 transformation products (TPs) were identified to be
formed during the process. The reactions involved in their formation included
hydroxylations, oxidations, methylations, N-nitrosation, and dimerization. A
laccase mediated radical mechanism was proposed for TP formation. In light of
the results obtained at the Erlenmeyer scale, a trickle-bed reactor with T.
versicolor immobilized on pine wood chips was set up to evaluate its stability
during bentazone removal under non-sterile conditions. After 30 days of
sequencing batch operation, an average bentazone removal of 48 % was obtained,
with a considerable contribution of adsorption onto the lignocellulosic support
material. Bacterial contamination, which is the bottleneck in the
implementation of fungal bioreactors, was successfully addressed by this
particular system according to its maintained performance. This research is a
pioneering step forward to the implementation of fungal bioremediation on a
real scale.
