**4. Conclusion**

In the control reaction of *A. sydowii* CBMAI 935 and *P. raistrickii* CBMAI 931, in the absence of the pesticide, there was a much greater mycelia growth indicating that the pesticide can partially inhibit the growth of fungi, as noted previously in the screenings carried out on solid

Br

Br

Cl

Cl

Figure 12. Degradation of profenofos in aqueous medium

*3.4.4. Biodegradation of the pesticide profenofos by P. raistrickii CBMAI 931 at several concentrations*

Aiming to evaluate the biodegradation of the pesticide profenofos at various concentrations, this test was carried out with variations of the initial concentration under standard biodegra‐ dation reaction (liquid culture medium with malt + profenofos + fungal inoculum for 30 days). The reactions were performed in duplicate, at concentrations of 15.0, 30.0, 50.0 and 65.0 ppm, and also a pesticide control (liquid culture medium + profenofos) was carried out and average

**cinitial a profenofos cfinal a profenofos\* ca metaboliteb %of profenofos degraded** 15.0 0.5 4,90 98 30.0 0.6 20,40 98 50.0 2.5 24,1 95 65.0 3.2 27,9 95 30.0 (control) 14.9 10,8 50

**Table 10.** Quantitative biodegradation of profenofos by *P. raistrickii* CBMAI 931 in different concentrations, at 30 days

O P SH OH O

OH

+

+ C2H5OH + C3H7SH

O P <sup>S</sup> <sup>O</sup> -O

medium (Table 9).

Cl

Br

a

b4-bromo-2-chlorophenol

in liquid medium (32 °C, 130 rpm, pH 7).

O P <sup>S</sup> <sup>O</sup> <sup>O</sup>

172 Applied Bioremediation - Active and Passive Approaches

results are shown in Table 10.

profenofos H2O, HO-

**Figure 12.** Degradation of profenofos in aqueous medium

c (ppm) = concentration (data in duplicates) determined by GC-MS-SIM

H2O, H<sup>+</sup>

The growth of fungal strains on profenofos was promising, even at the highest tested concen‐ tration. The fungi *P. raistrickii* CBMAI 931, *A. sydowii* CBMAI 935, *A. sydowii* CBMAI 1241 and *Trichoderma* sp. CBMAI 932 may have a good biocatalytic potential in the presence of profe‐ nofos, according to the results of screening. Marine fungi should be further explored as sources of enzymes capable of degrading OPs, since studies in fungal bioremediation of pesticides has shown great potential, albeit much less explored than bacterial bioremediation.

The fungi *P. raistrickii* CBMAI 931 and *A. sydowii* CBMAI 935 were efficient in profenofos biodegrading in liquid medium, as well as promoting the transformation or degradation of the metabolite, 4-bromo-2-chlorophenol, and showing that the enzymatic system of these fungi effectively expressed the necessary enzymes for a complete degradation process. Further research is under way to assess the biodegradation of methyl parathion and chlorpyrifos.

Liquid medium reactions using *P. raistrickii* CBMAI 931 with increasing concentration of the pesticide leaded to the almost complete biodegradation (99.0 to 95.0%) of the pesticide profenofos at all concentrations (15.0, 30.0, 50.0 and 65.0 ppm), showing that this fungus is resistant to high concentrations of this pesticide. The fungus *P. raistrickii*-CBMAI 931 may be a good source of phosphotriesterases, which could be isolated and purified for applications in biotechnology, biodegradation reactions in soil and water contaminated with pesticides.
