Potential of Pycnoporus sanguineus (NUOL-PPK.02) for Bioremediation of Chlorpyrifos and Azoxystrobin in an Autoclaved Soil-Based Biomixture: A Pot Incubation Study

Chlorpyrifos and azoxystrobin are among the most heavily used pesticides in banana production in many parts of the world, including the Lao People’s Democratic Republic (Lao PDR) and Thailand. In these systems, soils may receive an organophosphate insecticide and a strobilurin fungicide together, often alongside copper-based products. This study evaluated the bioremediation potential of Pycnoporus sanguineus (NUOL-PPK.02), a white-rot fungus isolated from decaying wood in Lao PDR. A pot incubation experiment was carried out under controlled conditions in an autoclaved soil-based biomixture (soil, sawdust, rice bran and calcium carbonate) using a completely randomised design with three replicates. Treatments comprised an uncontaminated biomixture control, an uncontaminated biomixture inoculated with P. sanguineus, and three application rates of each pesticide with and without fungal inoculation, with the non-inoculated pesticide treatments serving as controls for abiotic dissipation. Chlorpyrifos was applied at 16.3, 24.5 and 32.7 mg a.i. kg−1 dry biomixture and azoxystrobin at 10.2, 15.3 and 20.4 mg a.i. kg−1; measured initial concentrations 24 h after application were 8.39–10.58 and 4.73–5.54 mg kg−1, respectively. Residues were quantified by liquid chromatography–tandem mass spectrometry. After 60 days of incubation, the inoculated biomixture had lost 32%, 23% and 22% of chlorpyrifos and 76%, 60% and 53% of azoxystrobin, compared with 28%, 20% and 18% and 27%, 28% and 36% in the corresponding non-inoculated controls; differences were significant for azoxystrobin (Tukey’s HSD, p ≤ 0.05) but not consistently so for chlorpyrifos. The fungus tolerated both pesticides, although mycelial growth was inhibited by up to 51% (chlorpyrifos) and 60% (azoxystrobin), while available phosphorus, cation exchange capacity and organic matter content increased in the inoculated biomixture. These results indicate that P. sanguineus (NUOL-PPK.02) can accelerate the degradation of azoxystrobin under the conditions tested, while contributing little to the dissipation of chlorpyrifos, and that fungal inoculation concurrently improves biomixture chemical properties.