Filamentous fungi with high paraquat‐degrading activity isolated from contaminated agricultural soils in northern Thailand

Abstract

The contamination of paraquat (1,1′‐dimethyl‐4,4′‐bipyridylium dichloride) herbicide from the farming area has become a public concern in many countries. This herbicide harms to human health and negatively effects the soil fertility. Several methods have been introduced for the remediation of paraquat. In this study, 20 isolates of the paraquat‐tolerant fungi were isolated from the contaminated soil samples in northern Thailand. We found that isolate PRPY‐2 and PFCM‐1 exhibited the highest degradation activity of paraquat on synthetic liquid medium. About 80 and 68% of paraquat were removed by PRPY‐2 and PFCM‐1 respectively after 15 days of cultivation. Based on the morphological characteristic and molecular analysis, the fungal isolate PRPY‐2 and PFCM‐1 were identified as Aspergillus tamarii and Cunninghamella sp. respectively. The biosorption of paraquat on these fungal mycelia was also investigated. It was found that only 8–10% of paraquat could be detected on their mycelia, while 24–46% of paraquat was degraded by fungal mycelia. This is the first report on paraquat degrading ability by A. tamarii and Cunninghamella sp. It is demonstrated that these filamentous fungi are promising microorganisms available for remediation of paraquat contaminated environment.

Multifarious Characterization and Efficacy of Three Phosphate-Solubilizing Aspergillus Species as Biostimulants in Improving Root Induction of Cassava and Sugarcane Stem Cuttings

“…It was found that A. pseudopiperis and A. pseudotubingensis could tolerate methomyl and propargite, respec-tively, in the field at recommended dosages. These findings are consistent with previous studies that demonstrated that some PSF species of the genera Aspergillus, Chaetomium, Clonostachys, Grifola, Minimedusa, Mucor, Penicillium, Phycomyces, Pochonia, Purpureocillium, Rhizopus, and Trichoderma could tolerate agrochemicals at various dosages depending on the species and strain [101][102][103][104][105][106]. Notably, Benito et al [107] found that A. flavus AFS 63 and A. parasiticus APS 55 were able to tolerate glyphosate (herbicide) at the recommended field dosages.…”

Achromobacter sp. Strain BUKˍBCHˍTQ1: A Potential Paraquat-Degrading Bacterium Isolated from Pesticide Contaminated Agricultural Soil

“…The data obtained indicates that concentration above 276 mg/L was toxic to these bacterial strains, leading to proportional decrease in biodegradation efficiency of paraquat. Research by Wongputtisin et al, (28), reported the optimum substrate to be 0.5g/L with a similar findings reported also by (27,29). This observation reinforces the notion that elevated paraquat concentrations could exert a toxic effect on metabolic activities, thereby potentially compromising the efficiency of bacterial degradation.…”