Degradation of carbofuran by Trametes versicolor in rice husk as a potential lignocellulosic substrate for biomixtures: From mineralization to toxicity reduction

Abstract

Biopurification systems for the treatment of pesticide-containing wastewaters contain a biomixture constituted by low-cost materials (soil, lignocellulosic substrates and humic components). In particular, the use of bioaugmented lignocellulosic materials as part of the biomixture components has been scarcely studied. The use of the fungus Trametes versicolor grown in rice husk (RH) was evaluated as an option of lignocellulosic bioaugmented substrate of potential application in biomixtures for carbofuran (CFN) elimination. RH supported growth and activity ofthe fungus, as evidenced visually and by laccase activity. The system was able to degrade 55.1% CFN in 34 d with a half-life of 29.9 d, and produced 3-hydroxycarbofuran (but not 3-ketocarbofuran) as a transformation product. This metabolite was successfully eliminated during the process. Moreover, a small fraction of CFN was mineralized (7.4%) within 64 d. Toxicological evaluation revealed a marked detoxification during the process, achieving an 89% decrease in the toxicity after 34 d. Overall performance of the bioaugmented substrate indicates that RH/T. versicolor is an interesting option to take into account in the design of biomixtures for pesticide degradation.