Bioprospecting Microbial Consortia for Tebuthiuron Degradation in Agricultural Soils: An Alternative Bayesian-Driven Colorimetric Protocol

Abstract

Herbicides impact, particularly tebuthiuron (TBT), on agroecosystems and surrounding environments had been documented in scientific literature. This study investigated the hypothesis that areas exposed to TBT, a prevalent herbicide in Brazil's sugarcane crops, might harbour microbial consortia capable of degrading this compound, assessed through a Bayesian-based colorimetric method. Soil samples from plant cane (pC), characterised by lower organic matter on the surface, and first-cut ratoon cane (rC) fields, with higher organic matter due to crop residues deposition, were collected for analysis. Colorimetric assays with DCPIP (2,6-Dichlorophenolindophenol) were performed with microorganisms isolated from these fields to evaluate their TBT-degradation capacity. In an ELISA microplate, absorbance was measured at 600 nm as DCPIP is a redox indicator. Results confirmed the degradation potential of soil microbial consortia, particularly from rC samples, as evidenced by reduced absorbance relative to the control. The data deviated from the expected sigmoidal pattern, necessitating an alternative data interpretation method. A Bayesian factor estimation approach for kernel density curves of the logarithmic response ratio proved effective for handling non-sigmoidal spectrophotometric data. The findings offered valuable insights into TBT-degrading microorganisms and introduced an alternative analytical tool for interpreting variable data, potentially aiding in the development of bio-based remediation strategies.