Isolation and characterization of a thermophilic Streptromyces albidoflavus strain KS5 capable of glyphosate degradation

Abstract

A thermophilic actinobacterium was isolated from thermal waters in Khenchela, Algeria, and identified as <i>Streptomyces albidoflavus</i> (accession number: OQ727247) based on biochemical characterization and 16S rRNA gene sequencing. Designated as strain KS5, this bacterium demonstrated the capacity to degrade 50 mg L^-1 of glyphosate within 15 days at both 30 °C and 50 °C. Remarkably, strain KS5 utilized glyphosate as its sole carbon source under these temperature conditions. Biodegradation efficiency was optimized through colorimetric assays evaluating key parameters such as pH, temperature, and inoculum size. The maximum degradation occurred at 50 °C, with optimal conditions determined at pH 7.2 and an inoculum size of 70 mg L^-1. Total organic carbon reduction reached 53.68% at 50 °C compared to 47.27% at 30 °C. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy further confirmed structural modifications in glyphosate following incubation with strain KS5. Collectively, these results underscore the potential of this thermophilic <i>Streptomyces</i> strain for glyphosate biodegradation under both mesophilic and thermophilic conditions, highlighting its promise for bioremediation of environments contaminated by this herbicide.