Bioremediation of 2,4-Diaminotoluene in Aqueous Solution Enhanced by Lipopeptide Biosurfactant Production from Bacterial Strains

Abstract

This research concentrated on the isolation and preparation of biosurfactant-producing bacterial strains for the degradation of aromatic amine compound 2,4-diaminotoluene (2,4-DAT). Three strains, designated as Isolates 1, 2, and 3 (I1, I2, and I3), were isolated from soil and used in the degradation studies. Among the three isolates, I1 showed the highest growth rate and degradation capacity, approximately 30 mg L−1. The highest degrading capability was found in I1 followed by I2 and I3. The three strains were tested for biosurfactant screening, and the lipopeptide nature of the biosurfactant was identified through characterization studies. The stability of the biosurfactants was also tested at different temperatures and in various pH ranges. The investigation of biosurfactant-mediated remediation was further carried out using the three strains and lipopeptide biosurfactants. Intermediates formed after degradation were analyzed using high-performance liquid chromatography (HPLC), which showed that the compounds were eluted within 3 min. The results showed that biosurfactants raised the degrading capability of these strains for 2,4-DAT by 14.54, 27.15, and 35.79 mg L−1.