Enhancement of atrazine biodegradation by marine isolate Bacillus velezensis MHNK1 in presence of surfactin lipopeptide.

Atrazine is one of the widely used toxic herbicide and considered as serious environmental contaminant worldwide due to its long term use in crop production. In this study, the effect of surfactin lipopeptide produced by Bacillus velezensis MHNK1 on atrazine biodegradation was investigated. B. velezensis MHNK1 produced 0.83 ± 0.07 g/L of anionic biosurfactant that reduced surface tension from 72.12 ± 0.02 to 33.2 ± 0.61 mN/m and CMC was 40 mg/L with 85.21 ± 1.60% emulsification index. Further, biosurfactant was characterized as surfactin by TLC, HPLC, FTIR, 1H and 13C NMR and LCMS-ESI. B. velezensis MHNK1 showed 87.10 ± 3.10% atrazine biodegradation within 5 days which was revealed by HPLC and MS analysis. Atrazine biodegradation using a combination of B. velezensis MHNK1 (2%) and surfactin (2 CMC) resulted in 100 ± 1.20% degradation within 4 days. Presence of atrazine degrading genes in B. velezensis MHNK1 was also confirmed by PCR. To the best of our knowledge, there are no previous reports available on atrazine degradation using B. velezensis strain and also in combination with surfactin. The results of this study reveal that strain B. velezensis MHNK1 and surfactin can be potential source of ecofriendly application for removal of atrazine from contaminated sites.