MOLECULAR CHARACTERIZATION OF INDIGENOUS ATRAZINE DEGRADERS FROM AGRICULTURAL FIELDS IN LAGOS, SOUTHWEST NIGERIA

Abstract

Two composite soil samples were obtained from Lagos state agricultural field at Ikorodu and Lagos State University (LASU) agricultural field, both fields having over 10 years history of Atrazine application. The soil samples were obtained from 0 - 30cm depth with sterile soil auger. The control soil samples with no previous history of Atrazine application were obtained from Badagry beach at the same depth. Physico-chemical analysis of both composite soil samples (mean pH 4.93) and composite water samples obtained from nearby freshwater stream (mean pH 4.55) at the same depth were determined. Analysis of variance (ANOVA) showed there was significant relationship among the parameter and across the locations the result was not significantly different at 0.05 level of significance. Serial dilution technique was engaged to obtain indigenous microbial population while bacterial atrazine - degraders were obtained using minimal salt medium supplemented with 3% atrazine and fungal species with Sabouraud Dextrose agar (SDA) supplemented with atrazine at 5% respectively. Biodegradation / Time-Course study revealed Atrazine concentration reduction using Spectrophotometric analysis. DNA of some selected isolates were extracted and sequenced using 16S rRNA and ITS methods. The genetic data of these isolates were submitted to the NCBI GeneBank database. The selected Atrazine degraders identities were confirmed as follows; Pseudomonas alcaligenes (MT355448.1), Bacillus mycoides (JX144699.1) and Aspergillus aculeatus (LC496490.1) in the NCBI database.