Characterization and role of pendimethalin catabolizing bacteria isolated from agricultural soil in Bauchi, Bauchi state

The characterization and role of pendimethalin catabolizing bacteria isolated in three agricultural soils in Bauchi state. Analyses of physico-chemical parameters were carried out to further understand the soil environmental conditions of the sampling sites. Aerobic heterotrophic counts on the sampling sites for six (6) weeks were conducted and revealed increase of bacterial counts across the weeks; with the first week having low bacterial count of 104.333(×105 cfu/g) while week six (6) had the highest bacterial counts of 202.5(×105 cfu/g). Among the sampling sites: B1 and B2 had the lowest bacterial count compared to B3. This is as a result of the effects of herbicides accumulation in the soil. Bacterial abundance across the sampling sites showed high percentage of occurrence of Bacillus sp., Pseudomonas sp., Morganella sp.at (14.25%) each; when compared to Streptococcus sp. and Proteus sp.at (4.29%). The isolation of pendimethalin utilizing bacteria was conducted by enrichment cycle using mineral salt media containing pendimethalin (mg/ml) as a sole carbon source. Utilization patterns of pendimethalin degrading potentials of bacterial strains was determined via growth, utilization patterns and higher performance liquid chromatography analysis. Growth and utilization was monitored using spectrophotometer at 600 nm. Bacillus sp. and bacterial consortia showed high level of wavelengths at 0.424 and 0.481 respectively. High performance liquid chromatography analysis was conducted for 72 hours based on the peak reduction of standard pendimethalin and observed was a decrease in the area of the peak. Bacillus sp., Pseudomonas sp. revealed the highest rate of pendimethalin metabolism after 72 hours. Based on this research, indigenous microorganisms can be used for decontamination of agricultural soil. The Nigerian government and farmers at large should be careful on the type herbicides used for agricultural practices. For it affects soil microorganisms and crops.