Isolation of Metribuzin Degrading Soil Bacteria and Assessment of Their Growth in Response to Selected Physical Chemical Conditions

Abstract

Soil from designated farms with history of metribuzin use was screened for metribuzin degrading bacteria. Mineral salts media, incorporated with metribuzin as the sole carbon source was used to isolate the bacteria. Seven bacteria species were isolated and coded as follows; NZ453A, NZ454B, NZ453C, NZ543A, NZ543B, NZ8070 and NZ1110. Molecular characterization using 16sRNA was carried out to identify the isolated bacteria. They were identified to belong to groups of; Pseudomonas sp., Burkholderia sp., Staphylococcus sp., Bacillus sp Arthrobacter sp., Bacillus sp.,and Planomicrobium sp.,The effect of pH, temperature, nitrogen and phosphorous concentrations on growth of the isolated bacteria was assessed by optical density measurements in growth media. Generally, the bacteria recorded highest growth in alkali pH and temperature of 35^o C. Increased concentration of nitrogen and phosphorous showed a general increase in bacterial growth. Results showed a significant difference (p < 0.5) in growth among the isolated bacteria in the treatments used. The study revealed some of the physico-chemical treatments that can be used invitro for multiplication of metribuzin degrading bacteria for further development as bio degraders of metribuzin in contaminated sites. The information can also be used to create a favourable niche insitu, to enhance bacteria multiplication during bioremediation of metribuzin contaminated sites.

Keywords: Bacteria, Degrading, Metribuzin, Physico-chemical treatments