Monitoring the Bioutilization of Herbicide (Paraquat dichloride) by some Bacterial species Isolated from Soil in Calabar, Cross River State, Nigeria


T. O. Ozoude; C. A. Etok; E. U. Eleanya and O. K. Agwa (2018). Journal of Applied Life Sciences International 16 (1): 1-6

Herbicides though capable of killing weeds, also affect soil microorganisms depending on the dosage applied. They can also be used as sources of food for energy and growth by microorganisms. Some herbicides persist in the soil for a long period of time. These groups can be degraded by soil microorganisms. Thus this research was aimed at examining and isolating soil bacteria capable of utilizing the herbicide (paraquat dichloride), applied at different concentrations on the plot and also to assess its effects on the bacterial isolates. Using nutrient agar medium incorporated with nystatin to inhibit the growth of fungi, bacteria such as Bacillus sp., Micrococcus sp., Klebsiella sp., Pseudomonas sp., Listeria sp., Proteus sp., Streptococcus sp., and Staphylococcus sp were isolated. Screening test with mineral salt medium showed that all the isolates were able to utilize paraquat as substrate for growth and energy. The study also showed that Micrococcus sp., Bacillus and Proteus species especially were able to degrade the herbicide. Bacillus persisted till the eight weeks and was the most frequently isolated, followed by Micrococcus and Proteus sp. An increase was observed in microbial count within the first four weeks (5 *10 8 to 5.34 *108 and 5.3 *10 8 to 6. 64 *10 8 for plots 1 and 3 respectively) but by the sixth week the count decreased (4.70 * 108, 6.38 *108 for plots 1 and 3 respectively) as a result of substrate utilization simultaneously with degradation.

Prof. Comfort Etok

Professor Comfort Etok is a Professor of Microbiology from University of Uyo. Her area of specialization is Industrial/Food Biology. She has obtained her BSc, MSc. and Ph.D in Microbiology from University of Calabar..

She has been a recipient of several awards, one of which was the Professor Nduka Okafor’s prize for Best Graduating Student in Microbiology. She has served and is still serving in various committees in the University, State and National frontier. She has supervised and is still supervising intelligent undergraduate and postgraduate researches in Microbiology. One of such research worthy of note is “Fermentation And Amino Acid Profile Of Maize Pomace And Rice Husk And Their Dietary Effects On Broilers Chicken”.

She holds Membership in several Professional Bodies like American Society for Microbiolgy, Nigerian Society for Microbiology etc. She has published highly rated Journal Articles, Book Chapters etc. One of such publication shaking her field is “Bdellevibrio and Like Organisms: The much Anticipated “Magic Bullet”.” published by World News of National Science.
Visit her personal knowledgebase at to more about this great scholar.

More Products from Prof. Comfort Etok

Questions and Answers

You are not logged in

Have a Question? Submit it here!