Browsing by Author "Schmidt, Stefan"

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    Potential Impact of Cypermethrin on Selected Groups of Soil Microorganisms
    (Egyptian Academic Journal of Biological Sciences, 2017-06-01) Anozie, Patience C.; Ilori, Matthew O.; Amund, Olukayode O.; Schmidt, Stefan
    Application of cypermethrin as insecticide during agricultural practices is a global concern due to its toxicity and potential accumulation of its metabolites in the aquatic environment. A mesocosm plot of agricultural land (500 m2) was demarcated and deliberately contaminated with cypermethrin to study its impact on the autochthonous microorganisms. Potential effects of 3- phenoxybenzoic acid (3-PBA), a known suicide metabolite of cypermethrin, on hydrolytic activities were also investigated by using fluorescein diacetate assay (FDA). A significant increase in the abundance of total heterotrophic bacteria from 3.55 x 106cfu g-1to 1.30 x 108cfu g-1in 12 weeks as against the control was induced by the insecticide in the mesocosm. The number of starch hydrolysing bacteria increased after the second insecticide treatment from 6.25 x 106cfu g-1to 2.70 x 107 cfu g-1in three weeks. However, there was no significant increase in the microbial count of fungi, presumptive actinomycetes and nitrogen fixing bacteria during the twelve weeks of experiment. The hydrolytic activity of soil microorganisms was apparently inhibited insoil treated with different concentration of 3-PBAthan in untreated soil. These results suggest that the application of a commercial cypermethrin formulation increased the abundance of selected soil microorganisms while3- PBA reduced the soil microbial hydrolytic activity.
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    Utilization of Tannic Acid by Bacteria in Tropical Aquatic and Soil Environments
    (JMBFS, 2020-12-01) Olumuyiwa, Emmanuel; Amund, Olukayode O.; Ilori, Matthew; Schmidt, Stefan
    Two bacterial strains designated as EO1 and EO2, were isolated by selective culture enrichment from Lagos lagoon water and mangrove soil samples. They were subsequently identified based on morphological and physiological characteristics as well as 16S rRNA gene sequence analysis as Klebsiella pneumoniae strain EO1 and Pantoea cypripedii strain EO2 with accession numbers KX355800 and KX355801. Microbial growth assessment was performed in triplicates under aerobic batch conditions. The two isolates were capable of utilizing tannic acid, gallic acid, glucose, succinate, benzoic acid, and protocatechuic acid as sole carbon sources. Growth experiments along with enzymatic studies indicated that the organisms hydrolyzed tannic acid through gallic acid and pyrogallol as metabolic intermediates. The organisms have potential for the elimination of polyphenolic pollutants such as gallotannins associated with wood residues in Nigerian estuarine environments.