The impact of concentration on the biotreatment of hair relaxers using Hydrocarbonoclastic Pseudomonas and Mucor Species from Ezu River, Awka, Nigeria
1 Department of Microbiology, Veritas University, Abuja, FCT, Nigeria.
2 Department of Applied Microbiology and Brewing Science, Nnamdi Azikiwe University, Awka, Nigeria.
Research Article
Open Access Research Journal of Science and Technology, 2023, 09(01), 021–029.
Article DOI: 10.53022/oarjst.2023.9.1.0056
Publication history:
Received on 29 July 2023; revised on 12 September 2023; accepted on 14 September 2023
Abstract:
The contamination of an aquatic environment by hydrocarbons and other noxious compounds due to human activities may cause toxicity to microorganisms and may stimulate microbial activity especially at low concentrations while their persistence can be detrimental to the entire ecosystem. It is crucial therefore, to assess the risks of these pollutants for environmental policy. Diesel was used as carbon source in mineral salts medium for the isolation of petroleum degrading microorganisms from Ezu River using vapor transfer technique. Plates were incubated at 37 0C and 28 0C for bacterial and fungal cultures, respectively. Of the 23 bacterial and 4 fungal isolates recovered, Mucor species and Pseudomonas aeruginosa were the best hydrocarbon utilizing isolates obtained. The isolates were assessed for their ability to utilize both lye-containing and lye-free hair relaxers at different concentrations (0.2 – 1% w/v) in mineral salts medium for 14 days. The optical density (OD660nm), the biochemical oxygen demand (BOD5), chemical oxygen demand (COD), and pH of the medium were monitored during incubation. The toxicity of the hair relaxers to Nitrobacter sp. was also assessed. Results showed that Pseudomonas aeruginosa utilized both lye-free(Lf) and lye-containing (Lc)hair relaxers at all concentrations as indicated by the high colony counts, reduction in BOD5 and COD during the incubation period. Mucor sp. grew better on higher concentrations Lc hair relaxer (1%> 0.8%> 0.6% w/v), but with minimal growth at lower concentrations of same relaxer (0.2%< 0.4%< 0.6% w/v). On the contrary, lye-free hair relaxer supported heavy growth of Mucor sp. at all concentrations tested. The growth of Nitrobacter sp. got inhibited by both types of hair relaxers between concentrations 0.6 and 1% w/v, with moderate growth at lower concentrations (0.2 – 0.4% w/v). The toxicity outcome of these hair relaxers to Nitrobacter species implies that the indiscriminate discharge of hair-relaxer-containing salon wastewater into the soil may affect the biogeochemical activities of the soil microbial communities. In addition, Pseudomonas aeruginosa and Mucor species recovered in this study can be used to attenuate sites contaminated by hair salon wastewater.
Keywords:
Biotreatment; Hydrocarbonoclastic; Hydrocarbon contamination; Attenuation
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