Comparison of biodegradative efficiency of wildtype versus mutagenised Scenedesmus vacuolatus of spent coolant waste: dehydrogenase activity and total petroleum degradation studies

ABSTRACT

This study aims to compare the biodegradability efficiency of spent coolant waste by wild-type microalga versus mutagenised Scenedesmus vacuolatus. The biodegradation efficiency of both groups microalgae was evaluated using dehydrogenase activity (DHA) and total petroleum hydrocarbon (TPH) degradation using gas chromatography and mass spectrometry (GCMS). The DHA of both microalgae was conducted in relation to the triphenyl formazan production (TPF). The TPH of extracellular hydrocarbon degradation and intracellular hydrocarbons were analysed using GCMS. The data obtained from DHA and GCMS were analysed using analysis of variance at a 5% level of significance (0 < 0.05). The wild-type and mutagenised S. vacuolatus showed biodegradation of spent coolant waste after five weeks. The highest TPF produced by wild-type microalgae after five weeks was 1.139 mg/mL ± 0.009. The highest TPF produced by mutagenised S. vacuolatus after five weeks was 1.771 mg/mL ± 0.006 which was 1.55-fold higher than the TPF produced by the wild-type microalgae in the treatment weeks. The highest TPH degraded by wild-type after five weeks was 85.87% ± 0.20, while the highest TPH degradation of 100% was observed for the mutagenised S. vacuolatus after five weeks of spent coolant waste treatment. These results suggest that the mutagenised S. vacuolatus was better in utilising and degrading spent coolant waste and, therefore, can be used to mitigate spent oil pollution.

KEYWORDS:

• Spent coolant waste
• wild-type microalgae
• mutagenised scenedesmus vacuolatus
• biodegradation
• dehydrogenase activity
• gas chromatography and mass spectrometry

Acknowledgments

The authors acknowledge the National Research Foundation (NRF), South Africa and University of KwaZulu-Natal. The authors also thankfully acknowledge Carly Janse Van Rensburg from the Chemistry department, University of KwaZulu-Natal for providing all the necessary helps to carry out the gas chromatography and mass spectrometry experiment. Isaac Sanusi from the Microbiology department for all his help during the research work.

Availability of data and materials

All the data analyzed during this study are included in this research article and its supplementary documents.

Consent for publication

I Stella Eregie and Dr Sumaiyah Jamal-Ally, co-author of the manuscript provides consent for publication of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

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Additional information

Funding

This work was supported by the National Research Foundation (NRF), South Africa and University of KwaZulu-Natal