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Abstract
This study aims to evaluate and optimize the flocculating activity of crude bio-flocculants from selected bacteria isolates in river Oyun, Ilorin Kwara state. Water samples were collected for bacteria isolation. Screening of the isolate for duplicate and bio-flocculant production before optimization of conditions and molecular identification was done. Seventeen (17) bacteria isolates were obtained after preliminary screening to remove duplicate organisms. Out of these, six (6) with bio-flocculant capability were selected for optimization via variation with respective pH range, carbon and cation sources. The isolates were identified via molecular analysis as Comamonas aquatica MTK09, Pseudomonas aeruginosa MTK10, Aeromonas sp. MTK11, Aeromonas caviae MTK12, Pseudomonas sp. MTK13 and Aeromonas veronii MTK14 respectively after sequence blast. Highest activity (82.6%) across all sources were recorded with Aeromonas caviae MTK12, followed by Aeromonas sp. MTK11 and Pseudomonas sp. MTK13 using lactose as the sole carbon source. However, starch yielded least flocculating rate with all the bacteria isolates. Although, use of divalent cation source (FeSO4) recorded highest overall flocculating activity (298.6%) while highest activity yields of 74.2% was obtained with KCl for Pseudomonas aeruginosa MTK10. The bio-flocculant activities of the isolates were most active at pH 12 with overall activity of 488.9% and optimized result of 99.5% for Aeromonas caviae MTK12 while other pH ranges also had significant activities for other isolates. In conclusion, this study reveals that the activity of bio-flocculants can be improved via change of production conditions thereby obtaining better yield which in turn can improve the flocculating activity. Furthermore, the respective activities of the isolates recorded at varying pH acclaim its applicability in different environmental conditions.
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Keywords: Bio-flocculants, Oyun river, Cations, Carbon, Flocculating activity, Optimization
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