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摘要
The detrimental effects of inorganic and organic synthetic flocculants on humans and their recalcitrance in the environment have necessitated the search for safe, eco-friendly alternatives, including microbial flocculants. A bioflocculant-producing bacteria was isolated from sediment samples of Algoa Bay in the Eastern Cape Province of South Africa. The bacteria was identified through partial 16S ribosomal ribonucleic acids (rRNA), nucleotide sequencing, and BLAST analysis of the gene sequence that showed the bacteria to have 98% similarity to Bacillus algicola strain QD43 and deposited in GenBank as Bacillus sp. AEMREG7 with accession number KF933697.1. The effect of culture conditions on MBF-UFH production revealed optimally at inoculum size of 3% (v/v), glucose, a mixed nitrogen source [NH4 (SO4)(2) + urea + yeast extract], and pH 6 for inoculums size, carbon and nitrogen sources, and initial medium pH for the fermentation process, respectively. The spent culture broth-rich bioflocculant attained the highest flocculating activity of 88.5% after 72 h of fermentation during the exponential phase of bacterial growth. It showed a high flocculating activity for kaolin clay suspension over a wide pH range of 4-10 with maximum flocculating activity observed at pH 6; and also retained 70.5% flocculating activity after heating at 100 degrees C for 60 min. These findings suggest that MBF-UFH has a great potential to substitute hazardous chemical flocculants commonly used in water treatment, hence reducing deformities among individuals in society.
- 出版日期2016
