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Characterization of a Bioflocculant (MBF-UFH) Produced by Bacillus sp. AEMREG7.

Okaiyeto K, Nwodo UU, Mabinya LV, Okoli AS, Okoh AI - Int J Mol Sci (2015)

Bottom Line: The production of the bioflocculant was observed to be closely associated with cell growth.The bioflocculant retained high flocculating activity of 90% after heating at 100 °C for 1 h.MBF-UFH appears to have immense potential as an alternative to conventional chemical flocculants.

View Article: PubMed Central - PubMed

Affiliation: South Africa-Medical Research Council (SA-MRC), Microbial Water Quality Monitoring Centre, University of Fort Hare, 5700 Alice, South Africa. okaiyetofranciskunle@yahoo.ca.

ABSTRACT
A bioflocculant named MBF-UFH produced by a Bacillus species isolated from sediment samples of Algoa Bay of the Eastern Cape Province of South Africa was characterized. The bacterial identification was through 16S rDNA sequencing; nucleotide sequences were deposited in GenBank as Bacillus sp. AEMREG7 with Accession Number KP659187. The production of the bioflocculant was observed to be closely associated with cell growth. The bioflocculant had the highest flocculating activity of 83.2% after 72 h of cultivation, and approximately 1.6 g of purified MBF-UFH was recovered from 1 L of fermentation broth. Its chemical analyses indicated that it is a glycoprotein composed of polysaccharide (76%) and protein (14%). Fourier transform infrared spectroscopy (FTIR) revealed that it consisted of hydroxyl, amide, carboxyl and methoxyl as the functional moieties. Scanning electron microscopy (SEM) revealed the amorphous structure of MBF-UFH and flocculated kaolin clay particles. The maximum flocculating activity of 92.6% against kaolin clay suspension was achieved at 0.3 mg/mL over pH ranges of 3-11 with the peak flocculating rate at pH 8 in the presence of MgCl2. The bioflocculant retained high flocculating activity of 90% after heating at 100 °C for 1 h. MBF-UFH appears to have immense potential as an alternative to conventional chemical flocculants.

No MeSH data available.


Effect of MBF-UFH concentration on the flocculating activity of purified bioflocculant produced by Bacillus sp. AEMREG7.
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ijms-16-12986-f004: Effect of MBF-UFH concentration on the flocculating activity of purified bioflocculant produced by Bacillus sp. AEMREG7.

Mentions: The effect of MBF-UFH dosage on flocculation efficiency for kaolin clay suspension was examined in an attempt to determine the most cost-effective dose for flocculation process. Under optimal conditions, the maximum flocculating activity is usually attained at the optimal bioflocculant dosage [36]. The flocculating activity of purified MBF-UFH was investigated in a range of 0.01–0.5 mg/mL (Figure 4). The flocculating activity of 61.5% was achieved at 0.01 mg/mL, and a further increase in MBF-UFH dosage resulted into a gradual decrease in flocculating activity. Nevertheless, the optimum bioflocculant dosage range for effective flocculation efficiency of over 90% was observed between 0.1 and 0.3 mg/mL, with the highest flocculating activity of 92.6% attained at 0.3 mg/mL. However, there was no significant increase in the flocculating activity of MBF-UFH when the dosage was increased from 0.1 up to 0.3 mg/mL (Figure 4). Although, the flocculating activity of MBF-UFH was low at 0.01 mg/mL (61.5%) compared to the flocculating activity noticed in the optimum range of 0.1–0.3 mg/mL (above 90%). At a lower dosage, MBF-UFH was relatively small to destabilize the negative charge of the kaolin clay particles, and the excess kaolin particles restabilized and increased the turbidity of the suspension; lower flocculating activity was noted in comparison to the flocculating rate observed at 0.1 mg/mL (Figure 4). This showed that the bridging effect of MBF-UFH was lower at 0.01 mg/mL compared to when it was at a higher dosage. On the contrary, the flocculating activity slightly decreased to 87.7% on increasing MBF-UFH dosage to 0.5 mg/mL compared with the flocculating activity of over 90% observed at an optimum dosage range between 0.1 and 0.3 mg/mL. This observation was in agreement with those reported elsewhere [37,38,39]. The decrease in flocculating activity of MBF-UFH observed at 0.5 mg/mL might be due to the over addition of the negatively-charged MBF-UFH, generating strong repulsive forces between the kaolin clay particles and the bioflocculant. These processes restabilized the suspended particles, increasing the viscosity of the suspension, blocking the adsorption sites and noticeably reduced floc formation [40]. These findings are consistence with previous studies reported by Elkady et al. [41] and Zheng et al. [9]. It has been extensively documented that a lower concentration of bioflocculants with a high flocculating efficiency will contribute to treatment cost reduction. Besides, information on the dosage requirement is substantial for future prospects in water treatment applications [28].


Characterization of a Bioflocculant (MBF-UFH) Produced by Bacillus sp. AEMREG7.

Okaiyeto K, Nwodo UU, Mabinya LV, Okoli AS, Okoh AI - Int J Mol Sci (2015)

Effect of MBF-UFH concentration on the flocculating activity of purified bioflocculant produced by Bacillus sp. AEMREG7.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490482&req=5

ijms-16-12986-f004: Effect of MBF-UFH concentration on the flocculating activity of purified bioflocculant produced by Bacillus sp. AEMREG7.
Mentions: The effect of MBF-UFH dosage on flocculation efficiency for kaolin clay suspension was examined in an attempt to determine the most cost-effective dose for flocculation process. Under optimal conditions, the maximum flocculating activity is usually attained at the optimal bioflocculant dosage [36]. The flocculating activity of purified MBF-UFH was investigated in a range of 0.01–0.5 mg/mL (Figure 4). The flocculating activity of 61.5% was achieved at 0.01 mg/mL, and a further increase in MBF-UFH dosage resulted into a gradual decrease in flocculating activity. Nevertheless, the optimum bioflocculant dosage range for effective flocculation efficiency of over 90% was observed between 0.1 and 0.3 mg/mL, with the highest flocculating activity of 92.6% attained at 0.3 mg/mL. However, there was no significant increase in the flocculating activity of MBF-UFH when the dosage was increased from 0.1 up to 0.3 mg/mL (Figure 4). Although, the flocculating activity of MBF-UFH was low at 0.01 mg/mL (61.5%) compared to the flocculating activity noticed in the optimum range of 0.1–0.3 mg/mL (above 90%). At a lower dosage, MBF-UFH was relatively small to destabilize the negative charge of the kaolin clay particles, and the excess kaolin particles restabilized and increased the turbidity of the suspension; lower flocculating activity was noted in comparison to the flocculating rate observed at 0.1 mg/mL (Figure 4). This showed that the bridging effect of MBF-UFH was lower at 0.01 mg/mL compared to when it was at a higher dosage. On the contrary, the flocculating activity slightly decreased to 87.7% on increasing MBF-UFH dosage to 0.5 mg/mL compared with the flocculating activity of over 90% observed at an optimum dosage range between 0.1 and 0.3 mg/mL. This observation was in agreement with those reported elsewhere [37,38,39]. The decrease in flocculating activity of MBF-UFH observed at 0.5 mg/mL might be due to the over addition of the negatively-charged MBF-UFH, generating strong repulsive forces between the kaolin clay particles and the bioflocculant. These processes restabilized the suspended particles, increasing the viscosity of the suspension, blocking the adsorption sites and noticeably reduced floc formation [40]. These findings are consistence with previous studies reported by Elkady et al. [41] and Zheng et al. [9]. It has been extensively documented that a lower concentration of bioflocculants with a high flocculating efficiency will contribute to treatment cost reduction. Besides, information on the dosage requirement is substantial for future prospects in water treatment applications [28].

Bottom Line: The production of the bioflocculant was observed to be closely associated with cell growth.The bioflocculant retained high flocculating activity of 90% after heating at 100 °C for 1 h.MBF-UFH appears to have immense potential as an alternative to conventional chemical flocculants.

View Article: PubMed Central - PubMed

Affiliation: South Africa-Medical Research Council (SA-MRC), Microbial Water Quality Monitoring Centre, University of Fort Hare, 5700 Alice, South Africa. okaiyetofranciskunle@yahoo.ca.

ABSTRACT
A bioflocculant named MBF-UFH produced by a Bacillus species isolated from sediment samples of Algoa Bay of the Eastern Cape Province of South Africa was characterized. The bacterial identification was through 16S rDNA sequencing; nucleotide sequences were deposited in GenBank as Bacillus sp. AEMREG7 with Accession Number KP659187. The production of the bioflocculant was observed to be closely associated with cell growth. The bioflocculant had the highest flocculating activity of 83.2% after 72 h of cultivation, and approximately 1.6 g of purified MBF-UFH was recovered from 1 L of fermentation broth. Its chemical analyses indicated that it is a glycoprotein composed of polysaccharide (76%) and protein (14%). Fourier transform infrared spectroscopy (FTIR) revealed that it consisted of hydroxyl, amide, carboxyl and methoxyl as the functional moieties. Scanning electron microscopy (SEM) revealed the amorphous structure of MBF-UFH and flocculated kaolin clay particles. The maximum flocculating activity of 92.6% against kaolin clay suspension was achieved at 0.3 mg/mL over pH ranges of 3-11 with the peak flocculating rate at pH 8 in the presence of MgCl2. The bioflocculant retained high flocculating activity of 90% after heating at 100 °C for 1 h. MBF-UFH appears to have immense potential as an alternative to conventional chemical flocculants.

No MeSH data available.