Production and characteristics of a heavy metals removing bioflocculant produced by Pseudomonas aeruginosa
eman gomaa Pol J Microbiol 2012; 61 (4): ICID: 1031326 Article type: Original article IC™ Value: 10.00
Abstract provided by Publisher
The flocculating activity of a bioflocculant produced by Pseudomonas aeruginosa ATCC-10145 using the kaolin clay was assayed. Influence of carbon, nitrogen sources, pH and culture temperature on bioflocculant production were investigated. Effects of cationic compounds, bioﬂocculant dosage, pH and temperature on the flocculating activity were also determined. Of the cations tested, Ca2+, K +, Na+, Zn2+, Mg2+ and Cu2+ improved flocculating activity whereas Fe3+ and Al3+ caused inhibition of flocculating activity. The highest flocculating activity was observed at pH 7.0.The bioflocculant had a good flocculating activity of 80.50% for kaolin suspension with a dosage of only 1%. The bioflocculant was heat-stable and its activity was only decreased to 60.16% after heating at 100 oC for 60 min. Chemical analyses of the puriﬁed bioﬂocculant indicated that it was a sugar-protein derivative, composed of protein (27%, w/w) and carbohydrate (89%,w/w ) including neutral sugar, uronic acid and amino sugar as the principal constituents in the relative weight proportions of 30.6%, 2.35% and 0.78%, respectively. The elemental analysis of the bioﬂocculant revealed the mass proportion of C, H and N was19.06, 3.88 and 4.32 (%), correspondently. Fourier transform infrared analysis showed that the exopolymers consisted of carboxyl, hydroxyl, amino and sugar derivative groups. The heavy metal adsorption by the bioflocculant of Pseudomonas aeruginosa was found to be influenced by the initial metal concentration, bioﬂocculant concentration and pH of the biosorption solution. This study demonstrates that microbial bioflocculant has potential to be used as an alternative bioremedial tool for industrial effluents and wastewater treatments which are co-contaminated with heavy metals.