International Journal of Waste Resources

Production and characterization of exopolysaccharide bioflocculants produced by Acromobacter spp.: Biosorption of heavy metals

2^nd World Congress and Expo on Recycling

July 25-27, 2016 Berlin, Germany

Banwari Lal and Sanjukta Subudhi

The Energy and Resources Institute, India

Posters & Accepted Abstracts: Int J Waste Resour

Abstract:

Present study highlights isolation of bio-flocculent producing microbes; Achromobacter sp. TERI-IASST N and Achromobacter xylosoxidans TERI L1, capable of biosorption of multi metals (Pb, Zn, Cd, Ni, and Cu). These microbes were isolated from heavy metal contaminated activated sludge samples collected from petroleum refineries. At optimum process parameters (pH 7.5, 37°C temperature, 1% sucrose as feed stock, 120 h incubation period) bioflocculating activity of â??TERI L1â?? strain enhanced (in presence of sucrose as carbon source) to 83.3%. This activity decreased to 73%, when grown in presence of multi-metals. â??TERI L1â?? could adsorb 90% of multi-metals when grown in presence of 1250 mg Lâ??1Zn, 2 mg Lâ??1Cd, 30 mg Lâ??1 Pb, 200 mg Lâ??1Ni and 90 mg Lâ??1Cu and could adsorb 1100 mg Lâ??1 of Pb, when grown in presence of 1500 ppm lead nitrate. â??TERI-IASST Nâ?? demonstrated 90% flocculation activity (in absence of heavy metals) at optimum condition; â??pH 6, temperature 37 oC, C/N ratio 1, 1% sucrose as feed stock, 120 h incubation period). In presence of multimetals, flocculation activity of strain N decreased to 84%. â??TERI-IASST Nâ?? strain revealed 430 mg Lâ??1 Zn and 30 mg Lâ??1 Pb. Bioflocculant yield efficiency of â??TERI-IASST Nâ?? and â??TERI L1â?? strains were; 10.5 g/L and 5 g/L, respectively. The bioflocculants were thermostable and retained up to 80% flocculating activity after being heated at 90ºC for 30 minutes, which is attributed to the polysaccharide backbone. LCâ??MS analysis confirmed the bioflocculants as, carbohydrate hetero-polymers. Nuclear magnetic resonance studies revealed that the bioflocculants were glycoproteins. To the best of our knowledge this is the first study that reports the isolation of A. xylosoxidans strain that has significant potential for bioflocculant production as well as for adsorption of multi-metals. The exopolysaccharide bioflocculants produced by â??TERI L1â?? and â??TERI-IASST Nâ?? strains have good potential for bioremediation of heavy metal contaminated wastewater.

Biography :

Email: banwaril@teri.res.in