Heavy metals biosorption by urease producing Lysinibacillus fusiformis 5B

摘要

Biosorption is the ability of biological materials to accumulate heavy metals from wastewater through mediated or physico-chemical pathways of uptake. Urease producing bacteria have been hypothesized to have inherent bioremediation abilities. The aim of this research was to determine the potential of Lysinibacillus fusiformis 5B to biosorp Pb, Cr, Cd and Ni. The stock solution of Pb, Cr, Cd and Ni was prepared by dissolving 0.0157 g of Pb(C2H3O2)2, 0.057 g of K2Cr2O7, 0.018 g of CdSO4 and 0.026 g of NiSO4 in 100 mL of dH2O respectively. Lysinibacillus fusiformis 5B was screened for the potential to utilise 5 ppm of the heavy metals using agar dilution method. Broth of L. fusiformis 5B was inoculated to 10, 15, 20 and 50 ppm of the heavy metals. The rate of biosorption was determined by atomic absorption spectroscopy (AAS) after 0, 7, 14, 21, 28 and 35 days. The biosorption % was determined by Beer Lambart’s equation. Lysinibacillus fusiformis 5B was able to tolerate 5 ppm concentration of all the heavy metals by showing visible growth on surfaces of nutrient agar Petri plates. Generally, there was an increase in biosorption rate as the days progress. After 35 days of incubation, the highest biosorption rate of 99.96%, 99.97%, and 99.94% were recorded for Pb, Cr, and Cd respectively at 10 ppm and 99.33% of Ni at 15 ppm. The results of this study showed that L. fusiformis 5B possess the capacity to biosorp Pb, Cr, Cd and Ni and can be developed as biosorption agent for these heavy metals.