Removal of Lead Contamination through the Formation of Lead-Nanoplates by a Hot Spring Microbial Protein

Lead contamination still remains as serious threat to public health and environment because of its non-biodegradability and toxicity. A clean technique has been developed for removal of lead contamination through the formation of lead-oxide nanoplates using a bacterial protein (Molecular weight ~30 kDa) as biological template. The isolated hot-spring bacterial (the bacterium was named as MDH1) protein when adding to the solution of lead compound (e.g., lead nitrate), nanoplates of lead-oxide are formed as viewed by electron microscope. The as prepared lead-oxide-nanoplates are characterized by Inductively Coupled Plasma analysis, Energy Dispersive X-ray Spectroscopy and X-ray diffraction analyses. The lead-oxide-nanoplates and the filtered supernatant of the reactive solution both were separately used to observe the inhibition of growth of E. coli bacteria on culture plate. Lead-oxide-nanoplates produced clear zone of inhibition on the bacterial growth plate, whereas the filtered supernatant exhibited no such zone on the growth of E. coli bacteria revealing the fact that lead contamination was removed from the filtered supernatant. The prepared lead oxide nanoplates also possess dye degradation activity which is the added advantage of the process. The MDH1 bacterial protein acts as biological template which successfully removes lead contamination from lead-solution. The process is a clean and cost-effective one which can be used not only for removal of lead contamination but also for removal of different dyes from environment due to having dye-degradation attribute of the lead-oxide nanoplates.