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Sample inhomogeneity is a severe issue in printed circuit boards especially when we are comparing the bioleaching efficiency. To avoid the ambiguous results obtained due to inhomogeneity in PCBs, 12 similar cell phone chargers (of renowned company) having same make and batch number were collected from scrap market. PCBs obtained from them were used in present studies. Out of these 12, three PCBs were used separately for chemical analysis of PCBs with prior acid digestion in aqua regia. It was found that, 10.8, 68.0, and 710.9 mg/l of Zn, Pb, and Cu were present in it, respectively. Six PCBs were used for bioleaching experiment with two variations, pulverized and non-pulverized. Though the pulverized sample have shown better leaching than non-pulverized one, former has some disadvantages if overall recycling of e-waste (metallic and nonmetallic fraction) is to be addressed. At the end of leaching experiments, copper was recovered using a simple setup of electrodeposition and 92.85% recovery was attained. The acidophiles involved in bioleaching were identified by culture dependent and culture independent techniques such as DGGE and species specific primers in PCR.

A rosin glycerol derivative was prepared by esterification of rosin with glycerol at 220-240°C in the presence of zinc as catalyst. The product was evaluated for different physicochemical properties. Films were prepared by melt molding with castor oil (20% w/w of the derivative) as an external plasticizer. The in vitro and in vivo biodegradation studies were performed on films as well as on powder. The in vitro studies were performed with microorganisms, enzymes and different buffer solutions while in vivo studies were performed on rabbits by subdermal implantation of rosin ester films. The results of all the studies showed that rosin glycerol ester undergoes biodegradation and follows surface erosion mechanism.

Many microorganisms produce intracellular metal nanoparticles. Aqueous gold, when exposed to several actinomycetal strains, become thereby, leading to the formation of gold nanoparticles. The use of microorganisms in the synthesis of nanoparticles is emerging as an eco-friendly and exciting approach gold for recovery. Streptomyces hygroscopicus was used for the biosynthesis of gold nanoparticles. UV and visible spectroscopic studies of biofilms revealed better synthesis of nanoparticles. It was observed that better biosynthesis of gold nanoparticles occurred when cell biomass treated with 10 -3 and 10 -4 mM HAuCl 4 solution as compared to other dilutions. The pH 7.0 was found to be optimum for the biosynthesis of gold nanoparticles. The TEM study revealS that there was evidence of gold nanoparticles synthesized by S. hygroscopicus. The results demonstrate that spherical gold nanoparticles in the range of 10 to 20 nm were observed at pH value of 7.0. The actinomycetal biomass and various concentration of aqueous HAuCl 4 solution were incubated, it was found that 10 -4 concentration shows excellent colour of the actinomycetal biomass.