In vitro studies on nanoparticle mediated biodegradation of electronic waste by native bacteria

Abstract

The management of electronic waste (e-waste) becomes a global issue in this newlinedigital era. Plastics are neither the main residue nor the most important pollutant in newlineelectronic trash, but they take up a lot of room due to their low density and the forms of newlinetheir parts. They make up about 17 percent of the WEEE (Waste from Electrical and newlineElectronic Equipment) stream. More than 55% of all the polymers in e-waste are made up newlineof ABS (Acrylonitrile Butadiene Styrene) and HIPS (High Impact Polystyrene Sheet). newlineExisting conventional practices are harmful for dealing with e-waste, therefore, indigenous newlinesoil bacteria were explored for e-waste treatment through enrichment culture approach newlinefollowed by screening, identification and their characterization used for in-vitro newlinebiodegradation investigation. Soil bacteria were enriched in the presence of e-waste for 6 newlinemonths and the findings were established through optical density value that were higher in newlinethe case of soil enrichment than the control. Based on their morphological, biochemical and newlinemolecular characterizations, the bacterial isolates MGP1, MGP4 and MGP15 were newlineidentified as Bacillus aryabhattai, Sporosarcina sp., Rhodococcus kroppenstedtii. The newlineselection and biocompatibility testing of potential isolates were performed for the newlineformation of bacterial consortia. All the isolates displayed their best performance at pH 7, newlinetemperature 30°C and shaking speed 120 rpm. Supplementing the nutrient medium with newlineadditional carbon and nitrogen sources enhanced the rate of polymer degradation by the newlinebacterial isolates. A known bacterial strain Pseudomonas fluorescens was selected for the newlinedegradation of the electronic waste and its comparison with that of screened bacterial newlineisolates. Comparative studies showed that e-waste degradation potential of consortium is newlinebetter than the individual bacterial strains. Titanium Dioxide (TiO2) nanoparticles were newlineused to study its effect on biodegradation ability of the best suited bacterial strain. newlineThe biodegradation of e-waste by the selected strains during in vitro experiment newlinewas confirmed by analytical processes like FT-IR, FESEM, EDX elemental analysis. Thus, newlinethis study besides providing direct and standardized protocol for screening and selection of newlineefficient e-waste utilizing bacteria is also demonstrating potential consortia which are ready newlineto be used. The bacterial isolates were able to degrade e-polymer both in media and soil newlineand therefore can be used profitably for field scale bioremediation technology. newline