Extended Spectrum Beta-Lactamase Expressing <i>Chromobacterium</i> Sp. Dyh27s2016 Strain is Capable of Metal Leaching in Electronic Waste

Abstract

Printed circuit boards (PCBs) contain many precious and hazardous metals, and the disposal of a large number of electronic wastes (e-waste) has been a serious environmental concern. The conventional metallurgy methods used to recover metals from e-wastes require higher energy expenditure besides contributing to significant environmental pollution. This necessitated an alternative approach, such as using cyanogenic and other environmental bacteria to recover metals from e-waste. Hence, the current study is aimed to explore the feasibility of Chromobacterium sp. Dyh27s2016 strain in mobilising metals from e-waste. A two-step bioleaching process was employed with the ATCC culture Chromobacteriumviolecium Bergonzini (12472TM) used as a control. The metal content in the supernatant was analysed using the inductively coupled plasma - optical emission spectrometry (ICP-OES) technique. Meanwhile, the metal concentration in PCBs was also assessed using the acid reflux method followed by the ICP-OES analysis. Besides, the Chromobacterium sp. Dyh27s2016 strain was also assessed for the beta-lactam antibiotics resistance and the gene expression for extended spectrum beta-lactamase (ESBL). It was observed that Chromobacterium sp. Dyh27s2016 strain mobilises 80, 94, 52 and 56% of Cu, Fe, Zn and Ag respectively from e-waste. However, this strain was found resistant to penicillin G sodium, ampicillin sodium and ticarcillin disodium but susceptible to cefotaxime sodium antibiotics. The molecular analysis showed that this strain possessed the ESBL genes, TEM and CTX-M. The findings from this study enable potential industrial applications for recycling electronic trash using Chromobacterium Dyh27s2016 strains in future.