Submit Manuscript | http://medcraveonline.com Introduction Rapid urbanization, industrialization, and population growth have resulted in increased demand of electronic and electrical gadgets. With fast technological advancement and development, due to the demand of people, industries are now manufacturing novel, superior and smart electronic and electrical equipments (EEEs) at an alarming rate. More and more EEEs products are produced, purchased, used and discarded resulting in the generation of huge amount of waste electronic and electrical equipments (WEEEs). 1 The electronic waste (e-Waste) normally consist of small and large equipment such as LED lamps, cell phones, smart mobile phones, superior televisions, refrigerators, printers, driers, temperature exchangers as well as advance computing devices. 2 Due to the fast advancement in technology and tremendous market growth most of these electronic and electric material have very short life span, which resulted in the fastest accumulation in e-Waste. 3 Broadly, the end of life electrical and electronic equipments without intent of reuse is considered as e-Waste. As per the information available in literature in 2014, about 41.8 million tons of e-Waste generated globally and as per the estimation e-Waste is growing at the rate of 4-5% annually, which leads to about 49.8 million tons of e-Waste generation in 2018. 4 The large amounts of complex and diverse e-Waste generated have adverse impact on environment as well as human being, if they are not properly managed. Unfortunately there is no proper system to collect, store, transport, treat, and disposal of e-Waste. Thus, it has become major issue of concern for the industries, government and non-government organization and even for the public to protect the environment from the hazardous effect of improperly managed e-Waste. 5 Most of us know that e-Waste has been accumulated since many years, but their devastating environmental effects is realized recently, which has created keen awareness in the scientifc community as well as in common people throughout the world and it has forced concerned peoples for their proper treatment. E-Waste has been accumulated since many years; contain several hazardous organic pollutant as well as considerable amount of base, precious and rare earth metals. 6 The core component of all electronic and many electrical equipment is printed circuit boards (PCBs), which is used for smooth, fast and convenient functioning of small to large electronic devices. PCBs contain several metals as well as various organic pollutants. Thus, it cannot be dumped as landfll or incinerated. However, incineration and land flling are the common method adapted for e-Waste management, which leads to the release of toxic gases in atmosphere and highly harmful metals in soil and ground waters. These pollutants will accumulate and transport in plant systems, which ultimately reach to animals and human. 7,8 Due to this awareness e-Waste management has become a vital and signifcant feld of research throughout the world. The current chapter mainly focus on bio-treatment of PCBs with special reference to extraction of metals from waste PCBs by using microbial technology. Types of microorganisms involved in the metal solubilisation process and major mechanisms of metal extractions are illustrated. e-Waste and printed circuit boards (PCBs) Asian countries like India and China are the major countries, which get the e-Waste from all over the world for recycling purpose as the developing countries have less legislation rules for disposal. 9 There are several defnitions for e-Waste, but the simplest defnition for e-Waste is “any broken or unwanted electronic and electrical appliances/equipments”. According to European Union, 10 any J Bacteriol Mycol Open Access. 2018;6(4):241‒247. 241 ©2018 Dave et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and build upon your work non-commercially. Microbial technology for metal recovery from e-waste printed circuit boards Volume 6 Issue 4 - 2018 Shailesh R Dave, 1 Asha B Sodha, 2 Devayani R Tipre 2 1 Department of Forensic Science, School of Sciences, Gujarat University, India 2 Department of Microbiology and Biotechnology, School of Sciences, Gujarat University, India Correspondence: Shailesh R Dave, Department of Forensic Science, School of Sciences, Gujarat University, India, Email shaileshrdave@yahoo.co.in Received: May 26, 2018 | Published: July 23, 2018 Abstract End-of-Life Electrical and Electronic Equipments commonly know as e-waste is an emerging problem with developed as well as developing nations. Our obsession on electrical and electronic equipments, the unquenchable desire for latest devices and rapid advances in technology has resulted in the world wide generation of huge amount of e-waste. Printed circuit boards (PCBs), the core processing unit of electronic devices contain complex mixture of ceramics, metals and polymers. PCBs are considered as secondary source of several metals. Only a small fraction of this being treated or recycled properly; lion share of e-waste is dumped as landflls or incinerated. Till date no standard eco-friendly technique is available for their safe disposal. In recent decades signifcant attempts have been done for developing pyrometallurgical and hydrometallurgical technology for recovery of metals from PCBs, but these processes are also non sustainable due to secondary pollution they create and they are cost intensive. Microbial biotechnology, based mainly on the potential of microorganisms to generate lixiviants which mobilize metals from PCBs. Iron and sulphur oxidizing bacteria generate ferric iron and protons which extract several metals in aqueous phase. Cynogenic microorganisms are effectively used extraction of gold and silver from PCBs. Some fungi are also reported for metal solubilisation from PCBs by generating organic acids. This technology is considered a novel approach to mobilize metals from various types of PCBs. The main advantage of microbial technology would it can work with dilute waste streams, work at ambient temperatures and pressures, it is cost effective, reduce environmental impacts and generate minimum secondary waste. Thus, this chapter explores furnish and the details on microorganism based technology for extractions of base and precious metals from e-waste PCBs. Keywords: biomining, e-Waste, PCBs, bioleaching, microbes Journal of Bacteriology & Mycology: Open Access Review Article Open Access