With rapid global advancement and an exponential growth rate in the electrical and electronic industries in the 21st century has come a disaster change in consumer lifestyles, resulting in the generation of a huge amount of obsolete electronics/e-waste (Perez-Belis et al. 2017). It has been estimated that approximately 42 million tons of e-waste is generated globally per annum (Balde et al. 2017). The latest estimates indicate that in 2020 almost 90–100 million tons of e-waste will be generated globally (U.S.EPA, 2015). Managing the rapidly growing volume of e-waste is a major challenge for most of the countries today. The first major problem associated with e-waste management is its ever-increasing quantum, and the second is its scientific and environment-friendly disposal, which is very crucial (Wath et al. 2017). A number of electronic components such as computer’s keyboard, instrument housing, covers, printed circuit boards etc., are constructed from valuable engineered plastics. Due to difficulties associated with their separation, sorting and collection, a significant proportion of them is generally reused in low-value applications (Wu et al. 2016). Several billion tonnes of waste plastics are expected to be produced from e-waste alone during the next decade. Polymers represent approximately a 20% of the total e-waste stream and include some 15 different types, such as polycarbonate (PC), copolymer of acrylonitrile-butadiene-styrene (ABS), high impact polystyrene (HIPS), polyamides (PA), polypropylene (PP), polyethylene (PE), polyurethane (PU), polyvinyl chloride (PVC), polyesters, etc. which are mostly thermoplastics (Martinho et al. 2012; Vazquez and Barbosa, 2015). These Synthetic polymers have inspired a broad range of applications because of their design flexibility, strong mechanical strength and solution processability (Sun et al. 2017). Dioxides and furans, which are considered to be carcinogenic, are released into the environment in large quantities during incineration.
Nonetheless, the recycling rate of such waste plastics is still quite low as it sometimes costs more to recycle than the value of the recycled material/product itself. Due to its hazardous nature, landfilling or dumping of e-waste is highly undesirable. Poor recycling techniques, especially in the developing and transient economies, generate high levels of environmental pollution in the vicinity of main recycling areas (Widmer et al. 2015). Informal e-waste recycling approaches include techniques such as manual dismantling, plastic chipping and melting, and several inadequate metallurgical treatments (Bhutta et al. 2011). These processes release dust particles loaded with heavy metals and flame retardants into the atmosphere that can lead to environmental pollution over extended regions (Robinson et al. 2015; Mielke et al. 2013; Bridgen et al. 2011). Moreover, chemical processes using strong acids are hazardous as well as expensive for treatment, therefore, biological approaches using microorganisms, earthworms and plants are valuable alternatives to traditional methods (Patel and Kasture, 2014). Hence, microbial approach toward this issue can be a better option in the current situation (Mohan et al. 2017).
In the past, some studies with microorganisms have been conducted to explore biotreatment of e-waste, with the expectation that they may lead to the development of more efficient and less costly processes. Though, majority of these works deals with the bioleaching and recovery of the precious metal present in the e-waste. However, significantly a novel bacterium Ochrobactrum sp. T was isolated and tested for its ability to effectively degrade TBBPA (Tetrabromobisphenol A) which is a brominated flame retardant widely used in consumer electronics, primarily in the plastics; the microorganism successfully degraded TBBPA, and used TBBPA as a sole carbon and energy source under aerobic conditions in water (An et al. 2011). In recent years, variety of polymers viz. PVC, LDPE, HDPE, HIPS, etc. were studied for the biodegradation using different microorganisms by several research groups (Satlewal et al., 2008; Soni et al. 2009; Kapri et al. 2009, 2010 a, b; Sah et al. 2010, 2011; Shekhar et al. 2016; Mohan et al. 2016).
In the above context, the present study is planned to isolate indigenous microbial strains that are having potential to degrade e-waste plastics particularly computer’s keyboard and to formulate their consortia with suitable carriers for performing the in situ biodegradation studies. The aim of formulating viable cells in carriers is to facilitate the delivery and handling process, and to ensure the adequate cell viability to maintain the efficacy of the cells (Bazilah et al., 2011). The selection for the type of formulation developed and used is dependent on the nature of active cells and the factors related to the site of application (Goel et al., 2012). Therefore, present investigation is a step forward to develop an effective, economic and sustainable way to deal with the e-waste pollution in the future.