VATIS UPDATE Article

A team of researchers from National University of Singapore (NUS) has discovered that electronic waste is not just a load of garbage. Instead, precious metals such as gold, platinum and palladium can be safely and sustainably recovered from electronic waste. Working together with international collaborators, NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI) researchers found that synthetically engineered microbes can be used to recycle the precious metals. The process, the first such attempt in using synthetic biology for recycling of metals from electronic waste, was developed over a period of three years.

Electronic waste represents a growing portion of unwanted materials in modern cities, posing a major disposal challenge. This presents a pressing need to recycle in order to protect the environment and conserve natural resources. “Ultimately, we can’t continue to mine precious metals such as gold from ores as we’ll run out of these natural resources, so all these circulating metals have to be recovered,” said Associate Professor Yew Wen Shan, at NUS. Supporting this call to recycle is the fact that electronic waste contains a higher concentration of gold compared to gold ores which typically contain other fillers.

The method recovers precious metals, and removes toxic ones such as lead and mercury, in a greener and more sustainable way. Within a bioreactor, the team synthetically engineered a soil bacterium known as Chromobacterium violaceum to produce a biochemical derived from the amino acid glycine. The biochemical oxidises the electronic waste in place of harsh acids used conventionally. Subsequently, another class of engineered enzymes is expressed for biological reduction, effectively substituting electrolysis.