Crustacean shells and wood waste, such as branches cut from trees, usually go to landfills. However, these wastes can gain new life as food additives and medicines through a new process developed by researchers at the National University of Singapore (NUS). Details of the new recycling method are described in an article for Angewandte Chemie International Edition.

A team led by Associate Professor Yan Ning and Associate Professor Zhou Kang from the Department of Chemical and Biomolecular Engineering at the NUS Faculty of Engineering has developed a method to convert shrimp and crab shells into levadopu (L-DOPA), a widely used drug for treating Parkinson’s disease. A similar method can be used to convert wood waste into proline, which is necessary to form healthy collagen and cartilage.

The NUS team’s approach to recycling can play a crucial role in the chemical industry. Searching for and creating compounds from waste is gaining momentum in an effort to reduce reliance on non-renewable fossil fuels and energy-intensive processes.

In general, the global food industry produces up to eight million tons of shellfish waste annually. At the same time, more than 438,000 tons of wood waste was generated in Singapore in 2019, among which are cut branches from trees and sawdust from workshops. The development of ways to process these food and agricultural wastes into useful compounds will be beneficial without burdening the dumps with new waste.

The revolutionary approach of NUS researchers is that they have invented a way of recycling waste that combines the chemical approach with the biological process.

The NUS Research Group led by Associate Professor Yan Ning (left) and Associate Professor Zhou Kang (right) has developed an integrated recycling process to produce valuable amino acids from waste. Submitted by: National University of Singapore.

They first applied chemical processes to waste and turned it into a substance that microbes could “digest”. The second stage involved a biological process similar to fermentation of grapes into wine. Scientists have created special strains of bacteria for transformation of the substance received in chemical process, in more valuable product – amino acids.

It took the NUS team four years to develop their method and apply it to obtain valuable chemicals from renewable sources in an environmentally friendly way.

By the way, the NUS team’s methodology can be applied to different types of waste and they can adapt the process depending on the type of waste as well as the target end product.

Moving forward, the team aims to adapt its unique process to other waste types such as carbon dioxide and waste paper. Such development would reduce society’s dependence on non-renewable resources to purchase chemicals, which are now important components of many food additives and medicines.

The research team also plans to expand the processes currently being developed in their laboratories and work with industry partners to commercialize the technology.