Turning plant waste into human medicines

Published 02 May 2018

A team of University of New England (UNE) researchers have provisionally patented a chemical breakthrough that allows recycled plant products to be used to make human medicines on a large scale.

The discovery could reduce the environmental cost of making certain pharmaceuticals via petroleum-based processes, as is currently the norm, and allow medicines to be produced more cheaply.

Research group leader Dr Ben Greatrex, of UNE’s Pharmacy and Chemistry department, said the team has shown that abundant and affordable waste materials like sawdust, paper or straw can be used to manufacture classes of HIV drugs, antidepressants and medications to prevent clotting.

The process involves converting the cellulose in the materials into a liquid chemical compound known as levoglucosenone (better known as LGO), which naturally has a property called chirality, or “handedness”.

The term applies to molecules with two sides that are mirror images of each other, like left and right hands. Each side of a chiral molecule has the same chemical properties, but the sides usually behave differently biologically – like a left-handed glove fits poorly on a right hand.

Many modern pharmaceuticals have chiral properties, which makes their synthesis challenging.

“The LGO serves as a template and can tell other molecules how to react,” Ben said.”Some pharmaceuticals have parts of their structure ideally suited to this technology and so we can make them very easily. We have found a way to use LGO from cellulose to prevent a considerable amount of waste from drug manufacturing.”

The research group is working with a Melbourne-based biotech company – The Circa Group – that produces large amounts of LGO using waste sawdust. Using renewable biomass instead of petroleum derivatives has significant advantages.

“Pharmaceuticals with chirality can be difficult to make from petroleum, and separating the unwanted products can be very inefficient and wasteful,” Ben said.

“Our process reduces some of the environmental burden of making medicines and, in future, could result in cheaper medicines. This technology is also scalable and will have wide applicability, making it cost-effective compared to current industrial processes.

“Waste sawdust is very cheap but we can take many waste materials containing cellulose – including old clothes or waste paper, rubbish from cotton processing or sugarcane mulch – and use them to make pharmaceuticals.”

UNE PhD student Julian Klepp, who has joined the research group from Stuttgart, Germany, said while the basic idea is not new, it is novel to be able to make these chemical compounds on a large scale, and to use cellulose in the process.