Much of the pharmaceutical industry relies on complex molecules built from chemical building blocks. Traditionally, many of these building blocks have come from sources that extract a heavy toll from the environment. Are there more sustainable solutions? At BiOrbic Bioeconomy SFI Research Centre, research is underway to use the milk sugar lactose, a low-value waste product of the dairy industry, to build chemicals that can support modern medicine.

“As a chemist working in a lab, I would previously have ordered my chemicals in from a commercial company without thinking too much about where they came from and whether they were derived from sources with a high carbon cost,” says Professor Pat Guiry, Professor of Synthetic Organic Chemistry at UCD School of Chemistry. “But in the spirit of the Bioeconomy, we need a change of mindset. We need to try instead to use waste material as a starting block for the chemicals we use and reduce our dependence on less sustainable sources.”

Professor Guiry and colleagues in UCD have been looking at dairy waste as a source of useful chemical building blocks. “Lactose is a waste product from milk, it is made up of the sugars glucose and galactose,” explains Professor Guiry. “Chemically speaking, there is a lot of information in there, and we wanted to see if we could use it in other ways.”

His lab, and in particular PhD student Sandra Bulawa, has been using lactose to make chemical structures called ligands, that can bind to metals and catalyse or speed up some types of chemical reactions used in the pharmaceutical industry. 

Her research has resulted in a process to make products in high yields using the right ‘shaped’ ligand, and has shown that lactose is a better starting block than glucose. “That work has been very successful,” says Professor Guiry. “It’s an example of how we can move lactose up the value chain for potential use in the pharmaceutical industry.”

Associate Professor Paul Evans has been looking at another function for lactose: to help deliver anti-cancer drugs specifically to affected cells. “Liver calls have proteins on their surface that bind to carbohydrates such as lactose,” explains Professor Guiry. “So a PhD student in the Evans lab, Morgan Morris, has made a linker molecule that can connect lactose molecules to a drug used to treat liver cancer. The aim is to use lactose to bind the drug to affected liver cells, and so target the anti-cancer treatment to those cells and reduce side-effects.”

And there’s more: Professor Stefan Oscarson’s lab in UCD is making a potential new vaccine against the micro-organism Streptococcus pneumoniae, which can cause pneumococcal disease, using lactose as a building block. “PhD student Dennis Benngtson is making a molecule by linking multiple lactose molecules as subunits, a bit like building up a complicated structure using Lego blocks,” explains Professor Guiry.   

“What these projects have in common is that we are all trying to make something of higher value from lactose,” he says. “This is fundamental research that has the potential to be useful in years to come in the case of vaccines and drugs, and in the shorter term as useful chemicals for the pharmaceutical industry.”