Researchers in Switzerland have come up with a promising new use for glycerol, a waste byproduct in the production of biofuels.
Scientists at ETH Zürich have been working on an eco-friendly process to convert the substance into lactic acid, an important platform molecule in the manufacture of bio-chemicals.
Among the potential applications of lactic acid is the production of polylactic acid (PLA), a degradable plastic used to make disposable cups, bags and other forms of packaging. Using waste feedstock to produce bioplastics would make the resulting products greener than ever.
According to the university, the method developed by the research groups of ETH professors Konrad Hungerb¸hler and Javier Pérez-RamÌrez at the Institute for Chemical and Bioengineering is more productive, cost-effective and eco-friendly than sugar fermentation, which is the technology currently used to produce lactic acid.
Glycerol is becoming more and more abundant, with the volume estimated at 3 megatons in 2014 and growing to over 4 megatons by 2020.
"Nobody knows what to do with this amount of waste glycerol," commented Merten Morales, a PhD student in the Safety and Environmental Technology group of Professor Hungerbühler.
Its impurity makes the substance unsuitable for the chemical or pharmaceutical industry. Glycerol is also not a good energy source.
"Normally, it should go through wastewater treatment, but to save money and because it is not very toxic, some companies dispose of it in rivers or feed it to livestock. But there are concerns about how this affects the animals," Morales added.
In the new process, glycerol is first converted enzymatically to an intermediate called dihydroxyacetone. This is further processed to produce lactic acid by means of a heterogeneous catalyst.
The findings of the study have been published in the journal Energy & Environmental Science.