Using Yeast to Convert Waste into Fuel

Teresa Madaleno

After three long years of study, a group of scientists in Singapore have found a way to use yeast to convert food waste into fuel.

They have genetically modified yeast that can convert fats in food waste in order to recover half its weight in butanol. Butanol is an alcohol that can be used as fuel. This means over 600,000 tonnes of food waste that is normally incinerated in Singapore every year will have a second life.

The team from National University of Singapore Synthetic Biology for Clinical and Technological Innovation modified the yeast known as, “Yarrowia lipolybica” by inserting 10 extra genes cells into it. According to, the extra genes enable the yeast to recover half of the waste’s weight in butanol.

The Singapore scientists report, the process uses 4 times less carbon dioxide than incineration.

Doctor, Don Matthew Chang, a professor at the University of Singapore was the project leader. Here’s what he said to reporters when announcing the breakthrough: “Not only can we reduce the amount of food waste that gets burnt, but we can also produce a high-value product that has a global demand of 350 million gallons a year.”

Chang’s team uses a method that blends the food waste, and extracts the fats then adds it to the engineered yeast in a bioreactor. Butanol is then filtered out.

Now that this system has worked in the laboratory, the research team is looking for funding to test it on a larger scale.