Fungus process makes ethanol production more efficient

Growing the Rhizopus oligosporus fungus also cleans the water used in the ethanol production process so that it can be recycled back into fuel production. The process, called MycoMeal, could one day produce a low-cost nutritional supplement for people.

For every gallon of ethanol produced, there are about five gallons of leftovers known as stillage. The stillage contains solids and other organic material. Most of the solids are removed by centrifugation and dried into dried distillers grains that are sold as livestock feed, primarily for cattle.

The remaining liquid, known as thin stillage, still contains some solids, a variety of organic compounds and enzymes. But because the compounds and solids can interfere with ethanol production, only about 50 per cent of thin stillage can be recycled back into ethanol production. The rest is evaporated and blended with dried distillers grains to produce dried distillers grains with solubles.

To resolve that issue, the researchers add the fungus to the thin stillage and it feeds and grows into a thick mass in less than a day. The fungus removes about 60 per cent of the organic material and most of the solids, allowing the water and enzymes in the thin stillage to be recycled back into production.