This research shows that a common mushroom fungus called Trametes versicolor can clean up wastewater produced during the conversion of food waste into biofuel. The fungus transforms hard-to-use nitrogen compounds in the waste into forms that plants can absorb. After three days of treatment, the nitrogen that plants can use increased dramatically. When bacteria known for converting ammonia to nitrate were added to the fungal treatment, the results improved even more, suggesting this waste could eventually be recycled as a fertilizer for growing plants in water-based farming systems.