Tofu production generates both solid and liquid waste. Cows and other ruminants can be fed tofu slurry, which is solid tofu waste. What about liquid waste? Biogas can be produced from liquid waste by using microbial processes to convert liquid tofu waste into biogas in a bioreactor.

Tofu waste has great potential for biogas production due to its high protein and organic content. One study suggests that the liquid waste from tofu production contains significant amounts of organic matter, making it a viable alternative fuel source through anaerobic digestion. Another study found that by adding solid tofu waste and using microorganisms from cow manure, a significantly larger volume of biogas could be produced in just 7 days, reaching up to 715 ml.