Anaerobic digestion of food waste using yeast

Fermentative breakdown of food waste seems a plausible alternative to feeding food waste to pigs, incineration or garbage disposal in tourist areas. We determined the optimal conditions for the fermentative breakdown of food waste using yeast (Saccharomyces cerevisiae) in incubations up to 30 days. Yeast efficiently broke down food waste with food waste loadings as high as 700 g FW/l. The optimum inoculation was approximate to 46 x 10(6) cells/l of culture with a 40 degrees C optimum (25-40 degrees C). COD and BOD were reduced by approximate to 30-50%. Yeast used practically all the available sugars and reduced proteins and lipids by approximate to 50%. Yeast was able to metabolize lipids much better than expected. Starch was mobilized after very long term incubations (>20 days). Yeast was effective in breaking down the organic components of food waste but CO2 gas and ethanol production (approximate to 1.5%) were only significant during the first 7 days of incubations. (C) 2015 Elsevier Ltd. All rights reserved.