Methane Fermentation of Coffee Grounds and Some Factors to Improve the Fermentation

Abstract

The efficiency of methane fermentation of coffee grounds was increased by pretreatment with dioxane, followed by incubation with cellulo- and hemicellulolytic enzymes. Gas production from coffee grounds thus treated and fermented with a supply of a small amount of L-glutamine and inositol amounted to nearly 335 ml per g coffee grounds with a methane ratio of 58%. This gas production was 2.2 times higher than that from intact grounds.
Acetic, propionic and butyric acids considerably accumulated in the mash containing L-glutamine and inositol after 3 days of incubation and decreased gradually during the fermentation process. Isobutyric acid accumulated at a later period.