Pretreatment of agave bagasse with ruminal fluid to improve methane recovery

Agave bagasse, a lignocellulosic waste that results from the milling and juice extraction of Agave tequilana var azul pineapples, is a suitable substrate for the production of methane through anaerobic digestion. However, it is necessary to apply a pretreatment to convert the bagasse into energy. In this context, this paper proposes using ruminal microorganisms to hydrolyze agave bagasse. This study evaluated the effect of the initial agave bagasse to ruminal fluid (S₀/X₀) ratio (0.33, 0.5, 1, and 2) on the hydrolysis efficiency. Subsequently, the supernatant was used for methane production. The hydrolysis efficiency increased as the S₀/X₀ ratio decreased. A hydrolysis efficiency of 60 % was achieved using an S₀/X₀ ratio of 0.33. The S₀/X₀ ratio of 0.33 optimally improved the specific methane production and energy recovery (155 ± 2 mL CH₄/g TS and 6.1 ± 0.1 kJ/g TS) compared to raw biomass. The most abundant hydrolytic bacteria were Prevotella, Ruminococcus and Fibrobacter, and Engyodontium was the most abundant proteolytic fungus.