Anaerobic co-digestion of residual liquors from lignocellulosic biomass fractionation with a synthetic food waste for biogas production

The deconstruction of biomass for the valorization of cellulose through alkaline pretreatment, and the posterior Kraft lignin precipitation using HNO3 generates a residual liquor (RL) rich in sugars and nitrogen compounds. The utilization of this RL for biogas production becomes a sustainable alternative to both treat this byproduct of the biomass deconstruction process and generate renewable and sustainable energy, closing the cycle of the biorefinery process. In this work, the RL of Cannabis sativa L. was used with synthetic food waste (SFW) in a co-digestion process for biogas generation. The results indicated that the addition of RL is directly related to the biogas production and quality, reaching the optimal conditions in the 15% concentration. After this concentration percentage, the yield and quality of biogas decrease with the addition of RL, presumably due to the high concentration of phenolic compounds that inhibit the process.