Thermo-alkaline pre-treatment to solubilise and improve biodegradability of press mud

Thermo-chemical pre-treatment improves the solubilization of the lignocellulosic biomass. Therefore, it could improve biogas production from press mud, the solid residue from sugar cane juice filtration which contains up to 85 % insoluble organic matter. The impact of thermo-alkaline pretreatment conditions (100 o C, Ca(OH)2) on press mud was investigated for different times and concentrations, thus different pretreatment severities. The biochemical methane potential (BMP) was determined in batch assays under mesophilic conditions (37 ± 1 o C). The best treatment resulted in 72 % of methane yield in surplus, adding 10 g Ca(OH)2 100 g -1 TS -1 for 1 h. Pretreatment also increased the solubilization of the chemical oxygen demand (COD), but the optimal severity for COD solubilization did not ensure the highest methane production. Inhibitory effects on anaerobic digestion were noticed when severity was increased. These results show the importance of thermo-alkaline pretreatment severity both in terms of concentration and reaction time to obtain optimal anaerobic biodegradability of lignocellulosic biomass.