Effects of hydrothermal pretreatment of sugar beet pulp for methane production

•The effect of LHW pretreatment of sugar beet pulp on methane fermentation was checked.•The optimum processing condition for hydrothermal pretreatment was determined.•Products of degradation of SBP were analysed.•LHW pretreatment enhancement of methane yield from anaerobic fermentation. The effect of Liquid Hot Water treatment conditions on the degree of sugar beet pulp (SBP) degradation was studied. The SBP was subjected to hydrothermal processing at temperatures ranging from 120 to 200°C. The relationship between processing temperature and parameters of liquid and solid fractions of resulting hydrolysates as well as the efficiency of their methane fermentation was determined. The highest concentration of free glucose (3.29mgml−1) was observed when the hydrolysis was conducted at 160°C (it was 4-fold higher than that after processing at 120°C). Total acids and aldehydes concentrations in the liquid fractions were increased from 0.005mgml−1 for the untreated SBP to 1.61mgml−1 after its processing at 200°C. Parameters of the hydrolysates obtained by the LHW treatment decided of the efficiency of methane fermentation. The highest cumulative methane yield (502.50LCH4kg−1VS) was obtained from the sugar beet pulp hydrolysate produced at 160°C.