Optimization of the hydrothermal decomposition of Jerusalem artichoke into levulinic acid

In this study, levulinic acid is produced from Jerusalem artichoke (JA, Helianthus tuberosus L.) by hydrothermal decomposition reactions in a batch autoclave reactor. The parameters studied were reaction temperature (T, K), reaction time (t, min), starting material concentration (C), and pH of the aqueous HCl solution (pH_initial) using the Box-Behnken response surface methodology. The highest yield was 35.28% at 165 °C, 89.7 min, 0.5 pH, and 0.045 g/mL concentration within a 95% confidence interval. Dilute feedstock concentrations, low pH of the aqueous acid catalyst solution, and relatively high temperatures should be preferred to maximize the yield LA.

Figure graphical abstract 1. The result of the response optimizer for LA within the studied operating conditions

Figure graphical abstract 1. Variation of organic acid and furfural content, in the liquid product over time at different reaction temperatures at 0.045 g/mL and pH = 1.0

Figure graphical abstract 2. Variation in the yields of organic acid and furfural and sugar compounds in the liquid product over time at different reaction temperatures at 0.045 g/mL and pH = 1.0