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 (pHinitial) using the Box-Behnken response surface methodology. The highest yield was 35.28% at 165 degrees 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.Graphical AbstractFigure graphical abstract 1. The result of the response optimizer for LA within the studied operating conditionsFigure 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 = 1.0Figure 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 = 1.0Graphical AbstractFigure graphical abstract 1. The result of the response optimizer for LA within the studied operating conditionsFigure 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 = 1.0Figure 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 = 1.0Graphical AbstractFigure graphical abstract 1. The result of the response optimizer for LA within the studied operating conditionsFigure 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 = 1.0Figure 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