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In this study, the efficient conversion of Helianthus tuberosus L. (Jerusalem artichoke) to sugar, 5-hydroxymethylfurfural (5-HMF), and levulinic acid (LA) were investigated using a Brønsted acid-catalyzed hydrothermal reaction. From this approach, the optimal amounts and reaction conditions for total reducing sugar (TRS), 5-HMF, and LA were as follows: 444 g kg −1 of TRS yield (150.4 °C, 14.6 kg m −3 sulfuric acid, and 9.8 min), 193 g kg −1 of 5-HMF yield (166.0 °C, 4.6 kg m −3 , 30.8 min), and 323 g kg −1 of LA yield (185 °C, 30.8 kg m −3 , 33.7 min). In terms of combined severity, the TRS and 5-HMF concentrations decreased linearly with increasing combined severity, whereas, the LA concentration was increased at a high combined severity factor. The H. tuberosus L. may be useful as a significant feedstock for the production of platform chemicals such as 5-HMF and LA. [ABSTRACT FROM AUTHOR]

Microalgae are renewable, eco-friendly, and sustainable bioresources that have the potential to substitute fuels and chemicals originated fossil resources. The conversion of Chlorella sp. to obtain 5-hydroxymethylfurfural (5-HMF) and levulinic acid (LA) via thermochemical reaction with a metal-sulfate catalyst (Al 2 (SO 4) 3) is introduced here. The statistical approach is introduced to optimize the conversion conditions. By optimization of the 5-HMF yield, about 23.46% of 5-HMF was obtained under 5% biomass amount and 0.75 g-catalyst/g-biomass at 165 °C and 30 min; the highest LA yield of 32.89% was obtained under 2.5% biomass and 1.0 g-catalyst/g-biomass at 205 °C and 60 min. Furthermore, under such harsh temperature condition and high catalyst amount, the maximum 5-HMF yield of 31.46% was obtained at 0 min, which indicates the time required to attain the set reaction temperature. In the evaluation of the catalytic performance via relationship between combined severity factor and 5-HMF/LA, the yields of 5-HMF and LA were demonstrated to be reasonably satisfied for non-linear sigmoidal equations with high regression. Hence, the application of microalgae and metal-salt catalyst has high potential and accessibility in the production of platform chemicals. • Efficient hydrothermal conversion of C hlorella sp. into 5-HMF and LA by metal sulfate catalyst. • 23.46% 5-HMF was obtained under 5% biomass, 0.75 g-catalyst/g-biomass at 165 °C and 30 min. • 32.89% LA was obtained under 2.5% biomass, 1.0 g-catalyst/g-biomass at 205 °C and 60 min. [ABSTRACT FROM AUTHOR]