A renewable strategy for producing levulinic acid from wheat straw as sustainable lignocellulosic biomass

Abstract

Levulinic acid (LA) is one of the top 12 value-added versatile chemicals and basically used to synthesize diverse range of products such as chemicals, fuels, and polymers. Developing sustainable routes for the production of levulinic acid using lignocellulosic biomass is an important research area. The current study demonstrates the direct usage of monosaccharides that are obtained following ultrasound assisted alkali pretreatment of wheat straw for the synthesis of levulinic acid also elucidating the effect of various operating factors of the hydrothermal conversion process on LA yield. The range of operating parameters investigated in the study include time (0–120min), temperature (140–180 °C), solid loading (4–10 %), agitation speed (200–450 RPM), acid concentration (3–8 %), and type of acids (HCl, H₃PO₄, H₂SO₄). The optimal parameters established in the study included temperature of 170 °C, 5 % sugar loading, and 4 % H₂SO₄ concentration that resulted in the highest levulinic acid yield (63.5 %) during 120 min, with nearly complete sugar conversion. The current study clearly revealed the sustainable conversion of wheat straw into levulinic acid with a demonstration of the best operating conditions during the hydrothermal conversion process for maximum LA formation.