2025 AIChE Annual Meeting

(402h) Effect of Chemical-Free Hydrothermal Pretreatment on Recovering Cellulosic Sugars and Pectin from Sugar Beet Pulp

Authors

Armando McDonald, University of Idaho
Vijay Singh, University of Illinois at Urbana-Champaign
Sugar beet pulp (SBP), a byproduct of sugar production from sugar beets, is a promising feedstock for high-value bioproduct production. SBP consists of cellulose (22–30%), hemicellulose (24–32%), pectin (15-32%), lignin (3-6%), ash (3-5%), lipid (1-2%) and a small amount of protein [1]. Due to its abundant carbohydrate content, SBP has been widely used in the production of biodegradable polymers, functional food ingredients, and biofuel [2]. Moreover, its high pectin content makes it suitable for prebiotic and pharmaceutical applications, contributing to a sustainable waste valorization pipeline. Feedstock pretreatment plays a crucial role in enhancing the recovery of valuable components from SBP. Hydrothermal pretreatment has been used to deconstruct diverse feedstocks due to its flexibility and economic feasibility [3]. This study investigates the effects of chemical-free hydrothermal pretreatment on recovering cellulosic sugars and pectin. Specifically, it examined how pretreatment temperatures (80, 100, 120°C) and reaction times (15, 30, 45 minutes) influence the extraction of fermentable sugars and pectin. Results showed that increasing pretreatment temperature and time led to a rise in extractives (from 45% to 60%) and a decrease in galacturonan (from 12% to 8%), with a minimal impact on cellulose and other biomass components. Pretreatment under 100-120°C for 30-45 minutes resulted in the best glucose yield of (82-90%) and total pentose yield of (85-90%), while galacturonan remained in the residual solids after enzymatic hydrolysis. The residual solids were then subjected to subsequent pectin extraction with dilute acid at 60-80°C for one to three hours. An optimal pectin yield of over 85% was achieved at a temperature over 70°C with a reaction time of 2 hours, indicating potential reduction in chemical and energy consumption compared to the conventional industrial extraction method [4]. These findings highlight that chemical-free hydrothermal pretreatment not only enhances the recovery of cellulosic sugars but also serving as an effective prerequisite for pectin extraction by minimizing chemical usage and and process time.

Keywords: Chemical-free hydrothermal pretreatment; Fermentable Sugars; Galacturonan; Pectin.

Reference

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  2. Usmani, Z., Sharma, M., Diwan, D., Tripathi, M., Whale, E., Jayakody, L. N., Moreau, B., Thakur, V. K., Tuohy, M., & Gupta, V. K. (2022). Valorization of sugar beet pulp to value-added products: A review. Bioresource Technology, 346, 126580. https://doi.org/10.1016/j.biortech.2021.126580.
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  4. Adiletta, G., Brachi, P., Riianova, E., Crescitelli, A., Miccio, M., & Kostryukova, N. (2020). A Simplified Biorefinery Concept for the Valorization of Sugar Beet Pulp: Ecofriendly Isolation of Pectin as a Step Preceding Torrefaction. Waste Biomass Valor 11, 2721–2733 . https://doi.org/10.1007/s12649-019-00582-4.