Integrated Renewable Production of Sorbitol and Xylitol from Switchgrass

Abstract

This work deals with the design of integrated facilities for the production of xylitol and sorbitol from lignocellulosic biomass. Xylitol can be obtained from xylose via fermentation or catalytic hydrogenation. Sorbitol is obtained from glucose, but preferably from fructose, also via fermentation or catalytic hydrogenation. Fructose can be obtained from glucose via isomerization. Thus, a superstructure of alternatives is formulated to process switchgrass, corn stover, miscanthus, and others agricultural and forestry residues. Different pretreatments, such as dilute acid or AFEX for the fractionation of the biomass are evaluated. Next, after hydrolysis, the C5 and C6 sugars are processed separately for which a catalytic or a fermentation stage are considered. Glucose is to be isomerized before it can be processed. Finally, crystallization in a multistage evaporator system is used for purification. The optimization of the system suggests the use of dilute acid and the catalytic system. A system of 3 crystallizers is selected. For a facility that produces 145 kt/yr of xylitol and 157.6 kt/yr of sorbitol, the investment adds up to 120.74 M€ for a production cost of 0.28 €/kg of products. The inverse engineering of biomass was also performed resulting in a composition of 15% water, 20% cellulose, 40% hemicellulose, 15% lignin and 5% ash. The closest biomass corresponds to Sargassum (brown algae), that is capable of producing 230.5 kt/yr of xylitol and 116 kt/yr of sorbitol with investment and production costs of 120.5 M€ and of 0.25 €/kg of products, respectively.

Sorbitol production from mixtures of molasses and sugarcane bagasse hydrolysate using the thermally adapted Zymomonas mobilis ZM AD41

“…In the food industry, sorbitol can be used not only as a sweetener but also as a texturizer, moisturizer, and softener. Sorbitol has been used in dietetic foods for diabetic patients since its metabolic pathway is noninsulin-dependent 5 . Due to high demand, the global production of sorbitol is estimated to be approximately 2 million tons per year, and its market is continuously increasing 6 .…”

“…Renewable biomass has emerged as a high-potential feedstock for producing bioenergies, biopolymers, and several other platform chemicals and added-value products through the biorefinery concept. In the past decade, sorbitol has been primarily produced via chemical processes, mainly through catalytic hydrogenation of glucose 5 , 7 , 8 or via biological fermentation of sucrose or a mixture of sucrose and maltose or glucose and fructose 9 – 12 . Due to the negative environmental impact of the chemical process and the high cost of the sugar materials used in biological fermentation, the biological production of sorbitol using low-cost and abundant renewable biomass, specifically byproducts from the agricultural industry, has received significant attention.…”

Optimal Integrated Plant for Biodegradable Polymer Production

“…In addition to biodegradable polymers, it is important to focus on the synthesis of polymers from renewable resources and wastes to reduce their CO 2 footprint and promote the principles of circular economy and the targets of the agenda 2030 of the United Nations . The waste to chemicals initiative aims at producing added value products from waste biomass, and polymers qualify within this set of products including food additives, active principles in drugs, , and platform chemicals …”

“…12 The waste to chemicals initiative aims at producing added value products from waste biomass, 11 and polymers qualify within this set of products including food additives, active principles in drugs, 13,14 and platform chemicals. 15 For instance, the polymers presented in previous work 10 required several raw materials including sawdust, glycerol, and starch. Sawdust is a byproduct or a residue from the forest industry, glycerol is the byproduct of the production of biodiesel, 16 and starch is a constitutive of cereal grains or algae.…”

“…12 The waste to chemicals initiative aims at producing added value products from waste biomass, 11 and polymers qualify within this set of products including food additives, active principles in drugs, 13 , 14 and platform chemicals. 15 …”