Biorefineries levulinic acid

Biorefinery includes fractionation for separation of primary refinery products. The fractionation refers to the conversion of wood into its constituent components (cellulose, hemicelluloses and lignin). Processes include steam explosion, aqueous separation and hot water systems. Commercial products of biomass fractionation include levulinic acid, xylitol and alcohols. Figure 3.3 shows the fractionation of wood and chemicals from wood. 

The removal of water from initially formed biomass sugars is an important process for the production of primary biorefinery building blocks. Of particular interest are 5-hydrox-ymethylfurfural and levulinic acid (from the dehydration of glucose or other C6 sugars) and furfural (from xylose dehydration). Recent research has led to new catalytic processes for the production of each of these materials. 

Levulinic Acid. Dehydration of glucose or other monomeric and polymeric C6 sugars leads to the direct formation of levulinic acid (LA) as a potential primary building block for the biorefinery, and several reviews have described its potential commercial utility 477,478 The preparation of levulinic acid is not difficult, although the mechanism of its formation from carbohydrates is complex, and offers several alternative decomposition pathways (equation 3).479... 

Polymeric carbohydrates available from the biorefinery can serve as starting materials for 5-HMF Recently, LaCl3 has been used to catalyze the conversion of cellulose to 5-HMF (along with glucose, levulinic acid, and cel-lobiose) at elevated temperatures in water.489... 

Keywords 5-(Chloromethyl)furfural 5-(Hydroxymethyl)furfural Biomass Biomass derivatives Biorefinery Catalysis CMF Green chemistry HMF Levulinic acid Platform chemicals Renewable chemistry... 

Hayes DJ, Fitzpatrick S, Hayes MHB, Ross JRH (2006) The Biofine process - production of levulinic acid, furfural, and formic acid from lignocellulosic feedstocks. In Kamm B, Gruber PR, Kamm M (eds) Biorefineries - industrial processes and products. Wiley-VCH, Weinheim, pp 139-164... 

Biotechnology continues to be an important contributor to the biorefinery, especially for the conversion of carbohydrates. The paper by Richard describes a new approach for the fermentation of C sugars, providing methodology for more efficient conversion of biomass carbohydrates to EtOH. The contribution from Nakas discusses the bioproduction of polyhydroxyalkanoates using levulinic acid as a carbon source. Stipanovic describes new approaches for using hemicellulose as a chemical feedstock. 

The overall Biorefinery concept is similar to the classical oil refinery model. The low unit cost benefits of economy of scale are obtained by processing of large quantities of feedstock for production of fuels and energy products. At the same time smaller quantities of levulinic acid and other intermediates are diverted into production of higher value added commodity and specialty chemicals making the venture highly attractive financially (29). 

Kamm B, Kamm M (2004) Principles of biorefineries. Appl Microbiol Biotechnol 64 137-145 Keenan T, Tanenbaum S, Stipanovic A, Nakas J (2004) Production and characterization of poly-beta-hydroxyalkanoate copolymers from Burkholderia cepacia utilizing xylose and levulinic acid. Biotechnol Prog 20(6) 1697-1704... 

Hayes, D.J., Fitzpatrick, S., Hayes, M.H., Ross, J.R., 2006. The biofine process-production of levulinic acid, fitffural, and formic acid from lignocellulosic feedstocks. Biorefineries-Industrial Processes and Product 1,139-164. 

Levulinic acid can be manufactured by the acid treatment of starch or the C6-carbohydrates in lignocellulosic biomass via the hydration of hydroxymethylfurfural (HMF), an intermediate in this reaction. A side product of this reaction is formic acid, which is produced in equimolar amounts. It is also possible to produce levulinic acid from the five carbon carbohydrates in hemicellulose (eg, xylose, arabinose) by the addition of a reduction step (via furfuryl alcohol) subsequent to the acid treatment. Levulinic acid has been endorsed as a significant biorefinery building block due to its high yield from six carbon carbohydrates (Bozell and Petersen, 2010). Levulinic acid contains two reactive functional groups that permit a great number of synthetic transformations. 

Besides converting wet biomass into hydrochar, the HTC process is also capable of coproducing chemicals, which include phenolic compounds, 2,5-HMF, and aldehydes (acetic, lactic, propenoic, levulinic, and formic acids) that can potentially be used in biorefineries (Axelsson et al., 2012 Hoekman et al., 2012 Oladeji et al., 2015). The formation and concentration of these chemicals can be controlled by adjusting the HTC process conditions (Libra et al., 2011 Xiao et al., 2012), such as temperature, pressure, and residence time. Therefore the HTC process could be a useful part of biological and thermochemical biorefineries, processing wet residues, and coproducing chemicals and hydrochar. 

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