Biomass sugar platform

Polyols An Alternative Sugar Platform for Conversion of Biomass to Fuels and Chemicals... 

Our research has established a clean fractionation of biomass carbohydrate polymers into monomeric polyols which serve as a new alternative sugar platform. Polyols are obtained from biomass by chemical means, rather than by enzymatic degradation, and are further transformed by chemical means into quality fuels and other chemicals. 

Biomass can be converted into biofuels via two main types of processes thermochemical and biochemical/biological conversion (Huang and Yuan, 2015). The typical products of the thermochemical conversion process include syngas, bio-oil, and biochar and the products of the biochemical conversion process are bioalcohols, carbohydrates, and lignin. Our concern in this chapter is biochemical production of bioalcohols, or biorefinery process through the well-known sugar platform. ... 

When the structure of biomass components has to be quite drastically rearranged compared to the building blocks needed, synthesis gas or different sugars can serve as platform chemicals. The latter can be converted, for example, to sugar-derived building blocks (Figure 2.2.3) - that is, to glycerol, sorbitol, levulinic acid, and furfural. 

Since so many detailed reviews are available [5-15], in this contribution we only tabulate data for the best published outcomes under each of the below mentioned representative approaches to HMF synthesis, involving fructose, sugars other than fructose (glucose or sucrose), inulin, cellulose, and finally biomass itself (Table 1). This is followed by a brief discussion of the respective advantages and practical limitations of the feedstocks, catalysts, and media. We then also give highlights of the derivative chemistry of HMF and discuss its future prospects as a renewable platform chemical. 

Concentrated sulfuric acid has been used to dissolve and hydrolyse native cellulose (see Figure 7.6). The concentrated acid can disrupt hydrogen bonding between the cellulose chains and thus decrystallize the eellulose. Then, water is added to rapidly hydrolyse cellulose into glucose. The diluted sulfuric acid is re-concentrated for the next eyele of decrystallization and hydrolysis steps. The final produets inelude a mixture of C5 and C6 sugars. The hydrolysis proeess is generally more complex than pyrolysis or liquefaction. However, hydrolysis enables selective decomposition of the biomass polymers and thus provides access to useful platform chemicals that are unavailable from pyrolysis or liquefaction techniques. 

Platform compounds are further converted to products by microbial fermentation processes. Saccharification and fermentation can be accomplished in a sequential process by separate hydrolysis and fermentation (SHF), or in a consolidated one-pot process known as simultaneous saccharification and fermentation (SSF) of single sugars or simultaneous saccharification and co-fermentation (SSCF) of all monosaccharides. Future developments might even combine the production of saccharolytic enzymes, the hydrolysis of cellulose, and hemicellulose to monomeric sugars and the fermentation of hexose and pentose sugars in a single process, the so-called consolidated biomass processing (CBP) (Menon and Rao 2012). 

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