Biomass derived components

The introduction of biomass-derived components or even substitution fuels may help to alleviate the dependency on oil and to control fossil carbon dioxide emissions from transport, provided some conditions are respected ... 

The introduction of biomass-derived components has been proposed for more than a century ... 

Biomass is built-up mainly out of the elements C, H and O, just like many of our current fuels and chemicals, although the C-H-O ratio differs significantly, as will be discussed later. The proof of principle for the conversion of biomass into single components or mixtures that can be blended with fossil fuels or that can replace fossil fuels has been delivered already. Table 6.1 lists fossil fuels that are in use today and their possible biomass derived fuel equivalents. 

Some biomass-derived contaminants, on the other hand, may affect the catalytic processing rate. Ammonium shows significant inhibition calcium may also have an effect. Potassium, though, appears to have too little interaction to be noticeable at the concentrations tested. The common acid anions phosphate, sulfate, and chloride appear to have no effect, while nitrate changes the conversion route and the product slate through a sugar isomerization mechanism. These tests show that while some contaminants may affect the catalytic processing rate, most have no impact, and there is no indication of a combinatorial effect on the catalyst when several of the contaminants are present in the feedstock. Consequently, the calcium and ammonium continue to be the key components of concern. 

Research to improve ethanol fermentation has also focused on the development of a high solids, continuous feeding process as well as improved yeast strains. Other related developments include processes for the use of biomass feedstocks, such as cellulosic waste material.40"44 The Genencor-NREL collaboration funded by the U.S. DOE has (a) put in place the tools required for continual improvement of biomass-derived cellulases, (b) built a suite of enzymes with enhanced thermostability and improved specific performance at elevated temperatures, (c) developed an improved production strain for the enhanced cellulase components and demonstrated an enhanced production process. Therefore, plans are in place to provide a developmental product(s) in support of continued industry development. 

The liquid portion of biomass-derived process samples may also contain carbohydrate degradation products, such as 5-(hydroxymethyl)-2-furaldehyde (HMF), levulinic acid, and furfural, as well as other components of interest, such as organic acids and sugar alcohols. Portfolio methods are available for the quantitative measurement of these degradation products and byproducts of polymer hydrolysis. 

Microbial processing by direct fermentation of primary biomass derivatives such as glucose can be used to synthesize a large number of organic chemicals. The cellular components that facilitate these processes are enzymes, the protein catalysts produced by the microorganisms. Some examples of direct fermenta-... 

TABLE 13.7 Examples of Organic Chemicals Produced by Fermentation or Enzyme-Catalyzed Conversion of a Biomass Component, Primary or Secondary Biomass Derivative, or Other Organic Chemical ... 

Liquefaction processes for biomass conversion can be categorized as slurry-phase. high-pressure processing, usually with catalysts or as dry pyrolysis at low or reduced pressure. The research has concentiated on the fuel properties and has often overlooked tiie detailed chemical analysis of the biomass-derived products. Both process types produce a complex mix of oxygenated organic components. The... 

The oxidative dehydrogenation of alcohols represents key steps in the synthesis of aldehyde, ketone, ester, and acid intermediates employed within the fine chemical, pharmaceutical, and agrochemical sectors, with allylic aldehydes in particular high-value components used in the perfume and fiavoring industries [1]. For example, crotonaldehyde is an important agrochemical and a valuable precursor for the food preservative sorbic acid, while citronellyl acetate and cinnamaldehyde confer rose/fruity and cinnamon flavors and aromas, respectively. There is also considerable interest in the exploitation of biomass-derived feedstocks such as glycerol (a by-product of biodiesel synthesis from plant or... 

Figure 9.1 The concept of single-cell biorefinery. A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power, heat, and value-added chemicals from biomass. A single-cell biorefinery, in our views, is a single-cell factory that can produce multiple products from biomass or its various derived components. The orthogonal design of substrate-product metabolism does not interfere with the host cell s native interactome. Hence, the simultaneous production of different compound can be simply maximized by forward engineering principles with high accuracy of prediction.

There are several examples describing the production of multiple compounds from biomass, or its derived components (Table 9.2). Dairy manure is a type of biomass that contains 12% hemicellulose, 22% cellulose, and 18% crude protein, representing a lai e potential source of carbohydrates as a carbon source and proteins as a nitrc en source. This substrate is uniquely adaptable and advant eous for animal manure refineries. The Rhizopus oryzae ATCC 20344 cell factory produced fumaric acid and chitin fiom the dairy manure. A liquid/ solid separation was used to obtain a nitrc en-rich liquid stream for fungal growth and subsequent chitin accumulation, while the manure s solid stream, which primarily consisted of carbohydrates in the form of cellulose and hemicellulose, could be converted by various pretreatment methods into monosaccharides for fumaric acid production. 

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