Sucrose as feedstock

Examples of a successful effort to utilize sucrose as feedstock for the manufacture of bulk organic chemicals are the announcements of several companies of the production of bioethylene from sugar via bioethanol. Based on such green ethylene, Crystalsev and Dow Chemicals are planning to start the production of... 

In total the planned bioethylene production capacity seems low compared to the annual ethylene production of 100 million tons (2000) but it is enough to show the capability of utilizing sucrose as feedstock for organic chemicals. The door towards the whole C2-chemistry being based on renewable resources is opened. 

Transportation costs of imported s. are confronted with the expense of moving 2-3 mt s. for 1 mt of yield. A novel important drawback is in the costly waste disposal because of environmental problems. Exchange of s. for sucrose as feedstock for large-scale fermentation may become significant in the... 

Sucrose acrylate derivatives can be converted into polymers and hydrogels that can be used as flocculants, water adsorbents, bioimplantables, and dmg dehvery devices (42). Sucrose ethers have appHcations as surfactants and surface coatings, and as feedstocks for synthesis of polyurethane foams and... 

The above chemicals can be obtained by fermentation (qv) of other sugars. However, some compounds require sucrose as a unique feedstock. Examples are the polysaccharides dextran, alteman, andlevan, which are produced by specific strains of bacteria (48,54—56). Dextrans are used to make chromatographic separation media, and sulfated dextran derivatives are used as plasma extenders (41). Levans show promise as sweetness potentiators and, along with alteman, have potential as food thickeners and bulking agents in reduced-caloric foods (55,56) (see Carbohydrates). 

In a broad sense, fermentation can be defined by all chemical transformations brought about by living microorganisms, starting with carbohydrates and some N, P, S and other nutritients as feedstock. World-wide use of carbohydrates for fermentation is about 30 million tons/year, of which 20 million is sucrose, the remainder glucose, lactose and starch. 

Currently, in the first generation of bioethanol, food crops such as com, sugar cane, and wheat are used for the production of energy. These are starch- or sucrose-rich feedstocks that are readily fermented by microorganisms. However, these crops are also used for food and feed production, resulting in competition. At present, commercial production of the first-generation biomass utilizes readily-available sugars from these food plants for the fermentation process of biofuel production. 

Feedstock for Chemical Synthesis. It is estimated that <0.5% of the sucrose produced each year is used for nonfood purposes (41). An alternative appHcation, namely the production of chemicals, is an attractive option as the feedstock is plentiful, renewable, and of consistently high purity. Moreover, the biodegradabiUty of many sucrochemicals makes them environmentally friendly. 

Fermentation Feedstock. Sucrose, in the form of beet or cane molasses, is a fermentation feedstock for production of a variety of organic compounds, including lactic, glutamic, and citric acids, glycerol, and some antibiotics. Lesser amounts of itaconic, aconitic, and kojic acids, as well as acetone and butanol, are also produced (41,51—53). Rum is made by fermentation of cane molasses. Beet and cane molasses are used for production of baker s and brewer s yeast (qv). 

A more abundantiy produced substance is ethanol for use in alcohoHc beverages, and as a fuel, solvent, and feedstock for organic syntheses. Ethanol (qv) production from sucrose is carried out in Europe (eg, France and the Netherlands), India, Pakistan, China, and on a very large scale in Brazil, where it is used as a motor fuel. A valuable by-product of ethanol fermentation is industrial CO2 (see Carbon dioxide). 

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