Sugar crops

Sugar crops deliver mainly two types of sugar which can be used for industrial purposes-sucrose, a disaccharide composed by one glucose and one fructose monomer, and inulin, a polysaccharid. The latter can be obtained from topinam-bur (Hdianthus tuberosus) but is only of minor commercial importance. One example for such an application is the production of diets for diabetics [lOj. 

A by-product that accrues in both cane and beet sugar production is molasses, a syrup containing about 50% sugars. While about 47.5 kg of molasses are obtained from the processing of 1 ton of sugarcane, 32.5 kg of molasses are left from the processing of 1 ton of sugar beet This by-product is used as animal feed as well 

On the world market the benchmark future contract for both cane and beet raw sugar is called Sugar No.ll, traded at the Intercontinental Exchange (ICE) in New York. Its average price between 06/2007 and 08/2009 is estimated to have been 278 US per ton by the OECD and the EAO [14]. 

Saccharum officinarum, the sugarcane crop, is a hybrid from several Saccharum species. Through continuous breeding efforts, high yields and sugar contents could be reached. 

The stalks processed in sugar mills contain 73-76% water and 24-27% solids, of which 10-16% are soluble solids. These soluble solids in the sugar juice obtained from crushing are 70-88% sucrose, 2-4% glucose, and 2-4% fructose. 

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Alcoholic Fermentation. Certain types of starchy biomass such as com and high sugar crops are readily converted to ethanol under anaerobic fermentation conditions ia the presence of specific yeasts Saccharomyces cerevisia and other organisms (Fig. 6). However, alcohoHc fermentation of other types of biomass, such as wood and municipal wastes that contain high concentrations of cellulose, can be performed ia high yield only after the ceUulosics are converted to sugar concentrates by acid- or enzyme-catalyzed hydrolysis ... 

Energy crops Short-rotation woody crops, herbaceous woody crops, grasses, starch crops, sugar crops, forage crops, oilseed crops, switchgrass, miscanthus... 

Sugar crops Sugar cane, sugar beets, molasses, sorghum... 

Raw material for biomass fuel can come from various sources such as wood, legumes, grains, sugar crops, animal waste, municipal waste, aquatic plants, and food and cotton production waste. TABLE 12-2 provides examples of biomass raw materials. 

About 10 million gallons of the fermentation alcohol is derived from wastes such as sulfite liquor or whey, but the balance presently depends on damaged grain or sugar, crop surpluses and molasses. Relative costs of ethylene and carbohydrates will change this in a few years, but no reversal to ethanol-based ethylene is likely in this country for much longer, perhaps through 1990. ... 

It is estimated that food production would be severely disrupted if more than 15 billion gallons of com ethanol were produced. At the same time, the OECD (Organisation for Economic Co-operation and Development) estimated that replacement of 10% of America s motor fuels with biofuels would require about one third of all the cropland that is devoted to the production of cereals, oilseeds, and sugar crops. 

Lignocellulose, which comprises the main construction material of plant biomass, accounts for up to 90% of all biomass and is formed in amounts of approximately 1.5 trillion tons per year [12]. Consequently, lignocellulose is much more abundant than available amounts of vegetable oils, starch, and sugar crops. In addition to the high abundance of lignocellulose, it is inedible, and its utilization as feedstock for production of biofuels and chemicals could drastically reduce challenges of food versus fuel production. 

Agricultural, wood, and urban wastes, crop residue Wood, logging residues, trees, shrubs Starch crops such as corn, wheat, and barley, sugar crops, grasses, vegetable oils, hydrocarbon plants e.g. Pittos-porum resiniferum, Euphorbia lathyris)... 

Ulrich A. and Hills F. J. (1973) Plant analysis as an aid in fertilizing sugar crops Part 1. Sugar beets. In Soil Testing and Plant Analysis (eds. L. M. Walsh and J. D. Beaton). Soil Science Society of America, Madison, Wisconsin, pp. 271-288. 

Feedstock Options. Ethanol may be produced via fermentation (with yeast) of 6-carbon or 12-carbon sugars from a number of carbohydrate sources including sugar crops, starch crops, or lignocellulosic materials. 

Starches present in grains or root crops are readily converted to sugars for fermentation to ethanol. With the shortages of food in developing nations, grains would probably not be used for fuel. Therefore, we will consider only sugar crops and molasses to be available for ethanol production. In the initial part of the analysis, we will identify the countries where sufficient sugar is exported or molasses produced to allow production of ethanol to replace 1000 barrels of petroleum fuels. 

Although much enthusiasm currently exists for producing ethanol fuels from local sugar crops in developing nations, the results of this very cursory analysis indicate to us that at least one other option could supplement petroleum fuels used in transportation with biomass fuels at comparable or lower capital investments. This option is the use of vehicle-mounted gasifiers. 

Lipinsky, E. S., et al., Second Quarterly Report on Fuels from Sugar Crops report prepared by Battelle Memorial Institute, Columbus, Ohio for the U.S. Department of Energy, October 1977. 

Producing methanol from biomass or coal costs about twice as much as producing it from natural gas. This encourages the use of nonrenewable petrochemical sources over biomass or coal. Considering the full production cycle, methanol from biomass emits less carbon dioxide than ethanol from biomass. This is because short rotation forestry, the feedstocks of methanol, requires the use of less fertilizer and diesel tractor fuel than the agricultural starch and sugar crops which are the feedstocks of ethanol. 

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