Ethanol from cereals

Ethanol from Starchy Feedstock Ethanol from Cereal Grains... 

FIGURE 14.8 Flowchart of the commercial production of fuel ethanol from cereal grains. 

Norman, B. E., and Lutzen, N.W. 1981. Process considerations for the production of ethanol from cereals. Chapter 32 in Cereals a Renewable Resource Theory and Practice. Y. Pomeranz and L. Munck (eds.). American Association of Cereal Chemists, St. Paul, MN. 

More recently, interest has developed in the use of enzymes to catalyze the hydrolysis of cellulose to glucose (25—27). Domestic or forest product wastes can be used to produce the fermentation substrate. Whereas there has been much research on alcohol fermentation, whether from cereal grains, molasses, or wood hydrolysis, the commercial practice of this technology is primarily for the industrial alcohol and beverage alcohol industries. About 100 plants have been built for fuel ethanol from com, but only a few continue to operate (28). 

Ethanol production from cereal grains such as barley, wheat and com is a much easier process than from cellulose material. The process includes several steps, as listed below ... 

Several solvents and solvent mixtures have been used for the extraction of tocols. Hexane and a mixture of ethanol and hexane were used to extract tocols from food samples (Kramer et al., 1997 Sundl et al., 2007), acetone from microwave-oven-dried leaves (Gomez-Coronado et al., 2004), methanol from cereal grains (Michalska et al., 2007), and a mixture of methanol and chloroform from pumpkin seeds (Stevenson et al., 2007). A mixture of chloroform and methanol gave 10 20% greater amounts of tocopherols from fresh tree nuts than hexane, indicating that the mixture was more efficient than hexane... 

The use of supercritical CO2 to extract AR from cereal material was only recently presented (49). Pure supercritical CO2 was not able to extract AR even at pressures as high as 35 MPa and SS C. This result was attributed to the amphiphilic character of the AR and the non polar character of the supercritical CO2. With the addition of 10% of ethanol or methanol, it was possible to obtain extracts even at near the critical pressure (8 MPa). The optimal pressure was determined to be 3SMPa at S5°C when ethanol or methanol acted as co-solvent. The co-solvent was added as 10%wAv of the CO2. The CO2 flow was kept constant at Sg/min during the experiments. A comparison of the supercritical CO2 extraction with die addition of ethanol and classical extraction methods was made. For the classical method, pure acetone extraction at O.IMPa and 20°C was used. Between 15 and 30 MPa at 55°C, 8 to 80%w/w higher yields of AR crude extracts for the extraction with supercritical CO2 with co-solvents were obtained than for pure acetone extraction (refer to figure 2). However, the HPLC analysis of the extracts showed similar composition (49). 

In addition to its role as the primary determinant of tissue strength, a trait that is of significant interest in agriculture, cellulose constitutes the most abundant renewable energy resource on Earth. More than 200 million metric tons of stover is produced just from maize in the USA every year. About one-third of this could potentially be utilized for ethanol production (Kadam and McMillan 2003). The worldwide production of lignocellulosic wastes from cereal stover and straw is estimated to be 3 billion tons per year (Kuhad... 

To produce ethanol from starchy materials, such as cereal grains, the starch must first be converted into fermentable sugars, which are formed by starch degradation by amylases and maltases (see Section 4.5.6.1.3). For the production of beer, for example, yeast strains are selected that metabolise maltose and maltotriose (which... 

Star-branched butyl rubber, 4 437-438 copolymers, 4 445-446 Starch(es), 4 703-704, 20 452-453 as blood substitute, 4 111-112 cationic, 18 114-115 in cereal grains, 26 271-274 in cocoa shell from roasted beans, 6 357t compression effects in centrifuges, 5 513 depolymerization, 4 712 in ethanol fermentation, 10 534—535 etherified, 20 563 as a flocculant, 11 627 high-amylose, 26 288 Mark-Houwink parameters for, 20 558t modified and unmodified, 12 52-53 in paper manufacture, 18 122-123 performance criteria in cosmetic use, 7 860t... 

The first-generation biofuels can be identified as ethanol, which was produced via the alcoholic fermentation of cereals, and hio-oil or biodiesel, which was extracted from seeds such as sunflower, rapeseed, or palm. The use of cereals and sunflowers was rejected by public opinion and some scientific environments, because their use for energy production conflicted with their use as foodstuffs. In fact, the diversion of cereals to the production of ethanol for transport has led to a rise in the price of flour and derived goods, especially in Mexico. The same situation has arisen for some bio-oils, such that the source was shifted to palm-oil which, essentially, is produced in Asian countries such as Malaysia. 

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