References 1
Ackerson, M. D. 1991 , 16th IGT Conf Energy from Biomass and Wastes, Washington, DC, 725. Adt, R. R., Rhee, K. T. 1978 , U. S. Department of Energy, Report No. eY-76-5-05-5216, 8 pp. Agu, R. C, Amadife, A. E, Ude, C. M 1997 , Waste-Management. 17 1 , 91-96. Aiba, S., Shoda, M. 1969 , Ferment. Technol. 47,790. Aiba, S., Schoda, M., Natatani, M. 1968 , Biotechnol. Bioeng. 10,845. Alcon Biotechnology Ltd. 1980 , 20 Eastbourne Terrace, London. Anonymous 1978 , Chem. Eng. News 56 32 , 22. Anonymous...
Mashing Processes Mashing Equipment Wet Cleaning of Potatoes
Before processing potatoes, they must be cleaned and free from sand, stones, soil, and potato foliage. For this purpose washing rolls with a minimum length of about 3 m and a minimum diameter of 1.5 m are used. The potatoes pass 0 1 2 3 4 5 6 24 48 72 96 Stillage Fermentation Time h Fig. 9. Saccharification of triticale mash using the enzyme combination OPTIMALT . Yeast added after 30 min of saccharification distillation after 96 h of fermentation. through the turning wash roll with...
Processing Grain
If HPCP is used for processing grain it is important to load enough water into the Henze cooker before starting the steaming process. Normally, therefore, about 300 L water are used per 100 kg of grain of any variety. The required amount of water is pumped into the Henze cooker, and the steaming valve at the bottom is opened a litte to suspend the grain. Then the grain is loaded into the Henze cooker and after closing, the bottom steaming valve is opened. The grain has to be evenly distributed...
Corn
Processing corn for ethanol production is influenced by the high temperature needed for gelatinization of corn starch and the presence of varying amounts of horny endosperm in the corn. The horny endosperm of corn is elastic. This leads to problems in milling since milled corn remains gritty, even if a 1.5 mm screen is used. The use of smaller screens is not recommended due to the fat content of corn, which leads to very small throughputs in milling or to clogging of screens. Gritty particles...
Manioc
Manioc is a tropical plant, forming starch-containing roots. Since manioc roots do not keep well, they should be processed immediately or, alternatively manioc starch can be produced from dried roots. It is also possible to mill the roots and to dry the obtained manioc flour. Average analyses of different manioc products are given in Tab. 12. Tab. 11. Average Analysis of Sorghum Grain Tab. 11. Average Analysis of Sorghum Grain Tab. 12. Average Analysis of Manioc Products Tab. 12. Average...
SemiContinuous Processes
The semi-continuous processes Yarovenko, 1978 comprise the so-called outflow-inflow and overflow processes and also a wide range of battery and cyclic fermentation variants. In semi-continuous processes a portion of the culture is withdrawn at intervals and fresh medium is added to the system. Repeated fed-batch culture, which can be maintained indefinitely, is another name of the semi-continuous process. Characteristic of these processes is the continuous feed liquid flow after addition of a...
Processing Tropical Raw Materials Sweet Sorghum
Sweet sorghum is a raw material containing fermentable sugars. Since it does not keep well after harvest, it cannot be imported from tropical countries. There have been some attempts to grow sweet sorghum in Austria and Germany Diedrich et al., 1993 Salzbrunn, 1982 . To obtain ethanol from sweet sorghum it is first necessary to produce a sugar juice from the plant stems. This can be done in two ways The first possibility is water extraction with a countercur-rent extraction plant the second way...
Processing Potatoes 1
Potatoes used in alcohol production should be in good condition and free from plant diseases. This is a problem, since industrial potatoes are harvested only from September until the end of October, and it is impossible to process all the harvested potatoes in that time. Therefore, it is necessary to store potatoes before processing, for which special store houses are in use. They must be fitted with aeration and washing channels. In one of these store houses with, e.g., a length of 31 m and a...
References
Adam, W., Bartels, W., Christoph, N., Stempfl, W. 1995 , Brennereianalytik, Vol. 1-2. Hamburg Behr's Verlag. Aufhammer, W., Pieper, H. J., St tzel, H., Sch fer, V. 1993 , Eignung von Korngut verschiedener Getreidearten zur Bioethanolproduktion in Abh ngigkeit von der Sorte und den Aufwuchsbedingungen, Bodenkultur 44,183-194. Aufhammer, W., Pieper, H. J., K bler, E., Sch fer, V. 1994 , Eignung des Korngutes von Weizen und Triticale f r die Bioethanolproduktion in Abh ngigkeit vom...
Fusel Oils
Fusel oils are formed from a-keto acids, derived from or leading to amino acids. The overall composition is found to be an isomeric mixture of primary methyl butanols and methyl propanols, the majority of which is isoamyl alcohol Maiorella et al. et al., 1981 . Tab. 26 compares the composition of fusel oils from different sources. Yields of up to 20 L may be attained per m3 of ethanol generated using standard sugar sources, however, this value depends upon the pH in the fermenter. Fusel oils...
Genetically Modified Organisms
Future progress in ethanol tolerance and the range of possible substrates used in these fermentation systems may be enhanced through genetic recombination techniques. Although a multitude of strain variations from these yeasts have been produced through genetic manipulations, due to their prokaryotic nature, manipulation of the genetic material in bacterial species is carried out with greater ease than in yeasts. Today, through genetic engineering one can obtain more versatile bacteria that can...
Rectification of Product Spirit from Raw Spirit
Rectification of raw spirit, when distilleries produce their own potable spirit, is normally carried out using a batch rectifying apparatus. These rectifying stills are manufactured completely from copper. Only the pipes collecting the top fraction of the heads are from stainless steel to avoid corrosion of copper. These rectification stills Fig. 22 in principle consist of Fig. 22. Batch rectifying apparatus Kreipe, 1981 . Fig. 22. Batch rectifying apparatus Kreipe, 1981 . - a receiver for the...
Stillage 1
Stillage consists of the non-volatile fraction of material remaining after alcohol distillation. The composition of this effluent varies as a function of location and the type of feedstock used to produce it. The characteristics of stillage arising from representative crops are shown in Tab. 25. In general, these slops consist of less than 10 solids of which 90 is protein from the feedstock and spent microbial cells. The remainder is made up of residual sugars, residual ethanol, waxes, fats,...
Enzymatic Starch Liquefaction and Saccharification
Malt is the classical source of amylolytical enzymes used in alcohol production technology. It contains both liquefying and saccharifying enzymes. The amylolytical components of malt are - 3-amylase -1,4-glucan maltohydrolase, EC 3.2.1.2 , As reported by Sargeant and Walker 1977 , -amylase from malt can hydro-lyze native starch granules. jS-Amylase is an exo-acting enzyme and hydrolyzes starch yielding maltose. Starch molecules are attacked from the non-reducing end of the glucose chains....
Enzymatic Starch Liquefaction
Technical liquefying enzymes are virtuallyall a-amylases a-l,4-glucane4-glu-canohydrol-ase, E.C. 3.2.1.1 that split a-1,4 bonds in amylose and amylopec-tin. a-Amylase is an endo-acting enzyme and its action is often considered to be random, i.e., the enzyme has equal preference for all a-1,4 linkages except those adjacent to the ends of the substrate chain and those in the vicinity of branch points. The a-1,6 glycosidic bonds are not hydrolyzed.The properties as well as the action of a-amylase...
Processing Wheat
It is possible to process wheat with an AAQ of 95 or higher without the addition of enzymes. It is necessary to grind the material thoroughly or to use a hammer mill fitted with a 4 mm screen, combined with further use of the dispersing mash process. In either case, water and or stillage is pumped into the mash tub, and after adjusting the pH to between 5.2 and 5.5, wheat is ground in the hammer mill and pumped into the mash tub BAB is then added as liquefying enzyme. The mash temperature in...
Modifications and Conversions of Existing Internal Combustion Engines to
The utility of alcohols as substitute fuel for the internal combustion engine has been under investigation for some time. As early as 1897, Nikolaus A. Otto used pure ethanol in his first engine Rothman, 1983 . In the 1920s and 1930s in Germany, Switzerland, and in the U.S., fuel ethanol was used extensively. Both, beneficial and detrimental characteristics of ethanol as a motor fuel have long been noted and widely recognized. The General Motors Research Laboratories in Warren, Michigan, have...
Analysis of Raw Materials Starch Content of Potatoes
In practice it is very difficult to determine the exact starch content of potatoes, since it is virtually impossible to prepare an average sample under practical conditions. Furthermore, the starch content varies among individual potatoes. Special balances are used to determine the density of potatoes. In this procedure exactly 5,050 g of wet potatoes are weighed out, and then these potatoes are weighed again under water. The density of potatoes can be calculated using Eq. 2 The relation...
Enzymatic Starch Saccharification
Glucoamylase EC 3.2.1.3 is an exo-acting enzyme, hydrolyzing a-1,4 a-1,6, and a-1,3 glycosidic linkages in amylose and amylopectin. The rates of hydrolysis depend on the molecular size and structure of the substrates Fogarty and Kelly, 1979 .Thus glucoamylase from Aspergillus niger, e.g., hydrolyzes isomaltose at a lesser rate than maltose These authors show, that branched substrates are hardly degraded by glucoamylases derived from several fungi. This may be a problem in alcohol production...
Rye Eln
The processing of rye is affected by the content of pentosans. A high content of pentosans leads to high viscosities in mashes which become evident at the beginning of the process, when ground rye is solubilized in water. These high viscosities persist during the mashing process and the fermentation. This problem can be solved by using pentosanases, which are rather expensive, or by running a certain mashing program Quadt, 1994 Ingledew et al., 1999 Wang et al., 1997 . If pentosanases are...
Yeast Fermentation
The fermentation of sugar to ethanol by yeast has an important place among the different processes that are used in industry. The yeasts, which are of primary interest to industrial operations are Saccharomyces cerevisiae, Saccharo-myces uvarum carlsbergensis , Schizosaccharomyces pombe, and Kluyvero-myces species. The optimum conversion of sugar to ethanol requires a yeast strain capable of tolerating high ethanol concentrations, since ethanol inhibits growth and fermentation, although the...
Introduction 1
The environmental problems caused by the continued and increasing use of fossil feedstocks as energy source and the fact that the supply of many of their more desirable embodiments is approaching exhaustion are two main problems associated with the utilization of fossil fuels. Fermentative production of chemicals and energy production from renewable resources have been seriously considered as an alternative to petrochemical processes in recent years. Probably the best known of the alcohols...
Info
Fig. 4. Pathways for the formation of products of the mixed acid and 2,3-butanediol fermentations Rosenberg, 1980 though all of the strains of this bacterium can use glucose, only 50 of them can convert sucrose to glucose. The usage of sucrose causes excessive quantities of unwanted by-products during the fermentation and this is a disadvantage of Z. mobilis. The strong production of organic acids e.g., acetic acid, lactic acid which cause problems during the rectification of the ethanol is...
Thermophilic Organisms
The selected strains normally operate best at pH 4.5 and 28-30 C, with efficiency dropping off rapidly at higher temperatures Keim, 1983 . However, the substrate must be cooled since the fermentation is exothermic. The advantages of using thermophilic microbes in the production of fuel alcohol are numerous. Since ethanol-producing yeasts growing at an optimal fermentation temperature of 50 C have to be discovered yet, it is apparent that thermophilic bacteria Tab. 4 are necessary for these...
Fermentation Modes of Industrial Interest
Ethanol can be produced by applying mainly four types of operations in industry batch, continuous, fed-batch and semi-continuous. Batch and continuous production of ethanol are more widely used. Cell recycle may advantageously be used with any of these operations, but the substrate must be essentially free of insoluble materials which could accumulate with the cell during centrifugation and build up to unacceptable amounts in the system. For example, sugar juices, molasses, and clear starch...
Distillation and Rectification of the Alcohol Product from Mashes
Because of the energy consumption in distillation and rectification, it is necessary to use a continuous and combined distillation and rectification still in large-scale plants for ethanol production. Kreipe 1981 and Kirschbaum 1969 have reported details for such plants. Investment in such plants is too expensive, and their capacities are too high for distilleries working in the classical tradition. In 1993, a distillation and rectification still was developed that may be of interest to...
Ethanol Fermentation with Bacteria
A great number of bacteria are capable of ethanol formation Buchanan and Gibbons, 1974 . Many of these microorganisms, however, generate multiple end products in addition to ethyl alcohol. These include other alcohols buta-nol, isopropyl alcohol, 2,3-butanediol , organic acids acetic, butyric, formic, and lactic acid , polyols arabitol, glycerol, and xylitol , ketones acetone , or various gases methane, carbon dioxide, hydrogen .The microorganisms which are capable of producing ethanol as the...