Topic wise notes

Alcohol

1.In chemistry, an alcohol is an organic compound in which the hydroxylfunctional group (-OH) is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms.

2.An important class of alcohols is the simple acyclic alcohols, the general formula for which is CnH2n+1OH. Of those, ethanol (C2H5OH) is the type of alcohol found in alcoholic beverages, and in common speech the word alcohol refers specifically to ethanol.

3.The most commonly used alcohol is ethanol, C2H5OH, with the ethane backbone. Ethanol has been produced and consumed by humans for millennia, in the form of fermented and distilled alcoholic beverages. It is a clear flammable liquid that boils at 78.4 °C, which is used as an industrial solvent, car fuel, and raw material in the chemical industry.

4.The simplest alcohol is methanol, CH3OH, which was formerly obtained by the distillation of wood and, therefore, is called "wood alcohol". It is a clear liquid resembling ethanol in smell and properties, with a slightly lower boiling point (64.7 °C), and is used mainly as a solvent, fuel, and raw material. Unlike ethanol, methanol is extremely toxic: As little as 10 ml can cause permanent blindness by destruction of the optic nerve and 30 ml (one fluid ounce) is potentially fatal.

5.Two other alcohols whose uses are relatively widespread (though not so much as those of methanol and ethanol) are propanol and butanol. Like ethanol, they can be produced by fermentation processes. (However, the fermenting agent is a bacterium, Clostridium acetobutylicum, that feeds on cellulose, not sugars like the Saccharomycesyeast that produces ethanol.) Saccharomyces yeast are known to produce these higher alcohols at temperatures above 75 °F (24°C). These alcohols are called fusel alcohols or fusel oils in brewing and tend to have a spicy or peppery flavor. They are considered a fault in most styles of beer.

6.Simple alcohols, in particular, ethanol and methanol, possess denaturing and inert rendering properties, leading to their use as anti-microbial agents in medicine, pharmacy, and industry.

Common names

Chemical Formula / IUPAC Name / Common Name
Monohydric alcohols
CH3OH / Methanol / Wood alcohol
C2H5OH / Ethanol / Grain alcohol
C3H7OH / Isopropyl alcohol / Rubbing alcohol
C4H9OH / Butyl alcohol / Butanol
C5H11OH / Pentanol / Amyl alcohol
C16H33OH / Hexadecan-1-ol / Cetyl alcohol
Polyhydric alcohols
C2H4(OH)2 / Ethane-1,2-diol / Ethylene glycol
C3H5(OH)3 / Propane-1,2,3-triol / Glycerin
C4H6(OH)4 / Butane-1,2,3,4-tetraol / Erythritol
C5H7(OH)5 / Pentane-1,2,3,4,5-pentol / Xylitol
C6H8(OH)6 / Hexane-1,2,3,4,5,6-hexol / Mannitol, Sorbitol
C7H9(OH)7 / Heptane-1,2,3,4,5,6,7-heptol / Volemitol
Unsaturated aliphatic alcohols
C3H5OH / Prop-2-ene-1-ol / Allyl alcohol
C10H17OH / 3,7-Dimethylocta-2,6-dien-1-ol / Geraniol
C3H3OH / Prop-2-in-1-ol / Propargyl alcohol
Alicyclic alcohols
C6H6(OH)6 / Cyclohexane-1,2,3,4,5,6-hexol / Inositol
C10H19OH / 2 - (2-propyl)-5-methyl-cyclohexane-1-ol / Menthol

1.Applications

Alcohol has a long history of several uses worldwide. It is found in beverages for adults, as fuel, and also has many scientific, medical, and industrial uses. The term alcohol-free is often used to describe a product that does not contain alcohol. Some consumers of some commercially prepared products may view alcohol as an undesirable ingredient, particularly in products intended for children.

1.Alcoholic beverages

Alcoholic beverages, typically containing 5% to 40% ethanol by volume, have been produced and consumed by humans since pre-historic times.

2.Antifreeze

A 50% v/v (by volume) solution of ethylene glycol in water is commonly used as an antifreeze.

3.Antiseptics

Ethanol can be used as an antiseptic to disinfect the skin before injections are given, often along with iodine. Ethanol-based soaps are becoming common in restaurants and are convenient because they do not require drying due to the volatility of the compound. Alcohol based gels have become common as hand sanitizers.

4.Fuels

Some alcohols, mainly ethanol and methanol, can be used as an alcohol fuel. Fuel performance can be increased in forced inductioninternal combustion engines by injecting alcohol into the air intake after the turbocharger or supercharger has pressurized the air. This cools the pressurized air, providing a denser air charge, which allows for more fuel, and therefore more power.

5.Preservative

Alcohol is often used as a preservative for specimens in the fields of science and medicine.

6.Solvents

Alcohols have applications in industry and science as reagents or solvents. Because of its relatively low toxicity compared with other alcohols and ability to dissolve non-polar substances, ethanol can be used as a solvent in medical drugs, perfumes, and vegetable essences such as vanilla. In organic synthesis, alcohols serve as versatile intermediates.

Production

In industry, alcohols are produced in several ways:

  • By fermentation using glucose produced from sugar from the hydrolysis of starch, in the presence of yeast and temperature of less than 37°C to produce ethanol. For instance, such a process might proceed by the conversion of sucrose by the enzyme invertase into glucose and fructose, then the conversion of glucose by the enzyme zymase into ethanol (and carbon dioxide).
  • By direct hydration using ethylene (ethylene hydration)[8] or other alkenes from cracking of fractions of distilled crude oil.

What is Alcohol?

In chemistry, an alcohol is an organic compound in which the hydroxylfunctional group (-OH) is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms. An important class of alcohols is the simple acyclic alcohols, the general formula for which is CnH2n+1OH. The most commonly used alcohol is ethanol (C2H5OH) is the type of alcohol found in alcoholic beverages, and in common speech the word alcohol refers specifically to ethanol. Ethanol has been produced and consumed by humans for millennia, in the form of fermented and distilled alcoholic beverages. The simplest alcohol is methanol, CH3OH, which was formerly obtained by the distillation of wood and, therefore, is called "wood alcohol". It is a clear liquid resembling ethanol in smell and properties, with a slightly lower boiling point (64.7 °C), and is used mainly as a solvent, fuel, and raw material. Two other alcohols whose uses are relatively widespread (though not so much as those of methanol and ethanol) are propanol and butanol. Like ethanol, they can be produced by fermentation processes. (However, the fermenting agent is a bacterium, Clostridium acetobutylicum, that feeds on cellulose, not sugars like the Saccharomycesyeast that produces ethanol.) Saccharomyces yeast are known to produce these higher alcohols at temperatures above 75 °F (24°C). These alcohols are called fusel alcohols or fusel oils in brewing and tend to have a spicy or peppery flavor. They are considered a fault in most styles of beer.

Microorganisms Used in Alcohol Production

There is a limited number of microorganisms which ferment carbohydrates (pentose or hexose sugars) into alcohols and yield some by-products. Microorganisms utilize various pathways. A summary of alcohol production through different routes of microorganisms is given. Following are some of alcohol producing micro-organisms:

  1. Bacteria: Clostridium acetobutylicum, Klebsiellapneumoniae, Leuconostocmesenteroides, Sarcinaventriculi, Zymomonasmobilis, etc.
  2. Fungi: Aspergillusoryzae, Endomyceslactis, Kloeckerasp., Kluyreromyeesfragilis, Mucorsp., Neurosporacrassa, Rhizopussp., Saccharomycesbeticus, S. cerevisiae, S. elltpsoideus, S. oviformis, S. saki,Torulasp., Trichosporiumcutaneum, etc.

Production of alcohols by microorganism 1-Lactobacillus brevis; 2-Leuconostoc mesenteroides.

Ethanol Formation by Bacteria

  1. Sarcinaventriculi

Sarcinaventriculiform ethanol through fructose-1:6-bisphosphate pathway i.e. EMP pathway and pyruvatedecarboxylase as formed by yeasts.

  1. Zymomonasmobilis

A rod shaped polarly flagellated and motile bacterium (Zymomonasmobilis) is known to metabolize glucose through the Entner-Doudoroff pathway and results in pyruvic acid. Pyruvic acid is then decarboxylysed by pyruvatedecarboxylase to acetaldehyde and carbon dioxide. Acetaldehyde is reduced to ethanol. Thus, the fermentation products are ethanol, carbon dioxide (and small amount of lactic acid). In some members of Enterobacteriaceae and Clostridia, ethanol is formed as a subsidiary product. Acetaldehyde is not directly produced from pyruvic acid by pyruvatedecarboxylase, but originates through reduction of acetyl CoA.

  1. Leuconostocmesenteroides

Lactobacilli (e.g. Leuconostocmesenteroides) use quite different pathway for alcohol production. In the beginning of fermentation they utilize pentose cycle to result in xylulose-5-phosphate, which is then cleaved by phosphoketolase into acetyl phosphate and glyceraldehyde-3-phosphate. Acetaldehyde dehydrogenase and alcohol dehydrogenase reduce the acetylphosphate into ethanol. Similarly, glyceraldehyde-3-phosphate is converted via pyruvic acid to lactic acid (Schlegel, 1986).

  1. Clostridium acetobutylicum

Clostridium acetobutylicum, ATCC 824, is a commercially valuable bacterium sometimes called the "Weizmann Organism", after Jewish-Russian born Chain Weizmann, then senior lecturer at the University of Manchester, England, used them in 1916 as a bio-chemical tool to produce at the same time, jointly, acetone, ethanol, and butanol from starch. The method was described since as the ABE process, (Acetone Butanol Ethanol fermentation process), yielding 3 parts of acetone, 6 of butanol and 1 of ethanol, reducing the former difficulties to make cordite, an explosive, from acetone and paving the way also, for instance, to obtain vehicle fuels and synthetic rubber

  1. Ethanol Formation by Yeasts

Yeasts, especially strain of S. cerevisiaeare the main producer of ethanol. They have been used as a major biological tool for the formation of ethanol since the discovery of fermentation process by the time of L. Pasteur. During 1890s fermentation of froth was discovered in sugar solution on addition of yeast extracts obtained by its grinding. This was the first evidence for a biochemcial process of in vitro formation of ethanol in the absence of yeast cells. The extract supplied inorganic phosphate (Pi) which is incorporated in fructose-l:6-bisphosphate. Fructose- l:6-bisphosphate is accumulated due to lack of ATP utilization for energy requiring reactions in the cell free systems. Therefore, an excess of ATP is maintained. The reaction is given below:

2C6H12O6+pi=2C2H5OH +2CO2+2H2O+fructose-1:6-bisphosphate

This equation is known as Harden - Young equation after the name of the discoverer. Energetic of EMP pathway reveals that one molecule of glucose yields only 2 molecules of

ATP from 2 molecules of ADP under anaerobic condition in contrast of 38 molecules of ATP

Through respiration:

C6Hl2O6 + 2Pi + 2ADP =2C2H5OH+2Co2+2H2O+2ATP + energy.

.

Outline of alcohol production by yeast cells

  1. Neurosporacrassa

Two strains of Neurosporacrassa have been identified which utilize cellulase and produce extracellular cellulase [see 1, 4-(1,3; 1,4)-β-d-glucan 4-glucanohydrolase, EC 3.2.1.4] and β-d-glucosidase [β-d-glucosideglucohydrolase, EC 3.2.1.21]. The activities were detected as early as 48 h in the culture broth. These cultures also fermented d-glucose, d-xylose and cellulosic materials to ethanol as the major product of fermentation. The conversion of cellulose to ethanol was >60%, indicating the potential of using Neurospora for the direct conversion of cellulose to ethanol.

  1. SACCHAROMYCES CEREVISIAE

Saccharomycescerevisiae is in the fungi kingdom. The reasons for this classification are because it has a cell wall made of chitin, it has no peptiodglycan in its cell walls, and its lipids are ester linked. It also uses DNA template for protein synthesis and it has larger ribosomes. It is then consider yeast because it is a unicellular organism so it can not form a fruiting body; like other fungi.

Importance: Saccharomycescerevisiaeis one of the most important fungi in the history of the world. This yeast is responsible for the production of ethanol in alcoholic drinks and is the reasons your mother’s bread dough rises in the pan. That is where the names brewer’s and baker’s yeast come from. The process in which it produces ethanol is one way this yeast converts glucose into energy. There are two ways Saccharomycescerevisiaebreaks down glucose. One way is through aerobic respiration. This process requires the presence of oxygen. When oxygen is not present the yeast will then go through anaerobic fermentation. The net result of this is two ATP, and it also produces two by products; carbon dioxide and ethanol. So if this yeast is allowed to grow in a container lacking oxygen it will produce ethanol (alcohol). Humans have been isolating this process since the beginning of history. The yeast helps in the rising of bread with its other by-product carbon dioxide. The gas that is produce inside the dough causes it to rise and expand. Both of these processes use the haploid of this yeast for this process. In industry they isolate one strain, either a or ά, of the haploid to keep them from undergoing mating. (Madigan, 457) In the baker’s yeast they have a strain were the production of carbon dioxide is more prevalent then ethanol and vice versa for brewing. (Tomvolkfungi.net) Another importance is that “live yeast supplementation to early lactating dairy goats significantly increased milk production”.

“Grain handling: a critical aspect of distillery operation”

  1. Introduction

Until recently, sanitation in grain handling has been basically ignored by the distilling industry,except for those engaged in beverage alcohol production. We are forced to realize that a good sanitation program and procedures are essential to the bottom line. Outbreaks of food animal diseases such as BSE (Bovine spongiform encephalopathy) and food-borne diseases such salmonella, as wellas prohibitions against mycotoxins and insecticides in grains going into food animals and ultimately the human food chain, have grabbed our attention. We suddenly realize thatdistillers dried grains with solubles (DDGS) is a valuable co-product and not just an unavoidablenuisance. Also, if we cannot sell it because of contamination, we are out of business.

We first became aware of the importance of a sanitation program in grain handling systems some years ago in the brewing industry. Breweries by definition prepare a food product,

beer, and are subject to all possible scrutiny by the Food and Drug Administration (FDA) and

related state and local food safety bureaus. Breweries routinely underwent very involved inspections for food contamination and looked forward to them with much dread. In the 1970s,

a group of federal inspectors appeared at one plant and after providing the proper credentials

and the warrants necessary for the inspection, surprised the staff by asking only for a sample of brewer’s spent grains. The staff relaxed and gladly obtained a sample of spent grains under the inspectors’ directions. Two weeks later the plant was upset with a notice of citation for improper sanitation procedures since insect fragments, mold, mycotoxins and insecticide residuals were found in those spent grains. Since animal feed laws were less stringent in the 1970s than today, the plant was allowed to continue selling the spent grains. The agency just used the contamination detected as a means of bringing attention to an inadequate sanitation program as established forbreweries under the Federal Food, Drug and Cosmetic Act.

  1. FORMS OF CONTAMINANTS, DETECTION AND REMOVAL

First, it is important to be aware of the different forms of contamination that may be present in

the raw materials brought in for processing. Second, everything possible must be done toensure detection of such contamination before it enters the facility. And, third, everythingpossible must be done to avoid, remove or destroy the contaminants before using these rawmaterials. These three are very closely related.

What kind of contaminants can we expect? Among others, insects, rodents and birds andtheir droppings, stone, cobs, weed seeds, glass, wood, rags, tramp metal, residual insecticides and fumigants, water, bacteria, mold and mycotoxins. Some of these are from unclean grain handling and transport. Others have been added as fillers, adding weight without

producing usable substrate. Some, like stone and tramp metal, are dangerous and may cause fires

and explosions in the grain handling system. The more difficult contaminants to detect such as

residual insecticides and fumigants as well as mycotoxins, can be present at levels that can

result in unmarketable DDGS.

Bushel weight, moisture, damaged kernel and broken kernel/foreign material tests are run immediately. High insect infestation may be determined by visual inspection, but low

infestations may be more difficult to find. Also, the true grain weevils, because they bore into

kernels, may not be visible on the surface of the grain. Only a few plants use a black light to

detectaflatoxin presence. Black light is also usable for the detection of rodent urine contamination. This should be a routine test for all shipments in all plants. NIR technology offers

a solution to many of the grain testing needs for quick decision making by distillers.

Do not neglect the senses. Examine the grain, checking for insect presence, rodent droppings, bird feathers as well as foreign seeds and extraneous matter such as cobs, straw, wood and metal. Smell the material for any hint of mold presence or chemical contamination. Feel the

grain for moisture and slime presence.

A recent discussion with a group of farmers supplying corn to some of the newest

fuel ethanol plants coming on stream was very revealing concerning the state of the corn market

in some areas of the country. The farmers were quite happy that the new distillers were paying

the same price for No. 2, 3, 4 and 5 grain as they are for No. 1. This seems not only wasteful

on the part of the distiller, but potentially dangerous. The more allowable extraneous content in the lower grade incoming grain, the greater the contribution to lower yields and the higher likelihood of gross contamination and possible ignition of fires and explosions.

High moisture is the most common reason for rejection of a shipment. This is a good start. High moisture contributes to difficulties in milling and handling and to lower yields. High moisture also contributes to elevated mold growth, which typically leads to contamination with mycotoxins that become concentrated in the DDGS.

First, decide on specifications for acceptance of the incoming substrate. Next, provide the people and the testing equipment to determine if the substrate meets those specifications. Stick to the established specifications. Only when satisfied should you begin to unload the material into the plant’s infrastructure.

  1. RECEIPT AND STORAGE

Specifications should call for all shipments to be received in covered hopper railroad cars andhopper trucks fully covered by tarpaulin or someother means. This will help prevent appearanceof rodents and other pests while the shipment isin transit.

Once the shipment is accepted, it can thenproceed to the unloading area. Most people drop