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INDUSTRIAL BIOTECHNOLOGY

ASSIGNMENT-LACTIC ACIDBY

KAVITA JHA ROLL.NO:0911PGDMBT003

PGDM-BIOTECHNOLOGYINSTITUTE OF PUBLIC ENTERPRISE

LACTIC ACIDUnlike the name suggests, lactic acid is not derived from milk. Lactic acid is the acid ingredient of sour dairy products, fermented fruits and vegetables and sausages. Lactic acid has been consumed by humans since prehistoric times.

Lactic acid as a product of nature, however, is even older. It is present in every form of organized life and was supposedly already prevalent in the first forms of primitive life that existed on earth. Many bacterial species produce lactic acid, with Lactobacillus, Bifidobacterium, Streptococcus, Pediococcus and Leuconostoc being the predominant examples.

Lactic acid found in animals and humans has many functions, the most important of which is related to the supply of energy in muscle tissue. Metabolic turnover of lactic acid in adult men has been estimated to be approximately 120 to 150 g per day.

HISTORY OF LACTIC ACIDLactic acid was discovered in 1780 by Swedish chemist, Carl Wilhelm Scheele, who isolated the lactic acid from sour milk as impure brown syrup and gave it a name based on its origins: 'Mjölksyra'. The French scientist Frémy produced lactic acid by fermentation and this gave rise to industrial production in 1881.Lactic acid is produced by the fermentation of sugar and water or by chemical process and is commercially usually sold as a liquid.

Pure and anhydrous racemic lactic acid is a white crystalline solid with a low melting point. Lactic acid has two optical forms, L(+) and D(-) . L(+)-lactic acid is the biological isomer as it is naturally present in the human body.

LACTIC ACID STEREO ISOMERS

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LACTIC ACID IN THE HUMAN BODYLactic acid is naturally present in humans, as well as in animals. It is well known that it is formed from glycogen by muscle cells when the oxygen supply is inadequate to support energy production.

There are many misconceptions about Lactic Acid and Lactate in the body. Lactate was long considered one of the causes of both fatigues during exercise and the stiffness felt after. However, on the contrary, lactate is actually an important fuel used by the muscles during prolonged exercise, since lactate produced in one muscle can be oxidized in another muscle. So, rather than causing fatigue, lactic acid and lactate help delay the onset of fatigue and improve sport performance.

LACTATE AND EXERCISE Lactate has often been considered one of the major causes of both fatigue during exercise and post-exercise muscle soreness. However, lactate may have little effect on either. Moreover, it may help to improve performance.

Accumulation of lactic acid (generated from the anaerobic breakdown of glycogen), in the muscle, occurs only during short bouts of exercise of relatively high intensity and it is usually related to fatigue and muscle soreness. However, because lactate is so rapidly removed from muscle and blood after exercise, it is highly unlikely that lactate is the cause of any resulting muscle soreness. It may be that the accumulation of H+ ions during glycolisis contributes to fatigue during short-term maxim exercise. Oral lactate may postpone fatigue, by increasing buffer capacity of the body and reducing acidosis, in turn delaying fatigue.

On the other hand, it is believed that during endurance-type exercise, the depletion of muscle glycogen causes fatigue. In such conditions, lactate may serve as an energy source. It has been observed that the lactate produced in one muscle can be oxidized within another muscle. Due to its insulin independence, lactate could prove to be a more readily available energy substrate.

Better performance is often related to lactate clearance from the blood. The increase in blood lactate levels during exercise is reduced by acclimatization. Therefore training and lactate supplementation may help to increase lactate clearance and subsequently improve performance.

HOW IS LACTIC ACID PRODUCED? Lactic acid can be produced naturally or synthetically. Commercial lactic acid is produced naturally by fermentation of carbohydrates such as glucose, sucrose, or lactose. The current world market leader in the commercial production of lactic acid is PURAC: www.purac.com.

The natural production process is shown in the figure below. Wih the addition of lime or chalk, the raw materials are fermented in a fermenter and crude calcium lactate is formed. The gypsum

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is separated from the crude calcium lactate, which results in crude lactic acid. The crude lactic acid is purified and concentrated and L(+) lactic acid is the result.

LACTIC ACID PRODUCTION PROCESS

USES OF LACTIC ACID(i) It is used as an acidulant in fruit juices, confectionery and essences.

(ii) Derivative of lactic acid such as calcium lactate and iron lactate are used in the treatment of calcium deficiency and anemia respectively.

(iii) Sodium lactate is used to help retension of moisture by such products as tobacco and as a platicizer.

(iv) Lactic acid production from whey also helps removal of pollution of our environment because untreated whey disposed off in our waterways would cause dangerous consequences. It is so because whey is very high in Biological Oxygen Demand (BOD).

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PHYSICAL PROPERTIES OF LACTIC ACID

Chemical Abstracts Registration CAS.-Reg.-No. [79-33-4]Chemical formula C3H6O3

Chemical name (S)-2-hydroxy-propanoic acidMolecular Weight 90.08Physical appearance aqueous solutionTaste mild acid tasteMelting point 53oC / 127oFBoiling point > 200oC / 390oFSolubility in water (g/100 g H2O) miscibleDissociation Constant, Ka 1.38 * 10^ -4pKa 3.86pH (0.1% solution, 25oC) 2.9pH (0.1 N solution, 25oC) 2.4

L (+) lactic acid

ECONOMICS OF LACTIC ACIDThe economics of lactic acid production is influenced to a large extent by:

Raw material costs, Acid productivity in batch or continuous operations, And the product concentration.

APPLICATIONS OF LACTIC ACID

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Lactic acid has received a significant amount of attention as a chemical with many potential applications. There are four major categories for the current uses and applications of lactic acid: food, cosmetic, pharmaceutical, and chemical applications.

APPLICATION IN PHARMACEUTICALS L (+) Lactic acid is used in pharmaceutical industry as a  very important ingredient in IV Fluids. Lactated Ringers solution and Sodium Lactate are used in IV Fluid therapy. They provide the energy and volume for blood besides regulation of pH.

Calcium , Sodium , Ferrous and other salts of lactic acid are used in the pharmaceutical industry in various formulation.

Lactate salts have better absorption, solubility and are easily metabolized resulting in administration of some very important drugs like ciprofloxacin as a lactate salt.

Lactic acid based formulations find use for their anti tumor activity.

The anti microbial action of lactic acid is taken advantage for use as sanitizers.

It is reported that lactic acid finds use in the treatment of dermatological problems like warts.

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APPLICATION IN COSMETICSNatural L (+) Lactic acid is used in many applications in cosmetics. Lactic acid is an alpha hydroxy acid ( AHA ) and is found in the skin. It is used as a skin rejuvenating agent, pH regulator. It is a common ingredient in  Moisturizers, Skin whiteners, anti acne preparations, etc.

Since L(+)-lactic acid is naturally present in the skin, Lactic acid and Sodium lactate are extensively used as moisturizing agents in many skin care products. Lactic acid is also used as a pH-regulator. It is one of the most effective AHAs and has the lowest irritation potential. Lactates are regarded as skin whitening agents that have been shown to produce a synergistic effect when combined with other skin whitening agents.

Sodium Lactate is used in anti perspirant preparations. L(+)-lactic acid is used as a pH-regulator in many types of hair care formulations.

APPLICATION IN FOOD INDUSTRYLactic acid occurs naturally in many food products. It has been in use as an acidulant, peservative and pH regulator for quite some time. Some of the important applications of lactic acid in the food industry are detailed below. There are many  properties of lactic acid which make it a very versatile ingredient in the food industry. It has a pronounced preservative action, and it regulates the microflora.It has been found to very effective against certain type of micro organisms. Sometimes a combination of lactic acid and acetic acid is used as it has a greater bactericidal activity. Because it occurs naturally in many food stuffs, it does not introduce a foreign element into the food.The salts are very soluble, and this gives the possibility of partially replacing the acid in buffering systems.Lactic acid is non-toxic and is deemed "Generally Recognized As Safe" (GRAS)  as a general purpose food additive in the USA. The same status is accorded in many other countries too. The calcium salt of lactic acid, calcium lactate, has greater solubility than the corresponding salt of citric acid . In  such products where turbidity caused by calcium salts is a problem, the use of lactic acid gives products which are clear. L (+) Lactic acid is the natural lactic acid found in biological systems and hence its use as an  acidulant does not introduce a foreign element into the body.

CONFECTIONERY

Lactic acid finds use as an acidulant in the confectionery industry. It is a better acidulant than citric acid since the sugar inversion is less when used for hard boiled candies. It does not have the initial burst of flavour and tanginess of citric acid. Lactic acid imparts a more mellow and lasting souness. It enhances the flavour much more. The use of buffered lactic acid in continuous production lines for high boiled sweets is more recent application. Liquid buffered lactic acid can be easily measured into the molten syrups, even at the high temperatures used in depositing lines.Sugar inversion will be minimal. 

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 BEER AND WINE

Lactic acid is a natural beer acid, and hence it  is used for pH adjustments during the mashing process and in  wort cooking. Lactic acid improves the microbial stability and also enhances the flavour. Almost all the breweries in India use the L (+) Lactic acid manufactured by Lactochem Limited.

BEVERAGES

Lactic acid due to its mild nature is the acidulant of choice in delicately flavoured soft drinks and fruit juices. It does not mask   or over power the natural flavour. Its flavour enhancing property makes the beverage more palatable and leaves a lingering taste. Lactic acid is preferred over citric acid for these reasons.

OLIVES, PICKLES, CABBAGE, GHERKINS

Green olives, Gherkins and others  are often packed in a solution of salt, lactic acid and water. The lactic acid acts as a preservative and improves  the clarity of the brine and flavour. A mixture  of acetic acid and lactic acid in pickled products such as gherkins, silver skin onion etc imparts a milder taste and flavour, and improves microbial stability. Large quantity of gherkins in brine with Lactochems’s L (+) Lactic acid is exported from India to many countries world wide. Calcium  lactate is reported to be used as firming salt, which have been used for canned fruits and vegetables.

DAIRY PRODUCTS

Direct acidification with lactic acid, in dairy products such as cottage cheese, is preferred to fermentation as the risks of failure and contamination can be avoided. The processing time also can be saved. Lactic acid  and calcium lactate are used extensively in the production of Channa and Panneer by direct acidification. Lactic acid is also used as an acidulant in dairy products like cheese and yogurt powder.

BAKERY PRODUCTS

For direct acidification of certain breads, lactic acid is the natural sour dough acid. The general appearance of a loaf of bread is greatly improved by the use of bacterial lactic acid, a larger loaf results per weight of bread with improved bloom, and color of crust. Lactic acid is directly added to certain types of fermented dough crispy biscuits. 

Lactic acid added to dough increases the shelf life due to its retarding action on molds and rope.The sodium and calcium stearoyl lactyllates find use as emulsifiers in the baking indistry as they provide substantial quality improvement of baked products besides reducing shortening levels.

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 MEAT AND MEAT PRODUCTS

Lactic acid is widely used in meat products as an anti microbial agent. Decontamination of beef, poultry and pork carcasses in slaughter house operations is practised to reduce Salmonella infection. In sausages, sodium lactate is used  to reduce water activity and achieve higher  shelf-life. Recent research publication, indicates the use of hot lactic acid spray on carcasses where reduction of over 99 % of E.Coli has been observed. 

INDUSTRIALAPPLICATIONS Poly (lactic acid) or Lactic acid polymers are environmentally compatible because they degrade into natural, harmless products. The polymers degrade primarily by hydrolysis after exposure to moisture. These polymers find use in the pharmaceutical industry in dental, surgical implants, drug delivery systems and other applications.

Lactic acid has better descaling properties than conventional organic descalers due to which reason it is used in many decalcification applications such as cleaners for toilets, bathrooms etc. Lactates find use as neutralizers in the production of certain type of surfactants used in special detergents and personal care products.

Lactate esters like ethyl, methyl lactate etc are used for degreasing since they have excellent action for oils, oligomeric and polymeric stains.  Lactic acid is used in Ni-plating processes because of its unique complexing constant for Ni. It acts as a pH buffer and stabilizer for the bath.

Lactic acid is used as a pH regulator and complexing agent in various binder systems for water-based coatings such as electro deposition coatings.

LACTIC ACID MARKETLactic acid is used to impart flavor as well as in the preservation of some foods. It is also used in production of acid fermented foods. Lactic acid is produced commercially for use in pharmaceuticals and foods, in leather tanning and textile dyeing and in making plastics, solvents, inks and lacquers. Lactic acid is mainly an import product. As can be seen from the table the supply of lactic acid for the last eight years was on average 3.37 tonnes annually.

Year Import 1999 1.50 2000 0.70 2001 16.90 2002 0.45 2003 0.30 2004 1.35 2005 2.30 2006 3.44

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As an import product the supply of lactic acid is assumed to grow at least by 10% annually. Thus the current effective demand for the product is estimated based on 2004-2006 average annual import at a growth rate of 10% and is estimated to be 3 tonnes.

The demand for lactic acid is a raw material for the pharmaceuticals, leather, textile and plastics sector is determined by the demand and supply of products under these industries. The demand projection is, therefore, made based on GDP growth rate of 8.7%.

PROJECTED DEMAND FOR LACTIC ACID (TONNES)

Year Projected Demand

2008 3.3 2009 3.5 2010 3.6 2011 4.2 2012 4.6 2013 4.9 2014 5.4 2015 5.8 2016 6.4 2017 6.9

CONCLUSIONSThe current major markets for lactic acid are food- -related industries, but the emerging markets for PLA polymer would cause a significant increase in growth of lactic acid consumption Currently, the worldwide consumption of lactic acid is estimated to be 130 000–150 000 (metric) tonnes per year, and the commercial prices of food grade lactic acid range between 1.38 US$/kg (for 50 % purity) and 1.54 US$/kg (for 88 % purity). Technical grade lactic acid with 88 % purity has been priced as much as 1.59 US$/kg. Lactic acid consumption in chemical applications, which include PLA polymer and new green solvents, such as ethyl lactate, is expected to expand 19 % per year.

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