2. LACTIC ACID (LA) IS...
Catabolic products of primary metabolism by microbes.
Also produced by many higher organism including man who
produces the acid in the muscle during work.
LA products are formed from carbohydrate fermentation that are
derived from pyruvic acid via the EMP, PP, or ED pathway
A lactic starter is a basic starter culture with widespread use in the
dairy industry.
1780 scheele identified lactic acid as the principal acid in sour milk.
3. PROPERTIES OF LACTIC ACID
Lactic acid is a three carbon organic acid:
One terminal part of an acid or carboxyl group.
Other terminal carbon atom is part of a methyl or
hydrocarbon group.
Central carbon atom having on alcohol carbon group.
Soluble in water but insoluble in other organic solvents.
Low volatility.
4. THE LACTIC ACID BACTERIA (LAB)
The are formic ates group, non-spore forming rods cocci shaped.
Carnobacterium oenococcus entrococcus pediococcus
Lactococcus paralactobacillus lactobacilus streptococcus
Lactosphaera tetragenococcus leuonostoc vagococcus.
Lacks porphyrins and cytochromes:
Do not cany out electron transport phosphorylation and hence obtain energy
by substrate level phosphorylation .
Grow anaerobically but are not killed by oxygen ( as is the case with many
anaerobes)
They obtain their energy from sugars and are found in environments where
sugar is present.
5. LACTIC ACID BACTERIA INTO MAJOR
GROUPS… .
HOMOFERMENTATIVE GROUP: produce lactic acid as the sole
products of the fermentation of sugars.
Glucose almost excluesively into lactic acid.
It convents the d-glyceraldehyde 3-phosphate to lactic acid.
Via: the embden meyerhof pathway. (I.e :glycolysis)
Only the homofermentative LAB are available for the commerical
production of lactic acid.
6. HETROFERMENTATIVE GROUP: basides lactic acid also produce
ethanol, as well as co2 uses the enzyme aldolase.
Aldolase : key enzyme in the EMP pathway and spits hexose
glucose into three –sugar –moieties.
It receive five carbon xylalose 5 phosphate from the pentose
pathway.
The five carbon xylulose is split into glyceraldehyde 3phosphate
(3-carbon) which leads to lactic acid.
And the two carbon acetyl phosphate which leads to ethanol.
7.
8. USE OF LACTIC ACID BACTERIA FOR
INDUSTRIAL PURPOSES…
The desirable characteristics of lactic acid bacteria as industrial
microorganisms include
Ability to rapidly and completely ferment cheap raw materials
Minimal requirement of nitrogenous substance.
Produces high yields of the much preferred stereo specific lactic acid.
Ability to grow under conditions of low PH and high temperature, and
Ability to Produce low amounts of cell mass as well as negliglible
amounts of other by products.
9.
10. PRODUCTION OF LACTIC ACID…
The organisms responsible for the production of lactic acid
includes.
Bacteria: lactobacillus helveticus, L salivarus, L brevis. L viridescens
L. Plantarum and pediococcus, damnosus.
Fungi: candida krusei, saccharomyces cerevisiae rhizopus sp.
It requires only a simple medium and produces L(+) lactic acid. It
also requires vigorous aeration.
Rhizopus sp: utilize glucose aerobically to produce lactic acid.
11.
12.
13.
14. Raw MATERIALS..
Cheap low levels of contaminants, rapid production rate, high yield,
little or no by-product formation, ability to be ferment with little or no
pre-treatment and year – round availability.
Starchy materials: sweet sorghum, wheat,cassava, potato, rice, rye and
barley.
These materials have to hydrolyzed into fermentable sugars before
fermentation, because they consist mainly of ( 1,4) and a(1, 6) linked
glucose.
The hydrolysis can be carried out simultaneously with fermentation.
15. CELLULOSIC MATERIALS..
These materials consist mainly of b(1, 4) glucan, and often
contain oxylan arabinan, galactan, and lignin that have
previously attempted to produce lactic acid from pure cellulose
through simultaneous saccharification and fermentation (ssf).
Some industrial waste products, such as whey and molasses, are
of interest for common substrates for lactic acid production.
16. FERMENTATION APPROACHES TO LACTIC
ACID PRODUCTION…
Batch fed-batch, repeated batch and continuous fermentations are
the most frequently used methods for lactic acid production.
Higher lactic acid concentration:obtained in batch and fed-batch
cultures.
Higher productivity:may be achieved by using of continuous cultures.
17. UPSTREAM PROCESS..
Indudes the R&D development of the strains that will be used in
the fermentation after the development of proper strain, the initial
culture ans the secondary culture were made in the flosk.
Simuttaneously the bioreactor was cleaned and avoided of
microbial contamination aseptically the nutrient media will be
prepared and from the flask culture the inoculum will be
introduced into the reactor .
At the end of the fermentation , the gude raw product will be,
collected and preserved aseptically to get the final products.
18. DOWNSTREAM PROCESS..
Will be undergone for the purification and extraction of the
compound that we need.
Extraction can be performed using the lysis method in the case of
products persists in side of the cell otherwise, the centrifugation
method only will be used to get the final products.
These above process are termed as downstream processes.
19. PROBLEMS OF LACTIC ACID BACTERIA IN
INDUSTRIES…
While using the LAB in laboratories There are several chances of
getting the contaminations and other problems
Attack by bacteriophage
Inhibition by penicillin and other antibiotics
Undesirable strains
Acid produced by the lactic starters introduce elasticity in the
curd, a property desirable in the final qualities of cheese.
20. PRODUCTION OF LA AS BY PRODUCTS..
During the production kaffir beer and other iraditional
sorghum beers lactic acid is produced as the by products.
The final product is the result of alcohol produced mainly by
s. Cerevisiae the lactic acid in the beverage is produced by
several lactobacilli.
In some palm wine, microbial malo-lactic fermentation occurs.
21. CONTINUOUS..
Mash is inoculated with lactobacilus
Agitate it maintain at 43c
After ph 5 time is added
After 24hr lactose get diminished pretreated with lime.
L.AFRM whey:
Surplus milk skim milk is used
Lactose is nutralized by heat , allowed to settle, purified.
22. USES..
Used in confectionery, fruit juices, pickles syrups.
In curing of meat, canned vege prds
Act as preservative &putrefact
Dyeing of silks &textile goods
Calcium lactate in baking powders.
Sodium lactate in moisture of tobacco
As solvents , plasticizers & modifiers, in inks.
23. REFERENCE..
Prescott, Lansing M, John p Harley, and Donald A kelin. Microbiology. Dubuque,
IA: McGraw-Hill higer education, 2005 print.
Author :AH patel
