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J. Environ. Res. Develop.Journal of Environmental Research And Development Vol. 7 No. 1A, July-September 2012
234
*Author for correspondence
ISOLATION, IDENTIFICATION AND CHARACTERIZATION
OF LACTIC ACID BACTERIA FROM
DAIRY SLUDGE SAMPLE
Choksi Nikita and Desai Hemangi*
TIFAC-CORE In Environmental Engineering, Sarvajanik College of Engineering and Technology
Surat, Gujarat (INDIA)
Received May 02, 2012 Accepted September 10, 2012
ABSTRACT
Lactic Acid Bacteria (LAB) commonly used as starter cultures in food technology are known to
manufacture antimicrobial products having great potential. The aim of this study is isolation of lactic
acid bacterial strain which has been potential for lactic acid production, to identify, characterize it and
to optimize culture conditions for the process. For this study, we have isolated different strains of Lactic Acid Bacteria (LAB) from dairy sludge samples which were collected from 3 different dairy
plant of Gujarat, (India). Therefore, characterization of isolated strains through morphological,
physiological, biochemical and carbohydrate fermentation test were done. Lactic Acid Bacteria (LAB)
are a group of Gram-positive, non- spore forming, cocci or rod shaped, catalase-negative and fastidious
organisms, considered as ‘Generally Recognized As Safe’ (GRAS) organism. For isolation, samples
were serially diluted and plated on MRS agar (DE MAN, ROGOSA and SHARPE agar. HI Media)
Plate. Well-isolated colonies with typical characteristics were picked from each plate and were further
sub cultured until pure isolates were obtained and transferred to MRS broth (HI Media) for further
experiments. Identification of lactic acid bacteria belongs to family Lactobacillaceae was done first
at genus level in the Lactobacil lus, Lactococcus, Streptococcus, Leuconostoc, Pediococcus.
Lactobacillus is rod shape and Streptococcus, Leuconostoc, Pediococcus are cocci shape. Most of
them are used in dairy starter culture, present in raw milk, milk-loving bacteria. Isolated colony was
identified by gram-staining, gram +ve and rod shape strain showed confirmation of lactobacillus . L.bulgaricus and Streptococcus thermophilus were found as the most dominant species in common
sludge unit. While L.acidophillus was found as dominant species along with the L.bulgaricus and
Streptococcus thermophilus in the sludge of pro biotic acidophilus butter milk manufacturing unit
and L.casei, L.helveticus, L.brevis, L.lactis were present as the dominant species in the cheese
manufacturing unit along with the L.bulgaricus and Streptococcus thermophilus. Selected microbial
isolates obtained in this study will be used for production of lactic acid acts as monomer for the
synthesis of biodegradable polymer on my future study.
Key Words : Lactic Acid Bacteria (LAB), Isolation, Dairy sludge, MRS agar plate,
MRS Broth, Bacterial strain
INTRODUCTIONTo overcome the problem of environmental
pollution through outcome of industries, waste and
pollutant from different industries, unused packing
material and one is the possible solution of these
problems is to minimize the use or to enhance the
reutilization of waste material. But simplest way
to minimize the rate of pollution is by
manufacturing article from biodegradable material.Biodegradable material are those which can be
degrade in the presence of environmental
condition like soil, moisture, microorganism, light,
heat etc. and end products of this is not harmful
to environment.
Dairy industry produces huge volumes of wastes,
both solid and liquids. This waste poses escalating
disposal and pollution (High BOD) problems and
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J. Environ. Res. Develop.Journal of Environmental Research And Development Vol. 7 No. 1A, July-September 2012
represents a loss of valuable biomass and
nutrients. However, despite their pollution and
hazard aspects, in many cases, dairy processing
wastes have a good potential of converting into
useful products of higher value as by-product, or
even as raw material for other industries. Organic
acids are examples of such valuable by-productof the fermentation of high carbohydrate
containing industrial substrates. They therefore
could be utilized cheaply as substrate for
microorganisms producing intermediate volume
high value organic acids like lactic acid. Lactic
acid is under increasing demand in food,
pharmaceutical and chemical industries and for
production of polylactic acid polymers, which
possess outstanding biomedical applications.
Wastes generated from dairy plants may be
regarded as a viable option for meeting this
growing demand for lactic acid and lactic acidhas received attention for use if a wide range of
applications mostly as it acts as a monomer for
the production of biodegradable poly (lactic acid)
or polylactide (PLA). PLA can be produced
chemically and biotechnologically but
biotechnologica l routes are mostly favored
because of environmental concerns and limited
nature of petrochemical feedbacks. Worldwide
efforts have been made for the production of lactic acid and PLA with good yield and low costmanagement.1,2
A long history record of lactic acid used infermentation, preservation of food stuffs is alsoavailable. Lactic acid was firstly discovered byScheela in, 1780 in sour milk and named byLavoisier is acid lactique in 1789 which becamethe origin of present terminology lactic acid.3 Lacticacid has been approved by the US FDA as GRAS
(Generally Recognized As Safe) for the
consumption of it as a food additive, cosmetic,
pharmaceutical, medical implantation4 It can be
produced by chemically and biotechnologically
both.5,6 But due to several serious problems, its
biotechnology route is more favorable because
racemic DL-lactic acid is produced by chemical
synthesis from petro chemical sources whereas
an optically pure L(+) or D(-) lactic acid can be
obtained by microbial fermentation of renewable
sources and higher physical properties of
polymerized Poly Lactic Acid (PLA) is crucially
dependent on the optically pure L(+) or D(-) lactic
acid which is suitable for commercial products.7,8
For the pilot scale production of lactic acid though
biotechnological route, there have been various
requirement for high productivity i.e. cheap raw
material , lactic acid producing microorganism,
fermentation approach, type of bioreactor andfinally purification of optically pure lactic acid for
production of high crystalline lactic acid.
So that production of PLA can be divided into
two step i.e. production of lactic acid and its
polymerization to PLA. Here, initially required
lactic acid producing bacteria which help to lactic
acid production with easily available raw material.
Lactic acid bacteria are a group of related bacteria
that produce lactic acid as a result of carbohydrate
fermentation. The concept of the group name
Lactic Acid Bacteria’ was created for bacteriacausing fermentation and coagulation of milk and
defines as those which produce lactic acid from
lactose. The family name Lactobacteriaceae
was applied by Orla-Jensen to a physiological
group of bacteria producing lactic acid alone or
acetic and lactic acids, alcohol and carbon dioxide.
Today, lactic acid bacteria are regarded as
synonymous by and large with the family
Lactobacteriaceae.
Lactic acid bacteria are widely distributed in the
nature. They could be isolated from soils, waters, plants, silages, waste products and also from the
intestinal tract of animals and humans (Axelsson).
Lactic Acid Bacteria (LAB) are characterized
as Gram - positive, usually non-motile, non -
sporulating bacteria that produce lactic acid as a
major or sole product of fermentative metabolism.
Kandler and Weiss have classified Lactobacillus
isolates from temperate regions according to their
morphology, physiology and molecular characters9
Schleifer classified LAB based on the molecular
characteristics10 LAB from food and their current
taxonomical status have been described by many11,12
These microbes are broadly used by us in the
production of fermented food products, such as
yogurt (Streptococcus spp. and Lactobacillus
spp.), cheese ( Lactococcus spp.), Sauerkraut
( Leuconost oc spp.) and sausage. These
organisms are heterotrophic and usually have
complex nutritional necessities because they lack
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J. Environ. Res. Develop.Journal of Environmental Research And Development Vol. 7 No. 1A, July-September 2012
236
many biosynthetic capabilities. Most species have
multiple requirements of amino acids and vitamins.
Because of this, lactic acid bacteria are generally
abundant only in communities where these
requirements can be provided. They are often
associated with animal oral cavities and intestines;
plant leaves as well as decaying plants or animalmatter, compost, etc.
The classification of lactic acid bacteria into
different genera is largely based on morphology,
mode of glucose fermentation, growth at different
temperatures and configuration of the lactic acid
pr oduced ability to grow at high sa lt
concentrations and acid or alkaline tolerance.
Lactic acid bacteria are among the best studied
microorganisms for human health advantageous
effects and fermentation. Significant novel
developments have been made in the research of lactic acid bacteria in the area of multidrug
resistance, bacteriocins, osmoregulation, autolysins
and bacteriophages. Advancement has also been
made in the production of food grade genetically
modified lactic acid bacteria.
In the previous studies, LAB could be isolated
from many kinds of sources such as milk products,
sugar cane plants13, fresh water fishes14, but
studies on isolation of LAB from dairy sludge
sample remain scare. Therefore, dairy isolates of
lactic acid bacteria capable of degrading dairy
waste as well as working with other waste raw
material and converting them into lactic acid are
considered to be the key to the development of a
workable microbial fermentation based value
addition process for dairy wastes containing lactic
acid bacteria.
MATERIAL AND METHODS
The present study used sludge samples collected
from 3 different well known dairy plants in Gujarat
at India. Sludge sample collected inside ice box
and transferred to the laboratory for
microbiological analysis MRS agar and broth were
used for enumeration and culture of LAB.15 The
sludge samples serially diluted and pour plated on
MRS plates. The MRS plates overlaid with MRS
agar and incubated at 37 °C for 48–72 h. This is
optimal temperature for bacterial growth but
different lactobacillus strains isolated at particular
temperature set up here for colony isolation and
incubated at 300C, 370C , 400C, 420C and 500C
for 48-72 hours. Well - isolated colonies with
typical characteristics with entire margins were
picked from each plate and transferred to MRS
broth. Lactobacilli isolated on MRS agar should
be further confirmed biochemically.
Identification of lactic acid bacteria at thegenus level
For identification of lactic acid bacteria, overnight
cultures of each isolate in MRS broth were used.
All isolates were initially tested for gram reaction,
catalase enzyme and production of acid from
glucose in Hugh and Leifson medium by oxidation
or fermentation rection (Harrigan and
MacCance). Only gram positive bacteria with
catalase negative reactions were observed
(Schillinger and Lucke, Garvie and Weiss.) and
the representative isolates were purified bysuccessive streaking on to the same agar
substrate. For the gram-positive, catalase negative
rods, growth at various temperature 100C, 150C
and 450C ,tolerance of different salt levels (2,4
and 6.5% w/v NaCl), hetero- and homo-
fermentative activity (using MRS broth) with
inverted Durham tubes in MRS broth were
determined. Isolates from dairy sludge were then
selected based on the above tests for further
identification. The bacteria were characterized by
microscopic and by conventional biochemical and
physiological test. The culture were examined for
colony and cell morphology, motility, gram stain
and production of acid from glucose (Harrigan
and MacCance. In addition to the oxidation and
fermentation test according to Hugh and Leifson.
These preliminary test make it possible to classify
the isolates in genus on the basis of characteristic
and tests of identification mentioned by Harrigan
and MacCane, Hammes et al., Holzapfel and
Schillinger and Dicks et al.
Identification of lactic acid bacteria to the
species level
After their microscopic examination , gram +ve
and catalase –ve lactobacillus were tested for
their sugar fermentation pattern, production of
ammonia from arginine in addition to their ability
of growth at 150C and 450 C. according to
Harrigan and Maccance.16
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J. Environ. Res. Develop.Journal of Environmental Research And Development Vol. 7 No. 1A, July-September 2012
RESULTS AND DISCUSSION
Isolation and identification
Colonies of lactic acid bacteria were observed
on the surface of MRS plates. More than one
colony was observed in most of the cases.
Cultural and morphological characteristics wereexamined with the help of microscope. Different
types of microorganisms were observed, majority
of them belonged to Gram+ve rods and cocci
shaped bacteria. The purification of isolates was
done by transferring Gram+ve rods and cocci
shaped bacteria to the plates of selective media
MRS respectively. These isolates were further
sub cultured until pure isolates were obtained.
Numbers of lactic acid bacterial cultures were
isolated from dairy sludge samples. After initial
identification, most of them were determined as
representative of the family Lactobacillaceae
and genus Lactobacillus and rest were referred
to genus Lact ococcu s, Streptococ cus,
Pedi ococcus, Leuconostoc and some of
Bi fidobacteria, Staphylococcus etc.17,18 A
summary of micro-organisms associated withmilk and milk products is given in Table 1.
This genus should be possible in sludge sample is
depend on many factors like dairy industries
region, raw milk sample, starter culture used for
production, production unit working such as crude
manufacturing, paneer manufacturing, different
types of cheese manufacturing, probiotic butter
milk, seasonal changes, temperature, weather
effects, drainage system etc. So, all time we could
not get same genus as well as same species
Section (According to 9th Family Genus
edition of Bergey’s Manual)
Bacteria Spirillaceae Campylobacter
Pseudomonadaceae Pseudomonas
Brucella
Neisseriaceae Acinetobacter
Moraxella-like organisms
Enterobacteriaceae Escherichia
Enterobacter
Salmonalla,Yersinia
Vibrionaceae AeromonasChromobacterium
Flavobacterium
Vibrio
Rickettsiaceae Coxiella
Microccaceae Micrococcus
Staphylococcus
Streptococcaceae Steptococcus
Leuconostoc
Bacillaceae Bacillus
Clostridium
Lactobacillaceae Lactobacillus
Listeria Propionibacteriaceae Propionibacterium
Corynebacteriaceae Corynebacterium
Arthrobacter
Microbacterium
Actinomycetaceae Actinomyces
Mycobacteriaceae Mycobacterium
Nocardiaceae Nocardia
Table 1 : Micro-organisms associated with milk and milk products
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therefore, probability changes based on condition.
Here, we are interested to isolate lactic acid
bacteria which are potential for lactic acid
production in nutrient agar more of this were
isolated with it fungal and mould also grown and
contamination problem occurs. So MRS agar is
selected for study. Colonies were identifiedaccording to their morphological, cultural,
physiological and biochemical characteristics 10,11.
This all genus grown on agar plate is used in dairy
starter culture and some of it was present in raw
milk also. Further, genus lactobacillus was
studied on subgenus and species level by
biochemical test as well as some part icular
identification characteristics.
Although LAB are comprised of 11 genera,
only 6 of them are dairy associated
These are Lactococcus, Enterococcus, Streptococcus,
Leuconostoc, Pediococcus, and Lac tobacillus .
(Axelsson, Garvie) Identification test for the
same is shown in Fig. 1.
Pediococcus is a genus of gram-positive lacticacid bacteria, placed within the family of
Lactobacillaceae. They usually occur in pairs
or tetrads and they are purely homofermentative.
Pediococci are used as probiotics, and are
commonly added as beneficial microbes in the
creation of cheeses and yogurts. Recently, lactose
positive pediococci have been used instead of
Streptococcus thermophilus. Lactococcus is a
s
Gram Positive, catalase -negative
Gas from glucose
–v e
Cocci Rods Lac toball ius
homofermentative
Tetrad
Growth @15°C
+Ve pedioc occ us
–Ve
Growth@
45°C
–Ve +Ve
Growth@10°C
+Ve
Lac tococc us
–Ve
Lac toc occ us
+Ve
Enterococcus
Growth 6.5 NoCI
–Ve
thermobacterium
+Ve
treptobacterium
+ve
–v e
Cocci
leuconostorsRoads
Lac tobaci llu Roads
heterotementative
Fig. 1 : Route for identification of lactic acid bacteria at genus levelgenus of Gram-positive lactic acid bacteria that
were formerly included in the genus Streptococcus
Group N1. They are catalase-negative, non-motile
cocci that are found singly, in pairs, or in chains
and they are homofermentors. These organisms
are commonly used in the dairy industry in the
manufacture of fermented dairy products like
cheeses. They can be used in single-strain starter
cultures, or in mixed-strain cultures with other
lactic acid bacteria such as Lactobacillus and
Streptococcus. The bacteria also play a role in
the flavor of the final product.
Steptococcus is a genus of gram- positive lactic
acid bacteria. They are catalase-negative-cocci
usually found in chains or pairs. Some of species
are also great value as they used by dairy industry
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J. Environ. Res. Develop.Journal of Environmental Research And Development Vol. 7 No. 1A, July-September 2012
for the manufacturing of fermented dairy
products.
Leuconostoc is a genus of gram-positive bacteria,
placed within the family of Leuconostocaceae.
They are generally avoid cocci in pairs or often
forming chains. Leuconostoc spp. are catalase-
negative (which distinguishes them fromStaphylococci). All species within this genus are
heterofermentative, i.e., glucose is fermented with
production of D(-) lactic acid, ethanol and CO2
and are able to produce dextran from sucrose.
They are generally slime-forming and used in
cheese manufacturing.
Lactobacillius are gram-positive rods, typically
non-motile, non-sporulating and non-acid fast,
lactobacilli are aerobic and facultatively
anaerobic, catalase negative and grow best at PH
6.0. the carbohydrates and polyalcohols are
changed by homofermentation to lactic acid or by heterofermentation to lactic acid and acetic
acid, alcohols and carbon dioxide. The genus was
subdivided by Orla-jensen into three groups
(Thermo bacterium, Strepto bacterium and beta
bacterium).
Identification test of Lactobacillus bacteria
All isolates were microscopically examined for
gram stain reaction, cell morphology and cellular
arrangement (Gerhardt et al., and Sneath et al.
Catalase test
A drop of 3% hydrogen peroxide was placed on
a clean microscopic slide. With a nicrome wire
loop pick up cells from the center of a well isolated
colony of the test culture and transfer them into
the drop of hydrogen peroxide. Both were mixed
and observed for gas bubble production. The
strains showing gram-positive and catalase
negative isolates were identified at species level.
Physiological and biochemical identification
Each isolate was activated in 5 ml MRS broth for
24 h at 30 ºC before use. Therefore, overnightcultures were used during all the identification
procedures. Physiological and biochemical
identifications were performed according to the
methods and criteria of Sharpe and Fryer; Garvie,
Devriese et. al., Teuber.
For the identification of rod shaped isolates,
following tests were applied
1. Gas poduction from glucose
2. Growth at different temperatures (15ºC, 45ºC)
3. Growth at 6.5% NaCl concentration
4. Arginine hydrolysis5. Carbohydrate fermentation
Gas production from Glucose
In order to further define ho mofermentative
isolates, CO2 production from glucose test was performed. For this purpose, MRS broths and
inverted Durham tubes were used. 50µl of
overnight cultures were transferred into the 8 ml
test media. After incubation for 5 days at 30 ºC,
gas accumulation in Durham tubes was taken as
the evidence for CO2 production from glucose.
Voges-Proskauer (V-P) Test
Inoculate the medium Glucose Phosphate Broth
(GPB) with culture and incubate the medium at
370 C for 24-48 hours. After incubation, add 0.6
ml of a- naphthol and 0.2 ml of KOH solution per ml of broth.(Reagents should be added in this
order only because a-naphthol exerts catalytic
effect only if added before the KOH). Shake well
after addition of each reagent and slope the tube
to increase the aeration. Development of pink-
red color within 15 minutes or more, it means V-
P positive for particular species so, we could
concluded this lactobacillus strain either
thermobacterium or streptobacterium and V-P
negative identified betabacterium.
Growth at different temperatures
50µl of overnight cultures were transferred into
the tubes which contain 5 ml temperature test
media. After inoculation, they were incubated for
7 days at 10 ºC, 40 ºC or 45 ºC. Cells growth at
any of these temperatures was detected by the
change in the color of the cultures, from purple to
yellow.
Growth at different NaCl concentrations
50µl of overnight cultures were transferred into
the tubes which contain 5 ml NaCl test media.
Isolates were tested for growth at 2%, 4% or
6.5% NaCl concentrations. They were incubated
for 7 days at 30ºC. The change of the color from
purple to yellow taken as the evidence for cell
growth.
Arginine hydrolysis test
The arginine hydrolysis, arginine MRS broth was
used instead of Reddy broth. 50µl overnight
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cultures were inoculated into 5 ml arginine test
media, and were then incubated for 5 days at 30ºC.
After the incubation, ammonia production was
detected by using Nessler reagent. For this
purpose, 100 µl of culture broth were pipetted into
each well of the microtitre plates and 100 µl of
Nessler reagent were added. Immediate orangecolor formation was taken as the indication for
ammonia production. No color change indicated
that the strain could not hydrolyse arginine.
Identification of Cocci
The characteristic used for the identification of
cocci shaped LAB in this study were presented.
Except for the arginine test, all the other tests
were the same as those for bacilli shaped LAB.
Arginine hydrolysis and gas production from
citrate
In order to perform this test, 8 ml of Reddy broth
and inverted Durham tubes were used. Fifty µl of
overnight cultures were inoculated into the Reddy
broth and were then incubated for 5 days at 30ºC.
Arginine hydrolysis
The cultures which utilize arginine, change the
color of the broth first to yellow due to the lactic
acid production and to violet because of the
ammonia production (Cardinal et al). On the other
hand, the cultures which do not utilize arginine
assume a deep-yellow color by producing lactic
acid only.Gas production from citrate
The breakdown of the citrate results in production
of carbon dioxide. Gas accumulation in inverted
Durham tubes indicated citrate utilization.
Sugar fermentation tests
Carbohydrates differentiation discs (from Hi-
media) was used for sugar fermentation test.
Andrade peptone water, liquid media are
dispensed in 5 ml amount in test tube with
inverted Durham’s tube for testing fermentation
and sterilized. A single carbohydrate disc is added
to each tube aseptically and inoculated with test
organisms.
Incubation is carried out at 36±1.0º C for 18-48
hours and results are recorded at 18-24 hours and
again at 48 hours. The results should be frequently
observed since reversal of fermentation can take
place. In case of liquid medium gas produced
during fermentation is collected in the inverted
Durham’s tube while acid production changes color
of the medium. In case of fermentation, the color
of sugar was changed from red to yellow,
reflecting the test as positive.
Percentage distribution of different genus of lactic
acid bacteria were collected from 3 different dairy
industries A, B, C. Dairy sludgeA1(common
sludge unit), Dairy sludgeA2 (acidophilus
but termilk production unit ). dairy sludgeB1(common sludge unit), dairy sludgeB2(cheese
manufacturing unit),dairy sludgeC1(common
sludge unit), dairy sludgeC2(cheese manufacturing
unit). Differential characteristics of lactic acid
bacteria based on morphology and physiology
determined from various microbial and analytical
confirmation test is shown in rod shape
Lactobacillus is divided into three groups.
Summary of Differential characters of
lactobacillus is shown in Table 2. Rod shape
lactobacillus is divided into three groups.
Summary of Differential characters of lactobacillus is shown in Table 3.
The best available microscopic results of the
experiments are shown in Fig. 2 to Fig.4.
Morphological and simple physiological
Characterization of LAB which were isolated from
the dairy sludge sample based on microscopic
characterization and analytical test is shown in
Table 5.
Results of sugar fermentation test and growth
stability at various temperature based on chemical
test is shown inTable 2.
Fig. 2 : Lactic acid
bacteria colony
Fig. 3 : Streptococcu
thremophilus
Fig. 4 : Lactobacillus
bulgaricus
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J. Environ. Res. Develop.Journal of Environmental Research And Development Vol. 7 No. 1A, July-September 2012
Sample Lactic acid bacteria (%)
Streptococcus Leuconostoc Lactococcus Pediococcus Lactobacillus
Dairy SludgeA1 40 5 10 - 45(common Sludge unit)
Dairy SludgeA2 (acidophilus 15 - 5 - 50
buttermilk production unit)
Dairy Sludge B1 35 5 5 5 50
(common sludge unit)
Dairy Sludge B2 30 5 10 - 55
(cheese manufacturing unit)
Dairy Sludge C1 35 10 5 5 45
(common sludge unit)
Dairy Sludge C2 25 5 10 5 55
(Cheese manufacturing unit)
Characteristics
Morphology Cocci Cocci Cocci cocci in tetrads Rods
CO2 from glucose* - - - - ±
Growth
10°C - + + ± ±
45°C ± - - ± ±
6.5% NaCl - - - ± ±
pH 4.4 - ± ± + ±
pH 9.6 - - - - -
Lactic acid configuration L L L L, DL D, L, DL
Table 3 : The percentage distribution of different genus of LAB in dairy sludge sample
and differential characteristics of lactic acid bacteria based on morphology
+Positive; -negative; varies between pecies
*test for homo- or hetero fermentation of glucose : -homofermentation, + heterofermentation
Test Thermo bacterium Strepto bacterium Beta bacterium
Motility – – –
Growth at 5ºc – – –
Growth at 15ºc – + V
Growth at 45ºc + + ?
Gas from glucose – – +
Voges- Proskaucer reaction + + –
Nitrate reduction – – –
Fermentation Homofermentation Homofermentation Heterofermentation
Table 3 : Differential characters of the three group of Lactobacillus
+ = Positive reaction; – = Negative reaction; V= Variable reaction
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T a b l e 4 : M
o r p h o l o g i c a l a n d s i m p l e p h y s i o l o g i c a l c h a r a c t e r i z a t i o n o f L A B
i s o l a t e d f r o m
t h e d a i r y s l u d g e s a m p l e
S p e c i e s
C e l l s h a p e
G r a m
C a t a l a s e
A c i d
A c i d
C o 2
C e l l u l a r
O p t i m u m
s t a i n
a c t i v i t y
f r o m
f r o m
f r o m
a r r a n g e m e n t
t e m p e r a t u r e
r e a c t i o n
g l u c o s e
l a c t o s e
g l u
c o s e
L .
b u l g a r i c u s
R o d s
G + v e
-
+
+
-
s i n g l e , p a i r s a n d s h o r t c h a i n
s
4 0 ° C
L . a c i d o p h i l u s
R o d s
G + v e
-
+
+
-
s i n g l e , p a i r s a n d s h o r t c h a i n
s
3 5 - 3 8 ° C
L . c a s e i
R o d s
G + v e
-
-
+
-
S h o r t o r l o n g c h a i n r o d s .
3 0 ° C
L .
l a c t i s
R o d s
G + v e
-
-
+
-
L o n g , s i n g l e o r i n p a i r s
4 0 ° - 4 3 ° C
L .
h e l v i t i c u s
R o d s
G + v e
-
+
+
-
s i n g l e , p a i r s a n d s h o r t c h a i n
s
4 0 0 - 4 2 ° C
L .
b r e v i s
R o d s
G + v e
-
+
V
+
S i n g l e o r i n c h a i n .
3 0 ° C
t h e r m o p h i l l u s
C o c c i
G + v e
-
+
+
+
P a i r o r l o n g c h a i n C o c c i
4 0 º - 5 0 ° C
L a c t o b a c i l l u s s p p .
R o d s
G + v e
-
±
±
±
S h o r t o r l o n g c h a i n r o d s
3 0 º - 5 0 ° C
S t r e p t o c o c c u s
s p p .
C o c c i
G + v e
-
±
±
±
S p h e r i c a l a n d o v o i d s h a p e
3 0 º - 3 7 ° C
C o c c i
L e u c o n o s t o c s p p .
C o c c i
G + v e
-
±
±
±
P a i r o r s h o r t c h a i n c o c c i
1 5 º - 3 5 ° C
P e d i o c o c c u s s p p .
C o c c i
G + v e
-
±
±
±
T e t r a d s i n p a i r o r s h o r t c h a i n
2 5 ° - 3 2 ° C
C o c c i
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T a b l e 5
: R e s u l t s o f s u g a r f e r m e n t a t i o n t e s t
G r o w t h a t
S u g a r f e r m e n t a t i o n
S / N
L a c t i c a c i d
M o r
p h o
5 ° C
1 5 ° C
4 5 ° C
A c i d a n d
N H 3
A r a b i
M a n n
M e i z i M
e l i b
R a f f i
S o r b i
T r e h a
M a l
L a c t
G a l a
l o g y
g a s f r o m
f r o m
n o s e
i t o l
t o s e i
o s e
n o s e
t o l
l o s e
t o s e
o s e
c t o s e
g l u c o s e
a r g i n i n e
1
L . b u l g a r i c u s
R
-
-
+
-
-
-
-
-
-
-
-
-
v
+
+
2
L . a c i d o p h i l u s
R
-
-
+
-
-
-
+
-
v
+
-
+
+
+
+
3
L . c a s e i
R
-
+
V
-
-
-
+
+
-
-
+
+
+
+
+
4
L . l a c t i s
R
-
-
+
-
-
-
+
-
-
+
-
+
+
+
+
5
L . h e l v e t i c u s
R
-
-
+
-
-
-
-
-
-
-
-
-
+
+
+
6
L . b r e v i s
R
-
+
-
+
+
+
-
-
+
v
-
-
v
v
v
7
S .
t h e r m o p h i l u s
C
-
+
V
-
+
+
-
v
v
v
v
v
+
+
+
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CONCLUSION
Sludge samples were collected from 3 different
dairy plants. Identification of lactic acid bacteria
belongs to family Lactobacillaceae was done
first at genus level in the Lact obac il lus ,
Lactococcus, Streptococcus, Leuconos toc,
Pediococcus. Lactobacillus is rod shape andStreptococcus, Leuconostoc, Pediococcus are
cocci shape. Most of them are used in dairy starter
culture, present in raw milk, milk-loving bacteria.
Isolated colony was identified by gram-staining,
gram +ve and rod shape strain showed
confirmation of Lactobacillus . L.bulgaricus and
Streptococcus thermophilus were found as the
most dominant species in common sludge unit.
While L.acidophillus was found as dominant
species along with the L. bu lgar ic us and
Streptococcus thermophilus in the sludge of pro biotic acidophilus butter milk manufacturing unit
and L.casei, L.helveticus, L.brevis, L.lactis were
present as the dominant species in the cheese
manufacturing unit along with the L.bulgaricus
and Streptococcus thermophilus.
RECOMMENDATION
This species can be used in further study for
production of lact ic acid from natural waste
resources.
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