Nutritional Requirements of Microorganisms
Nutritional
Requirement
by
Microorganisms
Nutrients
are
substances used in biosynthesis and
energy release
and
therefore
are
required
for
microbial
growth
INTRODUCTION
Common
Nutrient
Requirements
The
first
six (C,
O,
H,
N, S and
P)
:
components of
carbohydrates,
lipids
and
proteins
K
+
: enzyme
-protein
synthesis
Ca
2
+
:
heat resistance
of
bacterial
endospores
Mg
2+
:
cofactors,
stabilise
the cell
membrane
and
ribosomes
Fe
2+
and
Fe
3+
:
part of
cytochrome
and
cofactors for
enzymes
and
ECP
95%
cells
dry
weight
Carbon
Oxygen
Nit
r
og
e
n
P
h
osp
h
o
r
o
u
s
Calcium
Hyd
r
og
e
n
P
otassium
Mag
n
esium
Sulphur
I
r
on
Mac
r
oeleme
n
t
s
/
Macronutrients
Micronutrients/
Trace
elements
:
Several
nutrients
which
are required
in small
amounts
Ubiquitous
and
normally part of
enzymes and
cofactors
Aid
in
catalysis
of reaction
and
maintenance
of
protein
structure
Mn
2+
:
transfer
of
phosphate
groups
Mo
2+
:
nitrogen
fixation
Co
2+
:
component
of vitamin
B
12
Hence
microorganisms require
a balanced mixture of
nutrients
Micro
nutri
ents
Man
g
a
n
ese
Zi
n
c
Cobalt
Molybdenum
Nickel
Co
p
p
er
Requirements
for
Carbon,
Hydrogen, Oxygen
and
Electrons
All
o
r
g
ani
s
ms
ne
e
d
c
arbon,
o
x
yg
en,
h
y
d
r
o
g
en
and
s
ou
r
ce
of
electrons
CARBON
:
Skeleton/backbone
of
all
organic
molecules
from
which
the
organism
is
built
HYDROGEN
&
OXYGEN
:
Important
elements
found
in
the
organic
molecules
ELECTRONS
Electron
transport
chain
and
the
oxidation
reduction
reactions-
o
r
g
anic
energy
for
use
in cellular
work
Reduce molecules during
biosynthesis
(CO
2
molecules)
re
d
uced
AUTOTROPHS
:
use only
CO
2
as a
sole
source
of
carbon
obtain
energy
from
light or reduced
inorganic
molecule
Because
CO
2
cannot supply
their
energy
needs, they
must obtain
energy
from
other
sources,
such
as
light
or reduced
inorganic
molecules
HETEROTROPHS
:
organisms
that
use reduced,
preformed organic
molecules
as their
carbon
source
Heterotrophic
microorganisms
has
extraordinary flexibility
with
respect
to
carbon
sources
Actinomycetes
: common
soil
bacteria
degrade
the
paraffin,
amyl alcohol and even
rubber
Burkholderia cepacia
: use
100 different
carbon
compounds
Leptospira
: use long chain fatty
acids
as the
major
source of
carbon
Microorganisms can be classified as autotrophs or heterotrophs on the basis of the
preferred source of carbon.
There are two sources of energy available to organisms.
•
Light energy:
•
Chemical energy: Energy derived from oxidising organic or inorganic molecules.
•
PHOTOTROPHS : Use light as energy source
•
CHEMOTROPHS : energy obtained from oxidation of chemical compounds
•
LITHOTROPHS (rock eaters) : Reduced inorganic substance as energy source
•
ORGANOTROPHS : extract electrons from reduced organic source
•
Majority of the microorganisms studied so far are Photolithotrophic autotrophs or
chemoorganotrophic heterotrophs
Major
nutritional types
of
microorganisms
Phototrophic bacteria
play
important
roles
in
aquatic
ecosystems,
where they can
cause blooms
(a)
A
cyanobacterial
and an
algal
bloom
in a
eutrophic
pond
(b)
Purple sulfur bacteria
growing
in a
bog
(c)
A
bloom of
purple
sulfur bacteria
in a
sewage
lagoon
Phototrophic
Bacteria
Chemolithotrophic
Bacteria
(a)
Transmission
electron micrograph
of
Nitrobacter winogradskyi
,
an
organism
that
uses
nitrite
as its
source
of
energy
(b)
Light micrograph
of
Beggiatoa alba
,
an
organism
that uses
hydrogen
sulfide
as its
energy source and
organic
molecules as
carbon
sources.
The dark spots
within
the
filaments
are
granules of
elemental
sulfur produced
when
hydrogen
sulfide is
oxidized
Requirements
for
Phosphorus,
Nitrogen
and
S
u
l
f
ur
Nitrogen
:
synthesis
of
amino acids, purines, pyrimidines,
some
carbohydrates
and lipids,
enzyme
cofactor
Some incorporate
ammonia
directly
through
the action
of
enzymes
such
as glutamate
dehydrogenase
or glutamine
synthetase
and glutamine
synthase
Phototrophs
and
chemotrophic
microbes
Nitrogen
Fixation
:
Variety
of
bacteria
(Cyanobacteria, Symbiotic bacterium
Rhizobium)
Assimilate atmospheric
nitrogen
(N
2
) by
reducing
it to
ammonium
Nitrate
Ammonia
Incorporated
Assimilatory
nitrate
reduction
P
h
o
spho
r
us
Phosphorus
present
in
nucleic
acid, phospholipids,
nucleotides
(ATP),
cofactors, some proteins
and other
cell
components
Use
of
inorganic
phosphate as
phosphorous
source
which is
directly
incorporated
Aquatic environments
: Low phosphate levels
limits microbial
growth
E.coli uses organic
and
inorganic
phosphate
Organophosphate
Hexose
6-phosphate
Taken
up
directly
by the
cell
Others
Inorganic
P
h
osp
h
ate
Transported
across
plasma
membrane
S
u
l
fur
S
u
lfur
Ami
n
o
acids
Biotin
Carbohy
drates
Thiamine
Microorganisms
use
sulfate
as a
source
of
sulfur
Reduce
it
by assimilatory
sulfate
reduction
Reduced
form
of sulfur such
as
cysteine
is also
used
Growth
Factors
Organic
compounds
that are
essential cell components
or
precursors
of such
components
but
cannot
be
synthesised by
the
organism
Vitamin
Functio
n
s
Biot
i
n
One carbon
metabolism,
CO
2
fixation
Leuconostoc
mesenteroids
Saccharomyces cerevisiae
Acanthamoeba
castellanii
Folic
acid
One
carbon
m
e
t
abol
i
sm
Tetrahymena
spp.
Enterococcus
fecalis
Riboflavin
(B2)
Precursor
of
FAD
&
FMN
Caulobacter
vibriodes
Dictyostellium
spp.
Thiamine
(B1)
Aldehyde
group
transfer
Bacillus
anthracis
Colpidium campylum
Ochromonas
malhamensis
Pantothenic
acid
Precursor
of
coenzyme
A
Proteus
morganii
Functions
of some common
vitamins
in
microorganism
Examples
Nutr
i
ent
uptake
Diff
u
sion
Active
t
r
ansport
Group
t
r
ansloc
a
t
i
on
Uptake
of nutrients by the
cell
A
solid/liquid
preparation
used
to
grow,
transport,
and
store
microorganisms
Complex
liquid
media
(urine,
chicken/
meat broth)-
Louis
Pasteur
Solid
media
(Potato
surface,
gelatin):
Robert
Koch
•
Gelatin melts
at
24
º
C
•
Microbes used
it as a
substrate
Agar
was
first
described
for
use
in
microbiology by
Walter
Hesse
Culture
Media
Culture
Media
s of
culture
media
Car
b
on
source
Energy
source
Nitrogen
source
Sal
ts
pH
Growth
factors
Ind
icator
s
s
Oxidatio
n
reductio
n
Inhibit
p
o
o
r
tenti
R
al
equirement
Culture
Media
P
h
ys
i
cal
Nature
Liquid
Semi
solid
So
l
id
Def
i
ned
C
o
mplex
Functio
n
al
Type
Supportive
Enriched
Selective
D
i
f
ferenti
a
l
Types
of
Media
Chemical
Compos
i
tion
Liquid
and
solidified media
are routinely
used in
microbiology
labs, solidified media
are
particularly
important
Both
defined
and
complex
media can be solidified with
the addition
of
1.0
to
2.0%
agar;
most
commonly
1.5%
is
used
Agar
–
Sulp
h
at
ed
p
o
lym
e
r
(D
-
g
alac
t
ose
,
3,6
-
a
n
h
y
d
r
o
-L
-
g
alac
t
ose
,
and
D
-
gl
u
c
u
r
onic
acid)
Extracted
from
red
algae
Melting
temperature-
about 90°C and
Solidifying
temperature-
45°C
M
ic
r
obe
s
g
r
o
w
i
n
g
o
n
a
g
ar
m
e
diu
m
c
a
n
be
incub
at
ed
a
t
a
w
i
d
e
r
a
ng
e
of
temperatures
Agar is
an
excellent
hardening
agent
because
most microorganisms
cannot
degrade
it
Other solidifying
agents -silica gel
is
used
to grow
autotrophic
bacteria
Culture
Media
Defined or Synthetic
medium
•
All
chemical
c
omponents are
know
iquid
form
(broth)
or
n in
defined
solidified
by
medium.
an agent
such
as
in
research, as
it
is
o
ften desirable
to
know
what
•
Can
be
in
a l
agar
•
Widely
used
the
experim
ental
microorganism
is
g
m
e
t
abolizin
o
t
olithot
r
ophi
c
au
t
o
t
r
oph
s
(
c
y
a
•
Culture
ph
pho
t
o
s
y
n
th
e
t
ic
protists),
chemoor
ganotrophic
h
edia
are
as
simple,
b
ut
may
be
nobac
t
e
ria
and
eterotrophs
constructed
from
•
All
defined
m
dozens
of
components
Culture
Media
Complex
media
Media
that
contain
some ingredients of
unknown
chemical composition
Single
c
omp
l
e
x
m
e
diu
m
m
a
y
be
su
f
ficie
n
tly
r
i
ch
t
o
c
omp
l
e
t
e
ly
m
e
e
t
the
nutritional
requirements
of
many
different
microorganisms
The nutritional
requirements
of
a
particular
microorganism are
unknown,
and
thus a
defined medium
cannot be
constructed
Undefined components
like
peptones, meat
extract,
and
yeast
extract
Nutrient broth,
tryptic
soy broth,
and
MacConkey
agar
Culture
Media
General
purpose media
or
supportive media
:
they sustain
the
growth
of
many microorganisms.
Ex:
tryptic
soy broth
and tryptic
soy
agar
Enriched
media:
Blood and
other special nutrients
may
be
added
to
general
purpose media
to
encourage
the
growth
of
fastidious microbes.
These specially
fortified
media
(e.g.,
blood
agar)
Selective media:
favour
the
growth
of particular
microorganisms
Differential
media:
are
media
that distinguish among
different
groups
of
microbes
and
even
permit
tentative
identification
of microorganisms
based on their biological
characteristics
(e.g.,
blood
agar:
hemolytic
and
non-hemolytic
bacteria)
Functional
types of
media
Nutritional requirements of microorganisms play a crucial role in their growth and functionality. The essential nutrients include carbon, oxygen, iron, macroelements, micronutrients, and trace elements. Microorganisms need a balanced mixture of nutrients for biosynthesis, energy release, and various metabolic processes. Different types of microorganisms, such as autotrophs and heterotrophs, have specific ways of obtaining and utilizing nutrients to support their growth and survival.
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Presentation Transcript
Nutritional Requirement by Microorganisms
INTRODUCTION Nutrients are substances used in biosynthesis and energy release and therefore are required for microbial growth
Common Nutrient Requirements Carbon Oxygen Iron 95% cells dry weight Macroelements/ Macronutrients Magnesium Hydrogen Calcium Nitrogen Phosphorous Sulphur Potassium The first six (C, O, H, N, S and P) : components of carbohydrates, lipids and proteins K+: enzyme -protein synthesis Ca2+ : heat resistance of bacterial endospores Mg2+ : cofactors, stabilise the cell membrane and ribosomes Fe2+ and Fe3+ : part of cytochrome and cofactors for enzymes and ECP
Micronutrients/ Trace elements : Several nutrients which are required in small amounts Ubiquitous and normally part of enzymes and cofactors Aid in catalysis of reaction and maintenance of protein structure Mn2+: transfer of phosphate groups Manganese Mo2+ : nitrogenfixation Co2+ : component of vitaminB12 Copper Zinc Micro nutri ents Nickel Cobalt Molybdenum Hence microorganisms require a balanced mixture of nutrients
Requirements for Carbon, Hydrogen, Oxygen and Electrons All organisms need carbon, oxygen, hydrogen and source of electrons CARBON : Skeleton/backbone of all organic molecules from which the organism is built HYDROGEN & OXYGEN: Important elements found in the organic molecules ELECTRONS Electron transport chain and the oxidation reduction reactions- energy for use in cellular work reduced Reduce molecules during biosynthesis (CO2 molecules) organic
AUTOTROPHS : use only CO2 as a sole source of carbon obtain energy from light or reduced inorganicmolecule Because CO2 cannot supply their energy needs, they must obtain energy from other sources, such as light or reduced inorganic molecules HETEROTROPHS : organisms that use reduced, preformed organic molecules as their carbonsource Heterotrophic microorganisms has extraordinary flexibility with respect to carbon sources Actinomycetes : common soil bacteria degrade the paraffin, amyl alcohol and even rubber Burkholderia cepacia : use 100 different carbon compounds Leptospira : use long chain fatty acids as the major source of carbon
Microorganisms can be classified as autotrophs or heterotrophs on the basis of the preferred source of carbon. There are two sources of energy available to organisms. Light energy: Chemical energy: Energy derived from oxidising organic or inorganic molecules. PHOTOTROPHS : Use light as energy source CHEMOTROPHS : energy obtained from oxidation of chemical compounds LITHOTROPHS (rock eaters) : Reduced inorganic substance as energy source ORGANOTROPHS : extract electrons from reduced organic source Majority of the microorganisms studied so far are Photolithotrophic autotrophs or chemoorganotrophic heterotrophs
Major nutritional types of microorganisms NURTIONAL TYPE CARBON SOURCE ENERGY SOURCE ELECTRON SOURCE REPRESENTATIVE MICROORGANISMS Photolithography CO2 Light Inorganice- donor Purple and green sulfur bacteria, cynobacteria Photoorganoheterophy Organic carbon Light Organic e- donor Purple nonsulfur bacteria, green nonsulfurbacteria Chemolithoautotrophy CO2 Inorganic chemicals Inorganice- donor Sulfur, iron, hydrogen- oxidizing bacteria, methanogens Chemolithoheterotrophy Organic carbon Inorganic chemicals Inorganic e- donor Some sulfur oxidizing bacteria Chemoorganoheterotrophy Organic carbon Organic chemicals Organice- donor Fungi, protists and many archaea
Phototrophic Bacteria Phototrophic bacteria play important roles in aquatic ecosystems, where they can cause blooms (a) A cyanobacterial and an algal bloom in a eutrophicpond (b) Purple sulfur bacteria growing in a bog (c) A bloom of purple sulfur bacteria in a sewage lagoon
Chemolithotrophic Bacteria (a)Transmission electron micrograph of Nitrobacterwinogradskyi,an organism that uses nitrite as its source of energy (b)Light micrograph of Beggiatoa alba, an organism that uses hydrogen sulfide as its energy source and organic molecules as carbon sources. The dark spots within the filaments are granules of elemental sulfur producedwhen hydrogensulfide is oxidized
Requirements for Phosphorus, Nitrogen and Sulfur Nitrogen : synthesis of amino acids, purines, pyrimidines, some carbohydrates and lipids, enzyme cofactor Some incorporate ammonia directly through the action of enzymes such as glutamate dehydrogenase or glutamine synthetase and glutamine synthase Phototrophs and chemotrophic microbes Assimilatory Incorporated Nitrate Ammonia nitrate reduction Nitrogen Fixation : Variety of bacteria (Cyanobacteria, Symbiotic bacterium Rhizobium) Assimilate atmospheric nitrogen (N2) by reducing it to ammonium
Phosphorus Phosphorus present in nucleic acid, phospholipids, nucleotides (ATP), cofactors, some proteins and other cellcomponents Use of inorganic phosphate as phosphorous source which is directly incorporated Aquatic environments : Low phosphate levels limits microbialgrowth E.coli uses organic and inorganic phosphate Organophosphate Others Hexose 6-phosphate Transported across plasma membrane T aken up directly by the cell Inorganic Phosphate
Sulfur Microorganisms use sulfate as a source ofsulfur Reduce it by assimilatory sulfatereduction Amino acids Reduced form of sulfur such as cysteine is alsoused Sulfur Thiamine Biotin Carbohy drates
Growth Factors Organic compounds that are essential cell components or precursors of such components but cannot be synthesised by theorganism Vitamin Biotin Functions One carbon metabolism,CO2 fixation Examples Leuconostoc mesenteroids Saccharomyces cerevisiae Acanthamoebacastellanii Folic acid Onecarbon metabolism Tetrahymena spp. Enterococcus fecalis Riboflavin (B2) Precursor of FAD & FMN Caulobacter vibriodes Dictyostellium spp. Thiamine(B1) Aldehyde group transfer Bacillus anthracis Colpidium campylum Ochromonas malhamensis Pantothenic acid Precursorof coenzyme A Proteus morganii Functions of some common vitamins in microorganism
Uptake of nutrients by the cell Diffusion Nutrient uptake Active transport Group translocation
Culture Media A solid/liquid preparation used to grow, transport, and store microorganisms Complex liquid media (urine, chicken/ meat broth)- Louis Pasteur Solid media (Potato surface, gelatin): Robert Koch Gelatin melts at 24 C Microbes used it as a substrate Agar was first described for use in microbiology by Walter Hesse
Culture Media Oxidatio n reductio n Carbon source Energy source InhibitpoortentiRalequirement Nitrogen source s s of culture media Indicator s Salts Growth factors pH
Culture Media Types of Media Physical Nature Functional Type Chemical Composition Liquid Defined Supportive Semi solid Complex Enriched Solid Selective Differential
Culture Media Liquid and solidified media are routinely used in microbiology labs, solidified media are particularly important Both defined and complex media can be solidified with the addition of 1.0 to 2.0% agar; most commonly 1.5% is used Agar Sulphated polymer (D-galactose, 3,6-anhydro-L-galactose, and D-glucuronic acid) Extracted from red algae Melting temperature- about 90 C and Solidifying temperature- 45 C Microbes growing on agar medium can be incubated at a wide range of temperatures Agar is an excellent hardening agent because most microorganisms cannot degrade it Other solidifying agents -silica gel is used to grow autotrophic bacteria
Culture Media Defined or Synthetic medium medium. All chemicalcomponents areknow n in defined Can be in a l agar an agent such as iquid form (broth) or solidified by Widely used in research, as it isoften desirable to know what the experimental microorganismis g metabolizin Culture photosynthetic protists),chemoorganotrophich otolithotrophic ph nobacteria eterotrophs and autotrophs (cya constructed from All defined m edia are as simple, b ut may be dozens of components
Culture Media Complex media Media that contain some ingredients of unknown chemical composition Single complex medium may be sufficiently rich to completely meet the nutritional requirements of many different microorganisms The nutritional requirements of a particular microorganism are unknown, and thus a defined medium cannot be constructed Undefined components like peptones, meat extract, and yeast extract Nutrient broth, tryptic soy broth, and MacConkey agar Tryptic Soy Broth Amt (g/ltr) Tryptone (pancreatic digestof casein) 17 Peptone (soybeandigest) 3 Glucose 2.5 Sodiumchloride 5 Dipotassiumphosphate 2.5
Functional types of media General purpose media or supportive media: they sustain the growth of many microorganisms. Ex: tryptic soy broth and tryptic soy agar Enriched media: Blood and other special nutrients may be added to general purpose media to encourage the growth of fastidious microbes. These specially fortified media (e.g., blood agar) Selective media: favour the growth of particular microorganisms Differential media: are media that distinguish among different groups of microbes and even permit tentative identification of microorganisms based on their biological characteristics (e.g., blood agar: hemolytic and non-hemolytic bacteria)
