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BIO 425Industrial Microbiology

Seyhun YURDUGL

Lecture 1

Introduction: A glance to microbialworld

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C

ontent outline Introduction to microbiology

General properties of prokaryotes Some basic concepts in microbiology

Spore morphology

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INTRODUCTION TO

MICROBIOLOGY The study of microorganisms (m/os),

including viruses

A single m/o is able to carry out its lifeprocesses of growth, energy generation andreproduction independently.

Prokaryotic organisms

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General properties of prokaryotes Have a nuclear region nucleoid.

Not surrounded by a membrane.

Have a single DNA whose division is notmitotic.

Two main groups:

-Bacteria

-Archaea

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Typical bacterial structure

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Archaea Most are anaerobic.

Present in extreme environments.

i. e. hot springs, hot spa, extreme salty, highacidic, alkaline, salty soils.

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Thermophilus aquaticus

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Some basic concepts in

Microbiology Pure culture: A culture consisting of only

one kind of m/o.

should be grown in the lab conditions whereappropriate nutrients and environmentalconditions must be provided.

exclude unwanted organisms(contamination) during cultivation.

use Aseptic technique.

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Temperature profile for main genera

of bacteria

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SEM picture forB

acillus spp.

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Some basic concepts in

Microbiology-2 Culture media:

For growth and maintenance of m/os.

Broth (The liquid culture)

Agar (The solid culture)-petri dish, slant.

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Cross inoculation on blood agar

S.aureus vsH.influenzae:

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The impact of microorganisms on human

affairs

Agriculture: N2 fixation, nutrient cycling, animal

husbandry. Food: Food preservation, fermented foods, food

additives.

Disease: Identifying new diseases, treatment and

cure, disease prevention.

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The impact of microorganisms (m/o)s on

human affairs-2 Energy/Environment: Biofuels (methanol and

ethanol) production, Bioremediation, Microbial

mining. Biotechnology: Genetically modified organisms,

Production of pharmaceuticals, Gene therapy forcertain diseases.

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C

ell structure of bacteria Cytoplasmic membrane

Cell wall

Ribosomes(protein & RNA)

Inclusions(Storage material)

Nucleoid region(DNA is present in a moreor less free state)

Flagellum

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Morphology of m/os Cocci (Spherical / ovoid)

Rod (Cylindirical shape)

Spirilla(Spiral shaped or curved) Spirochaetes (Tightly coiled bacteria)

Appendaged bacteria(Extension-bearing

like long tubes or stalks) Filamentous bacteria(long-thin cells or

chains of cells)

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Different morphological structures

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C

ell wall structure of bacteria G(+)

G(-)

G(-): quite complex, multilayered structure.

G(+): single type of molecule, much thicker.

Rigid layer for both G(-) and G(+) is

peptidoglycan(Murein). Composed of N-acetyl glucosamine and N-acetyl

muramic acid.

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Structure of peptidoglycan A small group of aminoacids consisting

L-alanine

D-alanine

D-glutamic acid

Lysine or Diaminopimelic acid(DAP) These molecules are connected to formglycan tetrapeptide

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Peptidoglycan structure

A thin sheet in which the glycan chainsformed by the sugars,

are connected by peptide cross-links formedby the aminoacid.

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Peptidoglycan structure G(-): Direct peptide linkage of the amino group of

DAP to the carboxyl group of the terminal D-alanine

Besides peptidoglycan, structure is mostlycomposed of lipopolysaccharide(LPS)

G(+):A peptide interbridge is the base of crosslinking & # of cross-linking aminoacid varies

from organism to organism Composed of 90 % peptidoglycan and teichoicacid

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Endospores Special structures of bacteria,

produced within the cell

can not be destroyed easily even by harshchemicals,

Resistant to radiation(UV), acids and

drying, can remain dormant for extremely long

periods of time.

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Spore structure

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LITERATUREC

ITED Brock, T. D. , Biology of Microorganisms, Eighth

Edition,Prentice-Hall International Inc., New

Jersey, 1997. kmen, Z. A. , Food Microbiology Laboratory

Book, Food Engineering Department, Middle EastTechnical University, Ankara, 1995.

Pelczar, M. J. ; Chan, E. C. S. ,Krieg, N. R.Microbiology, Fifth edition, Mc Graw Hill Inc.Singapore, 1986.