Microbial Diversity

1. MicrobialDiversity • Life can exist in extreme environments. • Living cells can be found almost anywhere that water is in the liquid state. • The right temperature, pH, moisture levels vary from one microorganism to another. • Psychrophiles, cells that grow best at low temperatures below 20oC. Some cells can grow at -20oC (in a brine to prevent freezing). • Mesophiles have temperature optima in the range of 20 to 50oC • Thermophiles grow best at temperatures greater than 50oC. Some cells can grow at 120oC (where water is under high enough pressure to prevent boiling.

2. Many organisms have pH optima far from neutrality; some prefer pH values down to 1 or 2, while others may grow well at pH 9. • Although most microorganisms can grow only where water activity is high, others can grow on hardly moist solid surfaces or in solutions with high salt concentrations.

3. Aerobic microorganisms require O2 for growth and metabolism. • Anaerobic microorganisms are inhibited by the presence of O2 • Facultative organisms can switch the metabolic pathways

4. Cyanobacteria(Bluegreenalgae) • Can grow with only little moisture • A few dissolved minerals • These bacteria are photosynthetic and can convert CO2 from the atmosphere into the organic compounds • They can convert N2 to NH3

5. Organisms from extreme environments are called extremophiles • They provide the human race with important tools for processes to make useful chemicals and medicinals. • Can be used in the recovery of metals from low-grade ores or in the desulfurization of coal or other fuels

6. Microorganisms can be in a wide range of sizes and shapes. • Spherical (Coccus- cocci) • Cylindrical (rod or bacillus-bacilli) • Ellipsoidal (Coccus- cocci) • Spiral (spirillum-spirilla) • Pleomorphic cells (change shape in response to changes in their local environment)

7. NamingCells • Taxonomy is the development of approaches to organize and summarize our knowledge about the variety of organisms that exist. • Taxonomy is concerned with approaches to classification, nomenculature refers to the actual naming of organisms.

8. Howto name microorganisms • For microorganisms we use a dual name(binary nomenculature). • The names are given in Latin or are Latinized. • A genus is a group of related species, while a species includes organisms that are substantially alike. • Escherichia is the genus and coli the species.

9. When writing a report or paper, when the organism is first mentioned, the full name is given but in subsequent discussion to abbreviate the genus name the first letter of genus is written. • Although organisms that belong to the same species all share the same major characteristics, there are significant variations within species.

10. A R. delemar used in one laboratory may differ from that used in another. • Various strains and substrains are designated by the addition of letters and numbers. • E. coli B/rA will differ in growth and physiologica properties from E. coli K12.

11. Howtoclassifymicroorganisms • There is no universal agreement on how to classify microorganisms. • There are two primary cell types: eucaryotic and procaryotic. • The primary difference between them is the presence or absence of a membrane around the cell’s genetic information.

12. PROTIST KINGDOM • Procaryotes • have a simple structure with a single chromosome • No nuclear membrane, no organelles, such as mitochondria, endoplasmic reticulum.

13. PROTIST KINGDOM • Eucaryotic cells • have more than one chromosome (DNA molecule) in the nucleus. • have a true nuclear membrane • contain mitochondria • Endoplasmic reticulum • Golgi apparatus • a variety of specialized organelles

14. PrimarySubdivisions of CellularOrganisms • EucaryotesEucaryotic Plants, Animals, Protists (Algae, fungi, protozoa) EubacteriaProcaryotic Mostbacteria ArchaebacteriaProcaryotic Methanogens, halophiles, thermoacidophiles

15. PROCARYOTES • The size of procaryotes vary from 0.5 to 3 μm in equivalent radius. • Different species have different shapes • Spherical or coccus (e.g., Staphylococci) • Cylindirical or bacillus (E. Coli) • Spiral or spirillum (Rhodospirillum) • Procaryotic cells grow rapidly, have doubling times of one-half hour to several hours. • They can use a variety of nutrients as carbon source, containing carbohydrates, hydrocarbons, proteins and CO2.

17. PROCARYOTESEubacteria • Gram-negative cell (E. coli) has an outer membrane supported by a thin peptidoglycan layer. • Peptidoglycan is a complex polysaccharide with amino acids and forms a chain-link fence. • A second membrane (the inner or cytoplasmic membrane) exits and is separated from the outer membrane by the periplasmic space.

18. Gram-negativecell • The cytoplasmic membrane contains about 50% protein, 30% lipids, and 20% carbohydrates. • The cell envelope serves to retain important cellular compounds and to selectively exclude undesirable compounds in the environment. • Loss of membrane integrity leads to cell lysis ( cells breaking open) and cell death. • The cell envolope has great importance for the transport of selected material in and out of the cell.

19. Gram-PositiveCells • Gram-positive cells (Bacillus subtilis) do not have an outer membrane, have a very thick, rigid cell wall with multiple layers of peptidoglycan. They contain teichoic acids covalently bonded to the peptidoglycan. As gram-positive bacteria have only a cytoplasmic membrane,they are much better suited to excreation of proteins. Such secretion can be technologically important when the protein is a desired product.

20. Mycoplasma • Mycoplasma (not gram positive or gram negative) have no cell walls. • They are important clinically (atypical pneumania). • They contaminate media used industrially for animal cell culture.

21. Actinomycetes are bacteria, but, morphologically, resemble molds with their long and highly branched hyphae. • The lack of a nuclear membrane and the composition of the cell wall require classification of bacteria. • Actinomycetes are important sources of antibiotics. • Certain actinomycetes have amylolytic and cellulolytic enzymes and are used in hydrolysis of starch and cellulose. • Actinomyces, Thermomonospora, streptomyces are examples of genera belonging to this group.

22. Cyanobacteria • Other differences within the eubacteria can be made based on cellular nutrition and energy metabolism. One important example is photosynthesis. • Cyanobacteria(blue-green algae) have chlorophyll and fix CO2 into sugars. • Anoxygenic photosynthetic bacteria(purple and green bacteria) have light-gathering pigments called bacteriochlorophyll. • Unlike true photosynthesis, the purple and green bacteria do not obtain reducing power from the splitting of water and do not form oxygen.

23. Procaryotesmayhavevisiblestructureswhenviewedunderthemicroscope.Procaryotesmayhavevisiblestructureswhenviewedunderthemicroscope. • Ribosomesarethe site of protein synthesis. The size of ribosome is 10 to 20 nmandconsists of 63% RNA and 37% protein. • Storagegranulesareused as a source of keymetabolitesandcontainpolysaccharides, lipids, sulfurgranules. Thesizes of storagegranuleschangebetween 0.5 to 1 μm. • Bacterialspores (intacellularsporescalledendospores) areproduced as a resistance of adverseconditionssuch as hightemperature, radiation, toxicchemicals. Thecommonconcentration is 1 sporepercell, with a spore size of 1 μm. Spores can germinateunderfavorablegrowthconditionstoyieldactivelygrowingbacteria. • Volutin is granularintracellularstructure, made of inorganicpolymetaphosphates. • Somephotosyntheticbacteriahavechromatophoresthatarelargeinclusionbodies (50 to 100 nm) used in photosynthesisfortheabsorption of light.

24. Archaebacteria • The archaebacteria are similar under the microscope with many of the eubacteria. • However, these cells differ greatly at the molecular level. • In many ways the archaebacteria are as similar to the eucaryotes as they are to the eubacteria.

25. Differencesbetweenarchaebacteriaandeubacteria • Archaebacteria have no peptidoglycan • The nucleotide sequences in the ribosomal RNA are similar within the archaebacteria but different from eubacteria • The lipid composition of the cytoplasmic membrane is very different for the two groups.

26. Archaebacteria • The archae bacteria live in extreme environments and have unusual metabolism. • Methanogens (methane-producing bacteria) as well as thermoacidophiles belong to this group. • The thermoacidophiles can grow at high temperatures and low pH values. • The halobacteria can live only in very strong salt solutions. • These microorganisms are important sources for catalically active enzymes (proteins).

27. BACTERIA CELL JOKE

28. BACILLUS SOIL BACTERIA

29. BACTERIA

30. BACTERIA CELL STRUCTURE

31. BACTERIA GROWTH

32. CYLINDIRICAL OR BACILLUS BACTERIA

33. CYLINDIRICAL OR BACILLUS BACTERIA

34. BACTERIUM CELL STRUCTURE

35. ECHERIA COLI

36. PATHOGENIC BACTERIA

37. EUCARYOTES • The nucleus of eucaryotic cells contains chromosomes as nuclear material (DNA molecules with associated small proteins), surrounded by a membrane. • The nucleolus is the site of ribosome synthesis. • Many chromosomes contain small amounts of RNA and basic proteins called histones attached to the DNA. • Each chromosome contains a single linear DNA molecule on which the histones are attached.

38. CELLULAR ORGANELLES • Mitochondria are the powerhouses of a eucaryotic cell, where respiration and oxidative phosphorylation take place. • The mitochondria contain a complex system of inner membranes called cristae. • A mitochondria has its own DNA and protein-synthesizing machinery and reproduces independently.

39. CELLULAR ORGANELLES • The endoplasmic reticulum is a complex, convoluted membrane system leading from the cell membrane into the cell. • The rough endoplasmic reticulum contains ribosomes and is the site of protein synthesis and modifications of protein structure after synthesis. • The smooth endoplasmic reticulum is involved with lipid synthesis.

40. CELLULAR ORGANELLES • Lysosomes are very small membrane-bound particles that contain and release digestive enzymes. • Peroxisomes carry out oxidative reactions that produce hydrogen peroxide. • Glyoxysomes are very small membrane-bound particles that contain the enzymes of the glyoxylate cycle.

41. CELLULAR ORGANELLES • Golgibodiesareverysmallparticlescomposed of membraneaggregatesandareresponsibleforthesecretion of certainproteins. • Vacuolesaremembrane-boundorganelles of lowdensityandareresponsibleforfooddigestion, osmoticregulation, andwaste-productstorage. • Chloroplastsarerelativelylarge, chlorophyll-containing, greenorganellesthatareresponsibleforphotosynthesis in photosyntheticeucaryotes, such as algaeandplantcells.

42. SOME MICROORGANISMS • Pseudomonas sp. (bacterium) • Geotrichum candidum (yeast) • Mucor miehei (fungus) • Rhizopus delemar (fungus)

43. PSEUDOMONAS

44. GEOTRİCHUM CANDİDUM

45. MUCOR MIEHEI

46. RHİZOPUS DELEMAR

47. REFERANSLAR • Michael L. Shuler and Fikret Kargı, Bioprocess Engineering: Basic Concepts (2 nd Edition),PrenticeHall, New York, 2002. • 1. James E. Bailey and David F. Ollis, Biochemical Engineering Fundementals (2 nd Edition), McGraw-Hill, New York, 1986.