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In natural environment, microbial cells will almost always be in mixed cultured. They have to interact each other, but these interaction are limited by the potential of each cell. Each species of the environmental microbe has specific potential and some of them are potential to produce useful industrial products. The microorganisms encompass the three groups: Viruses, Prokaryotes, and Eukaryotes Other microbiologists claim three Kingdoms of five Kingdoms of cellular life are microorganisms, namely: Monera : bacteria (procaryotae) and blue green algae Protista : protozoa, eukaryotic algae, slime moulds and flagellated fungi Fungi : non-flagellated fungi It is not having a cell structure It is dependent on its host’s metabolic machinery Its structure of nucleic acid, DNA or RNA, is surrounded by protein and sometimes an outer lipid-rich envelope Purple bacteria and the green bacteria Gliding bacteria Sheathed bacteria Spirochaetes Spiral and curve bacteria Gram-negative aerobic rods and cocci Gram-negative facultative anaerobic rods Gram-negative anaerobic bacteria Methane producing bacteria Gram-positive cocci Gram-positive endospore-forming rods and cocci Group of Lactobacillaceae Actinomycetes Rickettsias Mycoplasmas Cyanophyceae or Cyanobacteria The students are divided into several groups and each group… …discuss these grouping of prokaryote microorganisms (the bacteria) and the beneficial of them in industrial purposes. Bacteria are unicellular, most ca. 0.5-1.0 x 2.0-10 µm in size. They can be motile or non-motile Cytoplasmic materials are enclosed in a rigid wall on the surface and a membrane beneath the wall, and they are immobile. The membrane contains energy generating components. The genetic materials (structural and plasmid DNA) are circular, not enclosed in nuclear membrane, and do not contain basic protein such as histones. Cell division is by binary fission. Can also have flagella, capsules, surface layer protein, and pili for specific function. Some also form endospores (one per cell) Gram-positive cells or Gram-negative cells If we look at the shape and size, called morphology, it is more simple to use them for grouping the bacteria. The most common shapes are rod-like, bacillus (plural: bacilli), and sperichal, coccus (plural: cocci) The rods form vary from short rods (almost look like cocci) to very long filaments. Also form spiral and corkscrew, oval (coccoid), comma, and branch structure. Eukaryotic cells: are generally much larger than prokaryotic cells have rigid cell walls and thin plasma membranes (contain sterol) the cell wall does not have mucopeptide and is composed of carbohydrates the cytoplasm is mobile (streaming) and contain organelles the DNA is linear (chromosomes), contains histones, and is enclosed in a nuclear membrane. The eukaryotic microorganisms are: Fungi Algae Protozoa Yeasts – unicellular Molds – multicellular Molds are non-motile, filamentous and branches the cell wall is composed of cellulose, chitin, or both are composed of hyphae (large number of filaments), an aggregate of hyphae called mycellium. a hyphae can be vegetative or reproductive, the reproductive hyphae usually extend and form exospores, either free (conidia) or in sack (sporangium). Shape, size and color of spores are used for taxonomic classification. Yeast the cells are oval, spherical, or elongated (5- 30 x 2-10 µm), non-motile. the cell wall contains polysaccharides (glycans), protein and lipids. the cytoplasm has a finely granular appearance for ribosomes and organelles. the nucleus is well defined with nuclear membrane The algae are photosynthetic eukaryotic microorganisms. The major primary producers in the sea and in lakes, but are also found in the surface layer of soil. Many can live heterotrophically. The algae have been classified traditionally by pigmentation and life cycle: › Rhodophyceae, the red algae: marrine, multicellular, › › › › › › › › immotile, some unicellular Chlorophyceae: many planktonic species, freshwater and marine, motil by flagella,multicellular. Prasinophyceae: unicellular planctonic flagellated organisms, marine. Euglenophyceae: unicells, motile by single flagellum, common in nutrition rich freshwater pools, also found in the sea and in the soil. Bacillarophyceae, diatoms: in mcroplankton of sea and lakes, motile. Dinophyceae, dinoflagellates: in microplankton of seas and lake s, motile, some are non photosynthetic. Crysophyceae: found in freshwater, also the marine silicoflagellates, biflagellate cells. Haptophyceae: biflagellate planktonic algae, in marine, blooms of this species can give the sea a milky appearance. Cryptophyceae: unicellular flagellates found as minor components of plankton. algae… classified traditionally…: –Xanthophyceae: multicellular, but few unicellular in plankton and soil. –Eustigmatophyceae: unicellular, in freshwater, sometime found in soil. Among aquatic microorganisms microalgae are a very interesting source of a wide range of compounds. They do not only have the capacity to produce high-value compounds, but also the ability to do it using only sunlight, carbon dioxide and sea water. Peptides and protein: lectins (glycoprotein) have proved to be useful for clinical diagnosis and other health application. Red algae (Bryothamnion triquetrum, Solieria robusta, Ceratodiction spongiosum) -carotene/canthaxanthin and astaxanthin: green-algae, Haematococcus pluvialis. Seaweed polysaccharides Lipid – polyunsaturated fatty acid Exhibit a very wide range of form and way of life. Many are predators on bacteria, fungi, algae, yeast, or other protozoa, while some others are parasitic in animals. Sarcomastigophora: the flagellated cells and amoeboid protozoa, some are human pathogens such as Trypanosoma brucei in the bloodstream, and Entamoeba histolytica in the gut. Some flagellates are symbionts in termite guts. Ciliphora: includes the familiar ciliates, Tetrahymena and Paramecium. Vorticella species are very important in sewage treatment processes. Sporozoa: totally endoparasitic in animals or man, Plasmodium cause malaria. Factors inherent to the media/substrate of the growth are considered intrinsic factors which may stimulate or retard the growth of microbial, including: › pH (acidity) › Water Activity (moisture) › Oxidation-reduction potential (oxygen or ionic) › Nutrition (food) Environment factors that influence microbial growth are considered extrinsic factors, such as: › Temperature Each species of microbe has an optimal temperature of growth Temperature regulate the expression of gene The growth temperature can also influence a cell’s thermal sensitivity. › Gas composition It relates to the oxygen concentration. Many microbes are inhibited in low concentration or without of oxygen, but some may grow even though in the absent of oxygen. It is applied in food preservation using controlled or modified atmosphere storage. Four phase of microbial growth: Log Total mikroba Fase lag Fase logaritmik Fase stasioner Waktu Fase kematian During the log, or exponential, growth phase microbes (bacteria) reproduce by binary fision. Thus, during this phase, firstorder reaction can be used to describe the change in cell number The number of microbes (N) at any time is directly proportional to the initial number of microbes (No) The microbiologists frequently use td to describe growth rates of microbes and µ to describe specific growth rates The killing of microbes by energy input, acid, bacteriocin, and other lethal agents is also governed by first-order kinetics By this kinetic reaction, it can be predicted the number of microbes (viable cells) remaining after treatment, such as in sterilization process. In microbiology, D value (amount of time required to reduce No by 90%) is the most frequently used as kinetic constant. D values are inversely proportional to the rate constant, k, for a given temperature. Growtha Thermal inactivationb Iradiationc N = Noeµt N = Noe-kt N = Noe-D/Do 2.3log(N/No) = µ∆t 2.3log(N/No) = -(k∆t) ∆t = [2.3 log(N/No)]/µ ∆t = -[2.3 log(N/No)]/k td = 0.693/µ D = 2.3/k aN, cell number (cfu/g); No, initial cell number (cfu/g); t, time (h); µ, specific growth rate (h-1); td, doubling time (h); bk, rate constant (h-1); D, decimal reduction time (h); cDo, rate constant (h-1); D, dose (Gy) µ (h-1) td (h) Optimal conditions 2.3 0.3 Limited nutrients 0.20 3.46 Psychotroph, 5oC 0.023 30 0.1 – 0.3 6.9 – 20 Organism Bacteria Molds, optimal The availability of suitable nutrients is clearly a major factor determining whether the microbes will grow or not in a particular environment. There are four useful ways to classify potential nutrient mlocules: › As esential, or useful but dispensable › Used as building blocks for macromolecules, or as energy sources, or as both › As macronutrient required in large quantities, or as micronutrients › As macromolecules requiring breakdown before entry to the cell, or small molecules readily entering as soluble nutrients. The major elements of the cell are carbon, hydrogen, oxygen, nitrogen, sulphur and phosphorous. Carbon dioxide is utilized as sole carbon source only by autotrophs. Carbohydrates are commonly utilized as sources of carbon. Organic acids are readily used directly as sources of carbon by most microbes. Protein and their constituent organic acids are utilized as carbon sources by proteolitic microbes. Nitrogen is abundant as gaseous dinitrogen, but only few prokaryotic organisms and some of bluegreen algae can utilize it. Other sources of nitrogen, such as nitrate, amonia, amino acids, nucleotides, uric acid and urea, can also provide cells’ requirements for nitrogen. Some organisms can utilize hydrogen sulphide as source of sulphur. Organic sulphur as amino acids cysteine and methionine can also be used. Probably all organisms can utilize soluble inorganic phosphate.