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Technical Microbio..
Tecnical Microbiolog
| Term | Definition |
|---|---|
| Technical Microbiology | - Industrial (white) biotechnology - Application of biotechnology for industrial purpose - Use of microorganism or part of them (enzymes) to produce industrially useful products |
| Introduction and History: Micro- Scale | Biology/Chemistry e.g. development of enzymes |
| Introduction and History: Lab- Scale | interactions biochemistry and process technology (e.g. enzymes in stirred reactor) |
| Introduction and History: Pilot- or industrial- Scale. | Process Technology (e.g. dimensioning of reactors) |
| Introduction and History: Bio-based Economy | -The application of biotechnology for the sustainable processing and production of chemicals, materials and fuels from biomass( organic renewable energy source), reduce significantly our dependence on coal, oil and gas. |
| Introduction and History: Bio-based Economy benefits | - Reduction in fossil fuels as raw material -Reduction in production cost - More efficient use of energy - More enviroment friendly - obtain new biomaterials |
| Introduction and History: Bio-based Economy application | - Food enzymes - Microorganism for drug production - Biopolymers from plants -Biofuels |
| The Organism Properties of a useful industrial microorganism (1) | - Genetically stabile - Efficient production of the target product - Limited or no need for vitamins and additional growth factor - Utilization of wide range of low cost and readily available carbon source - Accessibility to genetic manupulation |
| The Organism Properties of a useful industrial microorganism (2) | - Safety, non patogenicity and shouldn't produce toxic agents - Easy harvesting from the fermentation - Easy breakage, if the target is intracullular - production of limited by-products |
| The Organism Properties- Nice to have | - can withstand higher initial concentrations of carbon substrates -Product tolerance -Product location– is product excreted? (improve product tolerance, easier purification, correct form of some products -Ease of microorganism/medium separation |
| The Organism Screening | -Selecting the useful organisms/genes from a number of possibilities during process development or improvement -Can operate at the cell or gene (DNA) level - |
| The Organism Random Screening | After inducing the mutations ,survivors from the population are randomly picked and tested for their ability to produce the metabolite of interest (very large number of colonies must be tested) |
| The Organism Random Screening Advantage | over genetic engineering ,with minimal startup time and sustaining for years. |
| The Organism Random Screening Disdvantage | Non-targeted and non-specific. |
| The Organism Rational Screening | -Understanding of product metabolism and regulation, gives information about check points, suggest ways to isolate mutants. -Environmental conditions can be manipulated or chemicals can be bleded in the culture media to select mutants with desired traits |
| The Organism Rational Screening Applications | -Selection of mutants resistant to the antibiotic produced -Selection of morphological variants -Reversion of nonproducing mutants -Selective detoxification -Selection of overproducers of a biosynthetic precursor |
| The Organism Strain improvement | -The Science and technology of manipulating and improving microbial strains, in order to enhance their metabolic capacities for biotechnological applications -Essential when setting up a new process or maintaining the competitiveness of an existing one. |
| The Organism Strain improvement How? | - Optimizing enviromental conditions - Optimizng nutrition of microorganism - Mutagenesis |
| The Organism Strain improvement induction | -Usage of constitutive mutants - Supplement of an inducer in the medium |
| The Organism Strain improvement inhibition/ repression | -Avoid build-up of inhibitor/repressor -Find mutants lacking inhibition/repression control |
| The Organism Natural strain improvement | -Transduction -Transformation -Conjugation |
| The Organism Strain Maintainance Why in house collection? | -Source material for R & D -Strain preservation during screening and optimisation -Starter cultures for production |
| The Organism Strain Maintainance Storage Methods | -Lyophilisation (freeze dried stocks) -Glycerol suspensions at –80oC to -196oC -Freeze onto cryobeads -Agar slope cultures overlaid with mineral oil and stored at –20 30 |
| The Industrial Media Typical Medium Ingredients: | - N, C, P sources - Trace elements- vitamin, salt -Selective agents- antibiotic , light, phenol, -pH buffer system- color indicators |
| The Industrial Media What Does the Medium Need to Do? | Supply raw materials for growth and product formation Stoichiometry may help predict these Ingredients in the right form and conc. to direct the bioprocess to the right product and acceptable yields, titres.. May contain metabolic poisons etc. |
| The Industrial Media What Does the Medium Need to Do? cause no problem with: | - Preparation and sterilisation - Agitation and aeration - Downstream processing |
| The Industrial Media What Does the Medium Need to Do? Ingredients must have an acceptable: | - Availability - Reliability - Cost (The costs of carbohydrates represents up to 50-70% of the net sales value of the Fermentation Industry’s products) |
| The Industrial Media Carbon Sources | -Major components (Building blocks for growth and product formation, Energy source) -Easily used carbon sources give fast growth but can depress the formation of some products - Cheap and widely avilable - may also supply nitrogen and growth factir |
| The Industrial Media Carbon Sources Lactose | -Pure or whey derived product -Liquid whey Cheap Uneconomic to transport Used for biomass and alcohol production |
| The Industrial Media Carbon Sources Glucose | - Solid or syrup (starch derived) -Readily used by almost all organisms - Catabolite repression can cause problems (Craptree Effect) |
| The Industrial Media Carbon Sources Vegetable Oils | -Olive, cotton seed, linseed, soya bean etc. -High energy sources (calorific value = 2.4 x glucose). Increased oxygen requirement Increased heat generation -Antifoam properties |
| The Industrial Media Nitrogen Sources | - Ammonium salts - Ammonia - Nitrates Yeasts cannot assimilate nitrates -Proteins – completely or partially hydrolysed Some organisms prefer peptides to amino acids |
| The Industrial Media Vitamin Sources | -Pure sources expensive -Often supplied by crude ingredients: Pharmamedia Cornsteep powder Distillers solubles Malt sprouts |
| The Industrial Media Mineral Sources (and trace elementa) | -Found in crude ingredients. -Use inorganic sources if necessary - Inorganic phosphates. Also act as buffering agents Excessive levels depress secondary metabolite formation |
| The Industrial Media Precursor | Help direct metabolism and improve yields |
| The Industrial Media Inhibitors | Used to redirect the cells metabolism towards the target product and reduce formation of other metabolic intermediates |
| The Industrial Media Antifoams what cause foam to form? | - Aeration - Certain surface active compounds in the medium or in the product |
| The Industrial Media Antifoams Problems caused by foam: | - Sub-optimal fermentation Poor mixing Cells separated from medium Product denatured - Contamination - Loss of bioprocessor contents |
| The Industrial Media Antifoams Dealing with foaming problems | - Avoid foam formation Choice of medium Modify process - Use a chemical antifoam - Use a mechanical foam breaker |
| The Industrial Media Antifoams | - Effective - Sterilisable - Non toxic - No interference with downstram processing - Economical |
| The Industrial Media Antifoams Fatty acids and derivatives (vegetable oils) | - Metabolisable - Cheaper than Silicones - Less persistant Foam may reoccur : more has to be added. Used up before downstream processing |
| The Industrial Media Antifoams Silicones | -Non metabolisable -More expensive that Fatty acids and derivatives -More persistant Less needed. Could interfere with downstream processing -Often formulated with a metabolisable oil “carrier” |
| The Industrial Media Antifoams Mechanical Foam Breakers | -Fast spinning discs or cones just above the medium surface -Fling foam against the side of the bioprocessor and break the bubbles -Can be used with or without antifoams |
| The Process Strain Selection & Development Product formation | - Natural property (alcohols, enzymes) - Enhanced natural property: dedicated modification to increase/ introduce desired product formation - Recombinant property: introduction of foreign DNA to create genetically modified strain secreting the product |
| The Process Strain Selection & Development Limitations | -Nutritional requirements -Metabolic control -Shear sensitivity -Morphology -O2 requirements -Genetic stability -Metabolic by-products -Temperature optima -Viscosity |
| The Process Strain Selection & Development Advantages | - High growth rate and production rate - easy processing |
| The Process Fermentation medium / Raw Materials | Source of carbon, nitrogen, phosphorous, trace elements, growth factors, water, etc. Design factors: metabolism of micro-organism, cost, availability, stability, … Complex media versus minimal media |
| The Process Fermentation medium / Raw Materials High energy crops, | e.g., corn, maize, cereals, sugar cane, beets (starch, glucose) Pretreatment Waste products from e.g. sugar industry (molasses) |
| The Process Fermentation medium / Raw Materials Low energy plant waste | e.g., wood chips, straw, waste paper, bagasse lignocellulosic material (10-35 w/w % lignin, 15-55 w/w % cellulose, 25-58 w/w % hemicellulose) Pretreatment |
| The Process Fermentation Process Selection and design considerations: | - O2 supply -efficient aeration and agitation (~ oxygen transfer rate [kg O2 /m³h]) -important energy cost -Shear sensitivity of cells -Efficient cleaning (CIP) and sterilization (SIP) -Control: temperature, pH -Foam production -Mode of operation |
| The Process Fermentation Process Modes of Operation | Batch: Large flexibility; economical; low control Fed-batch: Controlled growth/product formation rate Continuous: Highest productivity Sensitive for contaminations and genetic alterations in production strain; process control |
| Food Fermented Food | Foods that have been subjected to the action of MO or enzymes, to bring about a desirable change Numerous food products owe their characteristics to the fermentative activities of MO. Originated thousands of years ago when MO contaminated local foods. |
| Food Fermented Food biological ennoblement | a term that describe the nutritional benefits of fermented foods. |
| Food Fermented Food Properties | - Enhanced preservation -E nhanced nutrition - Enhanced functionality - Enhancement of organoleptic properties - Uniqueness - Economic value |
| Food- Potential hazards of fermented food | - Pathogens: viruses, Bacteria ,parasites - Microbial spoilage - Toxins: mycotoxins,bacterial toxins, biogenic amines |
| Food- Potential hazards of fermented food Mycotoxins | -Secondary metabolites from filamentous fungi - Causing toxicity in low concentrations -Primary sources: agricultural crops, spices, fruits “carry-over” effect from animal-derived food (milk, meat) |
| Food- Potential hazards of fermented food Primary Contamination | Direct Contamination: Direct consumption of the Mycotoxins (bad hygene in the production) Indirect Contamination: Consumption of a product that was exposed to the toxins ( raw materials used for the process are contaminated) |
| Food- Potential hazards of fermented food Secondary Contamination | Consumption of a product that its origin from animal that was exposed to the toxins (like eggs or honey) |
| Food- Potential hazards of fermented food Carry Over | toxic transports from one food to another (called crosscontamination) |
| Food Potential hazards of fermented food Factors ensuring food preservation: salting: | increase of osmotic pressure |
| Food Potential hazards of fermented food Factors ensuring food preservation: Acidification: | -lower pH, denature proteins -Great majority of pathogenic/spoilage MO are neutrophilic (pH 5-9) -pH drop down (disruption of cell pH) → organic acid cross cell membrane → metabolic inhibition -No production of enterotoxin at low pH and 10% NaCl |
| Food Potential hazards of fermented food Production of antimicrobial agents | - Organic acids, - CO2 (growth of microaerophilic/ anaerobic MO) - H2O2 - Diacetyl - Ethanol - Antibiotics - Bacteriocin- producers |
| Food Potential hazards of fermented food Safety is supported by: | -Quality of raw material; quality of feed -Correct/optimal conditions for fermentation -Fermentation with starter cultures -GRAS cultures (fungi, LAB) -Hygiene during production, preparation, storage/ HACCP, packaging -pasteurization, sterilisation |
| Food Starter Culture | -Living microorganisms of defined combination that are used for the fermentation of raw materials - applied to bring out specific changes in the chemical composition and the sensorial properties of the substrate |
| Food Starter Culture Properties | Harmless/positive effects on consumers, no formation of harmful metabolites process with high reproducibility and reliable product quality Protect against food spoiling Cheap production Typical for the product (special flavor) Easily detectable |
| Food Starter Culture- Screening and strain identification Tools for identification | - Sequencing of rRNA (16S, 23S) - Ribotyping - DNA- probes - PCR - DGGE (denaturating gradient gel electrophoresis) |
| Food Starter Culture- Screening and strain identification Applications | - Analysis of the fermentative flora - Monitoring of specific starter strains and species - Detection of new strains and speciesFood |
| Food Alcoholic fermentation with yeast | - Glucose is converted via the glycolysis to pyruvate - Pyruvate dehydrogenase and alcohol dehydrogenase convert pyruvate to ethanol and CO2 |
| Food Beer production with yeast Structure of a barley grain | endosperm cell: 3 layers of cell walls: inner wall: ᵦ- Glucan Outer wall: Hemicellulosic pentosans +ᵦ- Glucan protein. inside the cell there are starch granules (65% of the cell) |
| Food Beer production with yeast | 1. Malting 2. Mashing and wort preparation 3. Fermentation 4. Post Fermentation 5. Clarification, carbonation, Packaging |
| Food Beer production with yeast Malting | The partial germination of cereal grain for 6–9 days to form malt. Primary beer ingredient, contains mostly starch, some protein and hydrolytic enzymes. Malted barley is predominantly used, but beers are also made with malted wheat. |
| Food Beer production with yeast Malting Reasons for malting: | - Development of the flavor - Development of the color (melanoidin compounds) - Arresting the enzyme activity |
| Food Beer production with yeast Malting Reasons for malting: | - Starch hydrolysis: convert malt to fermentable sugars - ᵦ‐Glucan hydrolysis: Degradation by malt endo‐ ᵦ ‐ glucanases (Prevention of filtration problems) - Protein hydrolysis: Protease degrade wall and matrix proteins of endosperm cells |
| Food Beer production with yeast Mashing and wort preparation | production of the fermentation medium (wort).Contains sugars, AA and nutrients, prepared by solubilizing malt usinig hydrolytic enzymes. The wort is sterilized; hops added for their bitter flavor and characteristic aroma. wort preparation takes 5–8 h. |
| Food Beer production with yeast Fermentation | - In large, closed stainless steel vessels - Addition of yeast - Flocculation of yeasts occurs when fermentable sugars are depleted → end of fermentation |
| Food Beer production with yeast The yeast | - Effective in taking up nutrients from the wort - Great tolerance to alcohol - High fermentation rate Yeast Management Stock culture + recovered yeast from former fermentation (5‐10 times) Inoculation (=Pitching) in the fermenter |
| Food Beer production with yeast Top- fermented beer | -Even distribution of yeast -S. cerevisiae -18 -25 °C - 2-4 days - Stout, Ale, Wheat beer (types) |
| Food Beer production with yeast Bottom fermented beer | - Sedimentation of Yeast - S.Pastorianus - 6 -12 °C -7 days -Lager, Bock (types) |
| Food Beer production with yeast Post Fermentation | Green beer from 1st fermentation process contains yeasts, other MO, insoluble and non-dissolved materials |
| Food Beer production with yeast Post Fermentation: Maturation | - Ale beer: green beer → addition of sugar → 2nd fermentation (12°C to 18°C ,up to 7 days) - Lager beer: in closed tanks (0°C, three months); special variation is addition of worth from krausening → CO2 is trapped |
| Food Beer production with yeast Clarification, carbonation, Packaging | most beers are filtrated to remove yeasts/ residue of yeasts; addition of fining agents CO2 preserves the beer by reducing pH and oxidation-reduction potential →via a secondary fermentation, or by directly adding CO2. packaging/(pasteurization) |
| Food Beer production with yeast- low(non) alcoholic beer | - Removal of the alcohol from conventionally produced beer by vacuum evaporation dialysis reverse osmosis - Fermentation may be performed in such a way as to restrict ethanol production |
| Food Beer production with yeast- low(non) alcoholic beer categories | - low‐alcohol, containing up to 1.2% (v/v)ethanol - dealcoholized, 0.05–0.5% (v/v) ethanol - alcohol‐free, with less than 0.05% (v/v) ethanol |
| Food Beer production with yeast- microbial aspects | - Non-typical yeast: off-flavours and turbidity - Lactic acid bacteria: silky turbidity, buttery, acid off-flavours, viscosity (extracellular slime formation) - others: contamination of the cold wort they form off-flavours that disturbing final tast. |
| Food Beer production with yeast- Strain Improvement | - yeasts used for beer brewing are very well investigated - breweries have their own starter culture → strain improvement programs - strains have different properties in growth, flavor production, fermentation and flocculation behavior |
| Food Wine production with yeast The Yeast | Two types of yeast are responsible for wine production: -Wild type yeast on grapes-inactivated with SO2 at a concentration of 100 ppm -Cultivated Saccharomyces ellipsoideus which are added to the fruit juice- not affected by this concentration of SO2 |
| Food Wine production with yeast Characteristics of a wine starter culture | - Tolerance to: alcohol, high sugar, musts, SO2, low and high temperatures, high pressure - Production of small amounts of : acetic acid, acetaldehyde, H2S, mercaptans, diacetyl, SO2 and higher alcohols |
| Food Wine production with yeast Crushing and Maceration white wines | -Destemmed grapes are pressed -Juice is separated and clarified from the seeds, skins, and pulp after 3‐8h +/‐ SO2 to control wild flora, and as AO to control browning -Juice is transferred to tanks → fermentation starts naturally or induced by yeasts |
| Food Wine production with yeast Crushing and Maceration red wines | - pressed grape‐juice + skin transferred to open tanks - pre‐fermentation for several days‐ naturally or by addition of strain - purple pigments and phenolic compounds, tannins are extracted → color, taste - time/ temperature determines type of wine |
| Food Wine production with yeast Fermentation | -Traditionally in large open wooden tanks, today enclosed stainless steel tanks -Before fermentation different additives may be added ( deacidification, addition of sucrose) -fermentation complete when all/ most of the sugars are depleted |
| Food Wine production with yeast Fermentation → exothermic reaction: | temp. increase of the fermented juice up to 10°C is possible |
| Food Wine production with yeast Fermentation white wines | at 10‐18°C , 1 – 4 weeks (→ slower fermentation; retention of volatile flavor compounds, higher ethanol concentration, less sugar remaining) |
| Food Wine production with yeast Fermentation Red wines | at 20‐30°C, 3 – 5 days. pomace is pressed from skins (press juice) |
| Food Wine production with yeast Malo lactic Fermentation | Typical wine: a pH of 3.3‐3.6; if pH is low a natural deacidifiction by LAB, pH about 0.3‐0.5 higher→ wine tastes softer -Duration 2‐4 weeks -a greater microbial stability, less spoilage by other MO due to bacteriocin production and diminished nutrients |
| Food Wine production with yeast Racking | - Ageing: from several years to few weeks, in oak barrels, stainless steel, and in bottles, or a combination of all - Clarification: application of several processes including addition of fining agents, centrifugation , membrane filtration - Bottling |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria | -Food preservation in which milk protein and fat are conc., whey is removed and milk sugar (lactose) is fermented into lactic acid by LAB -preservative property arises from combined effects of acidification, dehydration and salt addition |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria conversion of milk into cheese | coagulation of proteins → acidification → formation of casein gel enzyme chymosin → hydrolyzing κ-casein calcium mediated sediment, casein traps fat and few whey acidification (pH 6) +heat (>85°C) → whey denatures, precipitate of whey, casein, fat . |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Milk treatment. | - heat-treatment (73 °C, 15 s), destroy pathogen, reduce microbial numbers - The milk may also be standardized (increase /reduction of the fat content, adjustment of the casein/fat ratio) -traditionaly, raw-milk cheeses heat treatment is not applied. |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Backslopping: | inoculation of the raw material with a small quantity of whey from a previously performed successful fermentation |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Starter-culture addition. | - Large-scale processing relies on using defined, commercially available starters, depending on the recipe - For traditional cheeses, a natural fermentation is often used |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Starter Culture | - Mesophile LAB: cheeses where temp. of 20-40°C - Thermophile LAB: cheeses where temp. of 30-50°C - Acidification lactose → lactat - Texture development during ripening; interactions of milk constituents, LAB, 2ndary flora, enzymes released ... |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Propionibacteria | -P. freudenreichii, used in Swiss cheese technology -Convert lactate via propionate- pathway into propionate, acetate, ATP and CO2 → eye formation - Lipolytic- and proteolytic activity (formation of proline) |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Moulds and Yeast (secondary flora) | 1. P. camenberti, P. roqueforti 2. Geotirichum candidum (“ the milk mould”) 3. Yeasts |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Moulds and Yeast (secondary flora) P. camenberti, P. roqueforti | - On mould ripened cheese, characteristic colour from dark blue to light green/ white - Growth at cold storage temp (4-10°C) and wide pH range (4-6) and high salt level, microaerophilic growing |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Moulds and Yeast (secondary flora) Geotirichum candidum (“ the milk mould”) | - Often used with P. camenberti - Fine, short mycelia on surface of mould-ripened cheese but also a yeast-like appearance referred to as “toad-skin” (e.g. Quargel) - Strict aerob, quickly growing with synergistic effect on the growth of P. camenberti |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Moulds and Yeast (secondary flora) Yeasts | micro flora for many surface-ripened cheeses (red smear, washed rind); colonize surface at an early stage, grow in 4% salt, strong neutralizing activity by metabolizing lactate, proteolytic and lipolytic acitivity |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Smear-cultures complex (secondary flora) | Population of corynebacteria, micorcocci, moulds and yeasts. moulds and yeast degrade lactate, bacteria responsible for the red-orange-yellow colour and the odour of surface smear. neutral pH for rapid growth, salt-tolerant (role in ripening process) |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Smear-cultures complex (secondary flora) | -MO on surface and in the matrix modify texture&flavour -Proteases release: breakdown casein→flavours of AA -Lipases release: lipolysis of milk fats→free fatty acids, other flavours -Lactate degradation: pH decrease→MO inhibited and rapid proteolysis |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Coagulation | Modifications on the milk protein complex occur under defined conditions of temperature and by action of a coagulant agent→ change the physical aspect of milk from liquid to a jelly-like mass |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Cutting the coagulum | Cut the coagulum with appropriate knives or wires, into curd → particles of a defined size, e.g. 1–2 cm |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Heating or cooking the curds | -Heating at 37–45 °C → Affects the rate at which whey is expelled from the curd particles and the growth of the starter microorganisms -During heating, the curds and whey are often stirred to maintain the curd in the form of separate particles |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Whey removal | When the curd particles have firmed and the correct acid development have taken place, the whey is removed allowing the curd particles to mat together |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Milling the curd | - When the curd has reached the desired texture, it is broken up into small pieces to enable it to be salted evenly - Can be done by hand or mechanically -Salting → to enhance the taste of the curd and to increase its safety and shelf life |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Ripening | -Periods from 15 days to years -Crucial for the development of aroma and flavour -The action of the many enzymes released by LAB -Proteolysis: The proteins is broken down from casein to peptides and amino acids. Temperature and humidity controlled |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Primary proteolysis | - Changes in β-, γ-, α-casein-peptides, and other minor proteins - Leads to the formation of large water-insoluble peptides and smaller water-soluble peptides |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria Secondary proteolysis | oProducts include those peptides, proteins and amino acids soluble in the aqueous phase of cheese and are extractable as the water-soluble nitrogen (WSN) fraction. |
| Food Cheese production with lactic acid bacteria and propionic acid bacteria water-soluble nitrogen (WSN) | - The WSN fraction is a complex mixture of large, medium, and small peptides and amino acids. These components result from the action of milk clotting enzymes, milk proteases, starter LAB and contaminating microorganisms. |
| Food Phylum Fungi | - typical eukaryotic cell with cell wall - production of spores - ubiquitous habitats (terrestric and aquatic) - parasitic life‐form - cell wall contains chitin (polymer of N‐acetylglucosamin) - chemoorganotroph |
| Food Fungi as food - White Mushroom Cultivation Substrate | horse dung chicken dung, gypsum, dry straw |
| Food Fungi as food - White Mushroom Cultivation Solid state fermentation | Phase 1: Reduction of the C/N ratio from 30:1 to 17:1 Phase 2: - Pasteurisation at 57 to 58°C - Fermentation at 45°C for optimal substrate production |
| Food Fungi as food - White Mushroom Cultivation Cultivation | Pure culture inoculation Vegetative phase: 24°C, 14 days Coverage with earth: induction of generative phase Generative phase 16°C: building fruiting bodies 1st harvest: 50% total yield Vegetative phase 2nd harvest: 30% total yield |
| Food Fungi as food - Oyster Mushroom Cultivation Substrate | -Crop straw, corn cob, rice straw, cotton waste - To avoid the growth of other microorganisms (Trichoderma, Aspergillus, Fusarium) substrate is sterilized or pasteurized - Pure culture inoculation with 2-4% of the substrate |
| Food Fungi as food - Oyster Mushroom Cultivation phases of composting | - 1st wild - 2nd controlled to aim pasteurization of substrate, killing insect pests, fungal pathogens, viruses; toxic ammonium of compost is metabolized by thermophilic bacteria |
| Food Fungi as food - Oyster Mushroom Cultivation Cultivation Phase | ocultivation phase in plastic bags (20-30 kg) at a temperature of 24-26°C and a CO2 content of 15 to 25% for 16 to 23 days |
| Food Fungi as food - Oyster Mushroom Cultivation Fruiting body production | -Substrate bags contain 15 to 20 mm rips where fruiting bodies grow out -Optimal conditions for production are 15 to 24°C , 85-95% humidity, CO2 content below 600 ppm, illumination of 150 lux for a minimum of 8 h -Total yield of 17-20% of used substrate |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents | Some MO’s produce exopolysaccharides in the form of discrete capsules or as soluble slimes located outside the cell |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents Functions: | - Protect the microorganism against desiccation - Act as a barrier to viruses and chemical agents - Aid attachment to surfaces - Provide carbon and energy reserves |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents Application: | Replace traditional higher plant and algal polysaccharides (starch, alginate, carrageenan, gum arabic...) as thickeners and stabilizers in numerous food and non-food applications |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents Alginate | - linear heteropolymers of L-guluronic acid and D-mannuronic acid, which contain O-acetyl groups. - Formed by Pseudomonas species and Azotobacter vinlandii - Application: e.g. Sizing Agent - Paper Industry |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents Cellulose | - ᵦ-1,4 glucan - formed by strains of Acetobacter xylinum - Can be produced in surface or submerged culture - Application: e.g. Temporary artificial skin following skin surgery or skin burns |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents Chitin | - N-acetylglucosamine residues, and its deacylated derivative - Cell wall components of fungi - Commercial preparation from shellfish wastes - Application: e.g Wound dressing |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents Glycan | - Components of yeast cell walls - Produced from S. cerevisiae - Application: e.g. Pharmaceuticals (Cholesterol reduction treatment, wound healing…) |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents Xanthan | Xanthomonas species ~20000 t/yr D- glucose, D-mannose, D-glucuronic acid (molar ratio of 2:2: 1) D-Glucose units are ᵦ-1,4 linked-form the backbone In solution two xanthan molecules form double helix (viscous) Shear forces cause parallel orientation |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents-Xanthan Key characteristics | -Xanthan Solutions have higher viscosity than other gums at the same conc. -Translucence -Compatibility with acids, bases and salts -Stability at ambient temperature -Pseudoplastic rheological behaviour -Interacts synergistically with other polymers |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents-Xanthan Application: | ~ 60% is used in non-food application Stabilizer for paint emulsions Carrier for fertilizers and herbicides A thickener for textile dyes |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents-Xanthan Baking poducts | -To improve texture -High crumb strength -Increases volume (gas retention) -Moisture retention -Improves flavor and sensory characteristics -Helps to extend shelf-life + freeze-thaw stability of wheat-flour pastes, patisserie and pie fillings |
| Applied Fermentation Technology Primary and Secondary Metabolites- Thickening agents-Xanthan Dressings | produces very stable emulsions in the production of oil-based and non-oil-based dressings (sauces and ketchups with long shelf-life and flavor release) |
| Technical alcohols Industrial Production of Ethanol | Annual world production of ethanol over 30 billion litres ~70% is produced by fermentation, -Rest is produced by the catalytic hydration of ethylene Applications: Almost 12% beverage alcohol 20% is for various industrial uses 68% is fuel ethanol |
| Technical alcohols Industrial Production of Ethanol Microorganism | oS. cerevisae for hexose oCandida sp. for lactose or pentose oBacteria (e.g. Thermoanaerobacter ethanolicus) oThermostable amylases (glucoamylases) |
| Technical Acids Citric Acid | - 70% used for conservation in food- and beverage industry - 20% used in pharmaceutical industry for blood preservation, production of tablets, cosmetic preparations - 10% used in chemical industry as anti foam agent, additive for washing agents |
| Technical Acids Citric Acid Application | oAcidulant in food, confectionary, and beverage (75%) oPharmaceutical (10%), e.g. soluble aspirin preparation oIndustrial (15%): complexes with metals such as iron and copper to be stabilizer of oil and fats. |
| Technical Acids Citric Acid production | - Produced by many mold fungi (Aspergillus, Penicillium) and yeast (Candida) oSynthesis via the citric acid cycle from oxalic acetate and Acetyl-CoA by citrate synthase oProduced as secondary metabolite at pH 2 |
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