Industrial Microbiology PDF

# Industrial Micro Enhancements of metabolic reactions to produce metabolites of interest to create products. Industrial microbiology has two aspects: - Production of microbial products (fermentation). - Environmental Roles of microbes via biomediation/biodegradation. Microbes they are very goo...

# Industrial Micro Enhancements of metabolic reactions to produce metabolites of interest to create products. Industrial microbiology has two aspects: - Production of microbial products (fermentation). - Environmental Roles of microbes via biomediation/biodegradation. Microbes they are very good at producing large arrays, but they produce these compounds in small amounts that they need for growth. ## Fermentation - The breakdown/re-assembly of biochemicals industrially by organisms under aerobic/anaerobic conditions. - Fermentation is a part of the glycolysis pathway (important process for the regeneration of the living cells). - Nutrients they are oxidized by glycolysis and released electrons reduce NAD+ to NADH. ## Products - Waste products produced in the absence of O2 - They are needed to regenerate NAD in the absence of O2. Pyruvate produced in glycolysis is metabolized to ethanol and carbon dioxide (Alcohol fermentation). $$C_6H_{12}O_6 → 2C_2H_5OH + 2CO_2 + 2ATP$$ ## The type of yeast is known as alcoholic fermentation. - This yeast is used to make alcoholic drinks. ## Anderobic fermentation. - Pistarea drinks (concentrating alcohol from fermentation by distillation). - Wine (fermentation of thellis). - Beer (fermentation of malted grains). ## Beer Brewing Yeast - unicellular fungi which divides asexually by fission and do not produce a true body for sexual reproduction. - Wild yeasts are found on/inside thehus and flowers of plants. - They cause microbial decay of ripe fruits (sugars). - Ethanol production by fermentative yeast may specifically evolved to inhibit bacteria during bacterial competitors within the ripe fruit. ## Alcohol Timeline: - Fruit-based - Alcohol - Mead - Beer (honey) ## Yeast: - The more complex the sugar, the less likely the yeast can use them. - Yeast uses more monosaccharides than trisaccharides. - Brewing yeast can directly digest starch. Instead, during the brewing process - the starches which are present in the barley are broken down into simple sugars through the process called Mashing. The beer flavors are complex and this is due to the changes which occur at the molecular level in raw materials. - Grain - Hops - Yeast - Malt/ - Brewing Stages ## Beer ranges. - 3.1 - 30.1 (ABV). - Beer can be made as Ales/Lagers. - Ales - fermented at hotter temperatures, lagers - colder temperatures. - Different yeast is used for Ales/Lagers. ## Ales: - Chocotastey - Amber - Complex - Pale ales - Stout ## Lagers: - Crisp - Smooth - L. Popular ## Pilsner - Marzen ## Raw Materials: - Main ingredients = Water, gains (mainly malted barely), hops and yeast. - Beers contain 3 - 8% of (v/v) ethanol. - **Water** - Essential ingredient in brewing. - Beer has (90 - 95 H2O). - Added to Malt to create mesh with minerals of water are important for this process. - PH is important in mashing for activity of various enzymes. - Regional water analysis affects beer flavor - Water type depends on the beer being brewed. ## Water Hardness - The amount of dissolved calcium and magnesium in water. Higher levels of these and other minerals make the water hard. - Water softening - reducing concentration of the calcium and magnesium in water. Soft water - ( ↑ [NaCl] Thus less calcium concentration). ## The most common salts used in brewing - Calcium Sulfate (Gypsum) - for a drier, clean finish such as Pilsner Lagers. (↑ Bitterness of the hops, used in IPAs). - Calcium Chloride - Delivers a fuller body and sweeter finish. - Magnesium Sulfate (Epsom salt) - added to brewing water to + sulfate and Mg content. - Mg - critical for yeast metabolism. (Promotes healthy yeast growth and fermentation) ## Hard Water - Dark Beers, Stouts - Dark roasted malt ( ↑ ptt) - Hard water - results in a lower reduction of alkalinity. ## Soft Water - Pale lagers with a good hop character. - If brewed in hard water - end up hard and stringent. ## Malts - Malted grains used for brewing. - Rice, barley, sorghum, wheat, oats, malt, etc. - A source of starch (sugar) = Maltose - It imparts flavor, sweetness and color to the beer. ## Hops - They are added during the boil. - Humulus lupulus family: C.arinaceae - **Hops addition advantage:** - At the beginning - they add bitterness. - At the end - It is for flavor and aroma . - Produces a pungent and aromatic character. - Produces tannins which helps in coagulation of remaining protein. - Contains d-resin, β-lean - gives better flavors to prevent mold - preventive action against foam. - Contains pectin, which is responsible for foam in the beer. - Used to impact additional features. - Foam retention, extra flavor. ## Adjuncts - Rice, maize, corn , oats, wheat, barley. - Chocolate, nuts, spices, extra-sugars. - Unfermented sugars like lactose (added to milk stouts). ## Yeast - Two types: - Ale yeast (Top fermenting). - Lager yeast (Bottom fermenting). Primary metabolites which form during fermentation are: - Ethanol, CO2, Glycerol. ## Flavor is imparted by: - Hops - Yeast secondary metabolites produced by yeast. ## Bad S.M - Aldehyde (green apple). - Diacetyl ( 100 malt dix). - DMS. ## Good S.M. - Clove - Fruity (ester flavor). ## Clarifying Agents - Includes Irish moss, gelden, polyclar. - Precipitate out of the beer during hop protein solids and found in trace amounts in the finished product. # The Brewing Process ## 1. Malting and Milling. - **Milling:** The process of crushing/grinding malt to reduce size and release fermentable sugars. - **Malting:** Converting barley into malt used for brewing. It is the preparation of fermentable mashes from cereal. ## Air Process of Malting: - Getting enzymes which will break down starch (sugar). - Quain's starches are transformed by soaking - germination. - Therefore the adron will become algae and cooked. - It will be ready for fermentation. - **α-amylase** - breaks amylopectin (long) branches of the starches and creates long sugars. - Temperature: 67°C - 73°C ( α-amylase optimum temperature: 60°C -75°C) - **β-amylase** - breaking the α-1,4 glucosidic bonds degrading long - simple sugars - Temperature: 55°C - 66°C ( β-amylase optimum desivity temperature: 67°C - 65°C ). - Grains are steeped for 1-3 days. - Cooled in humid air so they can germinate (3-4 days). - Then dried in a kiln to 17 days. - (Rest period of 3 weeks, bottled grains become malt). ## 2. Mashing and Wort preparation. - **Mashing:** The process of mixing milled malt both water and heating for 2-3 hours in a mash tun. - Enzymes digest starches and liberate sugars. - Most abundant sugars in wort: Maltose, maltotriose, glucose, sucrose, isomaltose. - Other sugars identified: Isomaltose. ## Lauterning: - Refers to the process of separation. - Mash is separated towards wort and residual grain - Residual grain is sparged by running warm water over it to remove the residual sugars. ## How is the wort flavored? - By boiling in a wort kettle. ## Reasons for boiling the wort: - Extraction of hop flavor from hops. - Coagulates remaining protein/partially hydrolyses the protein and helps in the removal of protein. - Deactivates enzymes which were active during the mashing. Causes caramelization of sugar. - Intensifies malolactic reactions between reducing sugars and amino acids - Steralizes and concentrates the wort. ## 3- Yeast fermentation - Wort is cooled. Yeast is added. - Yeast cultures for inoculation are usually recovered from previous fermentation tank by treatment with: - Sodium bisulfite. - Tartaric acid. - Ammonium per sulfate. - To reduce ptt and remove bacterial contamination. - Fermentation: 14 days. - During fermentation, yeast convert sugar into ethanol, CO2 and glycerol. - Also produces diacetyl and secondary metabolites. - After the 14th day, there is no more CO2 formed because the yeast cells not inactive. ## Two main types if yeast used in brewing: - *S. Cerevisiae (Top fermenting yeast) "Ales"* - *S. Pastorianus (Bottom fermenting yeast) "Lagers"* ## 4. Post Fermentation - Beer is stored at 0°C for several weeks - To precipitate of protein, yeast, resin and other undesirable substances occur. - Therefore, beer becomes clear. - Esters are also produced (flavor and aroma). ## After aging (Post-fermentation): - The beer is carbonated with CO2. - The beer is then cooled, sanitized and packed in bottles. ## SAB PROCESS - **Wort production:** 1. **Milling** - The malt is taken to mash tuns and mashed for 2 hours to activate various enzymes. 2. **Lauter tuns** - where malt grains are processed (malt hold wort). 3. **Wort Kettle** - for boiling process; more hops and adjuncts are added. 4. **Whirlpool Kettle** - The wort is added at a rapid velocity so the hops remain at the bottom of the whirlpool. - Then the wort stands for 20 mins - 30 mins for the hops to impart a flavor. - It is spun at a rapid velocity causing it to form a cone (10-20 mins). - Yeast is added for yeast metabolism. 5. **Separation** - It is separated from the pure wort by pumping. - **Fermentation**: - The wort is sent to fermentation cells and placed into large fermentation vessels with cooling jackets. - 12 days (14°C - Black Label 15.8°C) - **Maturation**: - After fermentation, beer is placed in quiller. - **Filtration**: - Kieselguhr candle filters (diatomaceous earth) to clear beer. - Removes any residual yeast and trub. - **Bottles**: - The beer is then transported to a bright beer tank. - The beer is concentrated to the correct volume. - Then Carboned before bottling and capping. # Beer Analysis ## Colour - It can be measured using a spectrophotometer. - SRM (Standard Reference method) is used to measure color intensity. - SRM: 12.7 x DX A430 (LoG) ## International Bitterness Units (IBU) - Bitterness comes from α-acids extracted from the hops during the boil process. - IBU is a result of the type of hops used and when the hops were added. - IBU: 184 x A75nm x 47.