Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Microbial production of solvents


Published on

Industrial production of solvents especially ethanol

Published in: Education, Business, Technology
  • Dating direct: ❶❶❶ ❶❶❶
    Are you sure you want to  Yes  No
    Your message goes here
  • Follow the link, new dating source: ❤❤❤ ❤❤❤
    Are you sure you want to  Yes  No
    Your message goes here

Microbial production of solvents

  2. 2. SOLVENT Liquid that dissolves any kind of solute. Common solvents * Ethanol * Acetone * Butyl alcohol * Glycerol etc..
  3. 3. COMMON USES  Dry cleaning (tetrachloroethylene)  Paint thinner (toluene, turpentine)  Nail polish removers & glue solvents( acetone, ethyl acetate, methyl acetate)  Spot removers(hexane, petrol ether)  Detergents( citrus terpenes)  Perfumes (ethanol) &  Chemical synthesis..
  4. 4. Ethanol production Petrochemical – hydration of ethylene Biological – fermenting sugars with yeast Chemical ethylene hydration :  Raw materials: petrochemical feedstocks  Process : acid- catalyzed hydration of ethylene  Reaction : C₂H₄ + H₂O CH₃CH₂OH  Catalyst : phosphoric acid – adsorbed onto a porous support(diatomaceous earth/charcoal)
  5. 5. Biological fermentation : Dry mill process or wet mill process. DRY MILL PROCESS Overall reaction involved  fermentation of starch portion of corn into sugar  distillation into alcohol
  6. 6. Steps involved in dry mill process SACCHARIFICATION Cooled mash + glyco amylase - Liquefied sugars to fermentable sugars (dextrose) LIQUEFICATION Meal + water +alpha amylase -Cookers (120 -150)˚c & 95˚C – starch is liquefied MILLING Feed stocks passed through Hammer mill - Fine powder ( meal) FERMENTATION Sugars ethanol & CO₂ Continuous flow of mash through several fermenter–fully fermented & leaves the tank Batch process – mash in one fermentor for 48 hrs (beer) before distillation is started yeast
  7. 7. DENATURING Ethanol used for fuel must be denatured or made unfit for human consumption, with a small amount of gasoline (2-5%) This is done at ethanol plant DEHYDRATION Alcohol from top of the column – dehydration system (remaining water removed) Most ethanol plants use molecular sieve to capture last bit of water in the ethanol Alcohol product at this stage (anhydrous ethanol – pure, without water) – 100% proof DISTILLATION Fermented mash(beer)–10% alcohol & all non-fermented solids from corn & yeast cells. Mash – pumped into continuous flow, multi-column distillation system – alcohol Alcohol leaves the top of final column at 96% strength & residue mash (stillage) transferred from base of the column to the co-product processing area
  8. 8. Co- Products Distillers grain : used wet or dry – highly nutritious livestock feed CO₂ : Given off in great quantities during fermentation Many ethanol plants collect ,compress & sell it for use in other industries.  Most ethanol from microbial fermentation-preparation of beverages.  Ethanol production from sugary substrates-expensive than naturally available petroleum.  Microbial conversion of sugar to alcohol is limited by the toxicity of alcohol which cannot accumulate in the fermenter beyond a limit.  The recovery process which involves distillation requires energy input.
  9. 9. Ethanol production by bacteria  Bacteria which can ferment sugar faster than yeast have been found eg. Zygomonas mobilis & Thermophilic Thermobacter ethanolicus.  As sugary substrates are expensive & are used for food, it may be possible to use cellulosic materials & photosynthetic MOs.  Process: 1. Cellulose Sugar 2. Sugar Alcohol Clostridium sp. Zygomonas mobilis (or) Thermobacter ethanolicus
  10. 10.  The anaerobic bacterium Clostridium ljungdahlii, (in commercial chicken wastes) can produce ethanol from single carbon sources including * synthetic gas, * a mixture of CO and H that can be generated from the partial combustion of either fossil fuels or biomass.  If these techniques coupled with genetic engineering techniques - possible to produce cheap ethanol to meet the organic solvents & automative fuel requirements of the world.
  11. 11. Advantages of Z.mobilis over S.cerevisiae  Higher sugar uptake & ethanol uptake  Lower biomass production  Higher ethanol tolerance  Doesn’t require controlled addition of oxygen during the fermentation  Amenability to genetic manipulations Limitations compared to yeast  Difficulties in converting large amount of complex CHO polymers like cellulose, hemicelluloses and starch to ethanol.  Its utilizable substrate range is restricted to glucose, fructose and sucrose.  Its resulting in by-products such as sorbitol, acetoin, glycerol and acetic acid.  Formations of extracellular levan polymer.
  12. 12. ACETONE & BUTYL ALCOHOL  Chaim Weizmann, England in the early part of this century when acetone: production of explosives & butanol: making synthetic rubbers.  N-butanol is used in brake fluids, urea-formaldehyde resins & in lacquers used as protective coatings in automobiles.
  13. 13. Organism: 1. Clostridium acetobutylicum – 1st organism – industrial production of acetone from starch. 2. Clostridium saccharoacetobutylicum – convert molasses into acetone & butanol.  submerged cultures  Substrate: sterile diluted molasses or cooked corn meal.  pH : 7.2  Type of fermentation: anaerobic  By-products : CO₂( preparation of dry ice) & H (fuel)  Product recovery : fractional distillation
  14. 14. GLYCEROL Main uses :  solvent in food colouring agents  Lubricant in toothpastes, candies, cake icings  Cosmetic & pharmaceutical industries  Production of explosives & propellants. Production:  organism : yeast - Saccharomyces cerevisiae or bacteria – Bacillus subtilis
  15. 15. BY R.ABARNA BTH-12-001 THANK YOU