Fermentation ii


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Fermentation ii

  1. 1. Lecture ii
  2. 2.  Industrial fermentation is comprised of two main stages · Upstream Processing (USP) · Downstream Processing (DSP)
  3. 3. • Involves all factors and processes leading to and including• the fermentation.• · It consists of three main areas:• PRODUCER MICROORGANISM.• This include processes for• a. obtaining a suitable microorganism• b. strain improvement to increase the productivity and• yield• c. maintenance of strain purity• d. preparation of suitable inoculum• FERMENTATION MEDIA.• FERMENTATION PROCESS.
  4. 4.  It is the collective term for the processes that follows fermentation . a. cell harvesting b. cell disruption c. product purification from cell extracts or the growth medium
  5. 5. • Recovery of cells and/or medium (clarification) – For intracellular enzyme, the cell fraction is required – For extracellular enzymes, the culture medium is required• On an industrial scale, cell/medium separation is almost always performed by centrifugation – Industrial scale centrifuges may be batch, continuous, or continuous with desludging
  6. 6.  Downstream – ‘after the fermentation process’ Primary ‘unit operations’ of Downstream Processing  Cell recovery/removal  Centrifugation  Dewatering  Ultrafiltration  Precipitation  Spray drying
  7. 7.  Dewatering of whole cell fraction (use centrifugation) Dewatering of culture medium or a lysed cell fraction (for recovery of a soluble protein fraction)  S Precipitation  Salting out – addition of a high concentration of a soluble salt (typically ammonium sulphate) causes proteins to aggregate and precipitate  Ultrafiltration  The solution is forced under pressure through a membrane with micropores, which allows water, salts and small molecules to pass but retains large molecules (e.g., proteins)  Spray drying  Requires use of heat to evaporate water – unsuitable for most proteins
  8. 8.  Sonication  Use of high frequency sound waves to disrupt cell walls and membranes  Can be used as continuous lysis method  Better suited to small (lab-scale) operations  Can damage sensitive proteins Pressure cells  Apply apply high pressure to cells; cells fracture as pressure is abruptly released  Readily adapted to large-scale and continuous operations  Industry standard (Manton-Gaulin cell disruptor) Enzymic lysis  Certain enzymes lyse cell walls  Lysozyme for bacteria; chitinase for fungi  Only useful on small laboratory scale
  9. 9.  Adsorption chromatography  Ionexchange chromatography – binding and separation of proteins based on charge-charge interactions  Proteins bind at low ionic strength, and are eluted at high ionic strength + + - - - + + + + + + + + + + + + + + - - + - + - + + + Positively charged Net negatively (anionic) ion charged (cationic) Protein binds to matrix exchange matrix protein at selected pH
  10. 10.  Binding of a protein to a matrix via a protein- specific ligand  Substrate or product analogue  Antibody  Inhibitor analogue  Cofactor/coenzyme Specific protein is eluted by adding reagent which competes with binding
  11. 11. 1. Substrate analogue affinity chromatography Affinity Enzyme ligand +Matrix Spacer arm Active-site-bound enzyme 2. Immunoaffinity chromatography Antibody Protein epitope ligand +Matrix Spacer arm Antibody-bound enzyme
  12. 12. • Also known as ‘size exclusion chromatography’ and ‘gel filtration chromatography’• Separates molecules on the basis of molecular size• Separation is based on the use of a porous matrix. Small molecules penetrate into the matrix more, and their path length of elution is longer.• Large molecules appear first, smaller molecules later
  13. 13. Large protein Small proteinShort path length Longer path length
  14. 14. 1. Enzyme preparations for animal feed supplementation (e.g., phytase) are not purified2. Enzymes for industrial use may be partially purified (e.g., amylase for starch industry)3. Enzymes for analytical use (e.g., glucose oxidase) and pharmaceutical proteins (e.g., TPA) are very highly purified