1 / 12

Regulation/Deregulation or Production Cultures

Regulation/Deregulation or Production Cultures. Regulation. natural process (survival) prevents overproduction of enzymes and products deregulation necessary to be commercially viable. Environmental manipulations. nutrient imbalance: citric acid production with fungi by limiting Fe, Mn

judah
Download Presentation

Regulation/Deregulation or Production Cultures

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Regulation/Deregulationor Production Cultures

  2. Regulation • natural process (survival) • prevents overproduction of enzymes and products • deregulation necessary to be commercially viable

  3. Environmental manipulations • nutrient imbalance: citric acid production with fungi by limiting Fe, Mn • inducers or substrate analogs • bisulfite in yeast fermentation produces glycerol at expense of ethanol

  4. environmental manipulations • catabolite repression (glucose effect) S1 S2 repression or inhibition

  5. A B C D enz A feedback inhibition or repression environmental manipulations • end product removal • eg. assume enz A is desired product • remove end product D

  6. environmental manipulations • alter cell permeability • eg. glutamic acid production with Micrococcus or Corynebacterium • limit biotin to 1-5 μg/L • 15 μg/L will stop excretion • yeast treated with surfactants

  7. genetic manipulation: limit accumulation of end product enzC enzD enzA enzB A B C D E feedback regulation • C is desired product • auxotrophic mutant lacking enzC • E must be added to medium at low levels for growth • C accumulates as culture is deregulated • eg. Bacillus subtilis 16 g/L L-citrulline • Corynebacterium glutamincum 26 g/L L-ornithine

  8. isolation of feedbackresistant mutants enzA A B C D E feedback regulation • E is desired product (eg. amino acid) • analog E' also represses enzA but E' cannot be used for growth • mutate cells and grow with E' in excess • deregulated cells do not grow • growing cells can synthesize E in presence of E' (de-regulated)

  9. branched pathway A B C D often by decreasing D, C will be overproduced

  10. aspartate aspartokinase aspartyl phosphate aspartate semi-aldehyde homoserine dehydrogenase concerted feedback inhibition homoserine lysine methionine threonine isoleucine Corynebacterium glutamicum: 50 g/L L-lysine

  11. mutation and selection • mutagens • ionizing radiation, X-rays, γ-rays • non-ionizing, UV • chemical mutagens • base analogues • nitrous acid • hydroxylamine • diethylsulfonate (DES) • nitrosyl guanidine (NTG)

  12. alternatives • protoplast fusion • gene amplification • recombinant DNA

More Related