1 / 10

Propionic acid Bacteria Enrichment

Propionic acid Bacteria Enrichment. Bruno Fonseca Hopkins Microbiology Course 2010 Monterey , CA, USA .

ailani
Download Presentation

Propionic acid Bacteria Enrichment

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. PropionicacidBacteriaEnrichment Bruno Fonseca HopkinsMicrobiologyCourse 2010 Monterey, CA, USA

  2. Propionic acid has numerous applications in various food and chemical industries, and is mainly used as a mold inhibitor for animal feeds and as a preservative for foods such as cheeses and baked goods. • Propionic acid is produced mainly by Propionibacterium, but this isn’t the only genera that has this ability: • Propionibacteriumare slow-growing, non-sporeforming, rod-shaped, Gram-positive, anaerobic heterotrophic bacteria. • These microorganisms usually possess catalase. • Ferment lactate and produce acetate, propionate and CO2. • If pH value is below 4.5 there is practically no growth • Clostridium • Veillonella • Selenomonas

  3. First observed in the cheese manufacture, dating back to the beginning of the nineteenth century. • Propionicacid is what partly gives Swiss cheese its characteristic flavor and the CO2 is what produces its characteristic holes. • Propionibacteriumhave been granted GRAS (Generally Recognized As Safe) status by FDA. • However, certain species of Propionibacteriumare known for causing infections including the common skin disease acne vulgaris (caused by P. acnes). • van Niel named some species of Propionibacterium.

  4. Day 1 • Inoculum: • Swiss-cheese • Media: • 40 gr Sodium-lactate • 5 gr Yeast extract • Selective technique: • Lactate as the major carbon/electron source • Anaerobic growth (screw capped tubes gently bubbled with CO2) • Incubate at 30 ºC

  5. 2 days later … • Streakedthemilk-whitegrowthinto a lactate-CaCO3agarplate • Incubatedat 30ºC inananaerobicjar

  6. 1 week later … Brownish-redcoloredcolonies Probablydue to having a cytochromesystem CatalaseActivitytest: Catalase 2H2O2 2H2O + O2 Production of O2 Bubbles

  7. Looking at them under the microscope… Smallnon-motilerod-shappedbacteria

  8. Propionic acid formation Dicarboxylicacidpathway: NAD+ Lactate LactateDehydrogenase NADH methylmalonyl-CoAmutase Vitamin B12 Succinate

  9. Propionic acid formation Acrylatepathway: CoA-SH CoA-SH ThispathwayoccursnamelyinClostridiumpropionicum

  10. Propionic acid formation Acrylatepathway:

More Related