Propionic
Download
1 / 10

Propionic acid Bacteria Enrichment - PowerPoint PPT Presentation


  • 721 Views
  • Uploaded on

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

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Propionic acid Bacteria Enrichment' - magda


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

PropionicacidBacteriaEnrichment

Bruno Fonseca

HopkinsMicrobiologyCourse 2010

Monterey, CA, USA


  • 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


  • 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.


Day beginning of the nineteenth century. 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


2 days later … beginning of the nineteenth century.

  • Streakedthemilk-whitegrowthinto a lactate-CaCO3agarplate

  • Incubatedat 30ºC inananaerobicjar


1 week later … beginning of the nineteenth century.

Brownish-redcoloredcolonies

Probablydue to having a cytochromesystem

CatalaseActivitytest:

Catalase

2H2O2 2H2O + O2

Production of O2 Bubbles


Looking at them under the microscope… beginning of the nineteenth century.

Smallnon-motilerod-shappedbacteria


Propionic beginning of the nineteenth century. acid formation

Dicarboxylicacidpathway:

NAD+

Lactate

LactateDehydrogenase

NADH

methylmalonyl-CoAmutase

Vitamin B12

Succinate


Propionic beginning of the nineteenth century. acid formation

Acrylatepathway:

CoA-SH

CoA-SH

ThispathwayoccursnamelyinClostridiumpropionicum


Propionic beginning of the nineteenth century. acid formation

Acrylatepathway:


ad