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Methodsofscreening,culturing,improvementandstorageofmicroorganisms...
humanandanimalhealth.Duetotheirhealth-promoting
properties,suchasproductionofvitaminB
12
andB
9
,propionic
acid,trehalose,stimulatingthegrowthofotherprobioticstrains
orsynthesisofbacteriocinswithawiderangeofantimicrobial
activity,theycanactasprobioticpreparationsorvitaminand
proteinsupplements,positivelyafectingthebodybyactinginthe
digestivetract.Inaddition,“classical”bacteriacanincreasethe
bioavailabilityofmanymineralsandproteins,reducesymptoms
oflactoseintoleranceandcounteractintestinalcomplaintssuch
asconstipationanddiarrhoea.Onanindustrialscale,dairy
PropionibacteriumareusedintheproductionofvitaminB
12
,
animalnutritionasafeedandsilageadditive,aswellasinthe
dairy,bakeryandcheeseindustriesbecauseoftheirabilityto
producepropionicandaceticacidandCO
2
asaby-productof
fermentation.Thesepropertiesareparticularlyusefulinthe
productionofhardrennetcheese,fermentedacidifiedproducts
orvegetablesalads.Carbondioxideisresponsible,amongothers,
fortheholeformingprocessinsomecheese,whilepropionicand
aceticacidhavestrongantimicrobialpropertiesandgivethe
productsappropriateorganolepticfeaturesaswellaspreventthe
formationofunpleasantsmellandtaste.
PRACTICALPART
Materialsandmedia
1.
Microorganisms:Propionibacteriumfreudenreichiissp.
shermaniiDSMZ4902.
2.
Media:withyeastextract,caseinmedium,mediumwith
caseinhydrolysate.
3.
Reagents:standardsubstances(vitaminB
12
,lacticacid,
aceticacid,propionicacid),cobaltchloride(CoCl
2
×6H
2
O).
4.
Apparatus:ANOXOMATdeviceforpreparationandculture
ofbacteriainanaerobicandmicroaerophilicatmosphere
(6%O
2
),jarsforcultureofbacteriainanaerobicand
microaerophilicconditions,incubator,rotaryshaker,liquid
chromatographcoupledwithmassspectrometer(LC/MS),
laboratorycentrifuge,mechanicaldisintegrator.
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