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Microbialbiotechnologyinthelaboratoryandinpractce
whicharehermeticallyclosedmetaland/orglassvessels
(laboratoryfermenters)thatallowfullcontrolofthegrowthand
productionofproductsbymicroorganisms.Onalaboratoryscale,
fermentersrangingfromseveraldozenmillilitrestoseveraldozen
litresareused.Intheindustry,bioreactorsofeven200thousand
litresormore,areused.Inthelaboratory,atthestageofinoculum
multiplication,glassflasksofuptoseverallitresarealsoused
forsubmergedcultivation.Inbiotechnologicalprocesses,apart
frommicroorganismsslowlysuspendedinthemedium,cells
“trapped”ingelsareoftenused.Theuseofimmobilisedcultures
allowsfortheiruseinafeworevenseveralproductioncycles,
whichsignificantlyreducesthecostofthetechnologicalprocess.
Thecultureofmicroorganismsinaerobicconditionsinliquid
mediacanbedividedintothreebasictypes:batch,fed-batchwith
continuousdosingofmediumandcontinuousculture.
103010Batchculture
Batchcultureisaclosedsystem.Itconsistsofpreparingasterile
culturemediumwithaddedinoculumandconductingthe
cultureinafermenterforaspecificperiodoftime.Changesin
theamountofmicrobialbiomassareobservedfromtheonsetof
incubation(Figure1.3.1).
Microbialgrowthisdescribedthrough6stages.Duringthe
stagnationphase(lag-phase)nobiomassgrowthisobserved;
thistimeisusedbythemicroorganismstoadapttothenew
34
Fig0103010Example
ofthebatchculture
ofmicroorganismsin
fime.