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Methodsofscreening,culturing,improvementandstorageofmicroorganisms...
3.
Quantitativedeterminationofsubstratesincultures:after
6daysofincubation,centrifugealltestedculturesystems
(6,000×g,15min),filterthesupernatantsthrough0.2Pm
porediameterfiltersandthendeterminethecontentof
testedacidsandvitaminsbyliquidchromatography
(accordingtothesamemethodasthestandardcurves).
InthecaseofvitaminB
12
biosynthesisanalysis,the
bacterialculturesareadditionallyincubated20min.at
80°C,thenhomogenisedusingamechanicaldisintegrator,
thenusingthesameprocedureasusedforthesamplesfor
quantitativedeterminationoforganicacids.
Analysisofresults
Onthebasisofthequantitativeresultsobtainedfromthe
chromatographicanalysis,drawconclusionsconcerningthe
influenceofoxygencontentandthecompositionofthegrowth
mediumontheproductionyieldofvitaminB12andorganicacids
bytheP.freudenreichiissp.shermaniistrain.
1050Fungalprotoplasts:release,propertes
andapplicaton
INTRODUCTION
Theterm“protoplast”isusedtodescribeabacterial,fungalor
plantcellcompletelydevoidofacellwall,buthasacellmembrane
astheonlyexternalshield.Theterm“spheroplast”,ontheother
hand,referstoacellonthesurfaceofwhichfragmentsofthecell
wallarepresent.Protoplastsandspheroplastsdonotoccurunder
naturalconditions.Theexceptionsarestrains(thatarepathogenic
toinsects)ofcertainmicrofungioftheEntomophthoromycotina
subtype,Zoopagomycota(formerlyZygomycota),where
protoplasticandspheroplasticcellsarepresentduringoneofthe
stagesofdevelopment.Additionaldataonthisgroupoffungi
areprovidedinSection5.13.Comparedtothebaselinecells,
thephysiologicalandbiochemicalpropertiesofprotoplasts
aresimilar.TheexceptionsaretherateofDNAsynthesis
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