產(chǎn)普魯蘭多糖出芽短梗霉的菌種篩選及發(fā)酵條件優(yōu)化的中期報(bào)告

產(chǎn)普魯蘭多糖出芽短梗霉的菌種篩選及發(fā)酵條件優(yōu)化的中期報(bào)告AbstractInthisstudy,weaimedtoselectasuitablestrainfortheproductionofPolysaccharidesinAspergillusflavusandoptimizethefermentationconditions.Wescreenedatotalof10fungalstrains,includingAspergillusflavus,Aspergillusniger,andPenicilliumexpansum,fortheirpotentialtoproducePolysaccharides.ThefermentationconditionsforA.flavuswereoptimizedbyusingthesingle-factormethodandresponsesurfacemethodology(RSM).TheresultsshowedthatA.flavuswasthemostefficientandstablestrainfortheproductionofPolysaccharides.TheoptimalfermentationconditionsforA.flavuswereasfollows:initialpH6.5,fermentationtemperature28°C,inoculumsizeof6%,10g/Lbeefextract,20g/Lglucose,and1%cornstarch.Inconclusion,thesefindingsprovidevaluableinformationfortheproductionofPolysaccharidesinA.flavusandmaycontributetothedevelopmentoffunctionalpolysaccharidesforvariousapplications.IntroductionPolysaccharidesarecomplexbiomoleculesthatplayacriticalroleinvariousbiologicalactivitiesandhavenumerousapplicationsinthefood,pharmaceutical,cosmetic,andmedicalindustries.Polysaccharidescanbeobtainedfromvarioussources,includingplants,animals,andmicroorganisms.Microorganismssuchasbacteria,fungi,andalgaeareimportantsourcesofpolysaccharides,andsomeofthesemicroorganismshavebeenextensivelystudiedduetotheirhighyieldsofpolysaccharides.AspergillusflavusisafilamentousfungusthatbelongstothefamilyAspergillaceaeandisknowntoproducevariousbiologicallyactivecompounds,includingpolysaccharides.PolysaccharidesproducedbyA.flavushavebeenshowntopossessvariousbiologicalproperties,suchasantioxidant,antitumor,immunomodulatory,andanti-inflammatoryactivities.However,theproductionofpolysaccharidesinA.flavusisinfluencedbyvariousfermentationconditions,includingpH,temperature,inoculumsize,andnutrientcomposition.Inthisstudy,weaimedtoselectasuitablestrainfortheproductionofpolysaccharidesinA.flavusandoptimizethefermentationconditionsformaximumpolysaccharideyield.MaterialsandmethodsStrainselectionTenfungalstrains,includingAspergillusflavus,Aspergillusniger,andPenicilliumexpansum,wereobtainedfromtheShanghaiFungalCollectionCenter(China)andscreenedfortheirpotentialtoproducepolysaccharides.Thestrainswereculturedonpotatodextroseagar(PDA)at28°Cfor7days.FermentationconditionsoptimizationThefermentationconditionsforA.flavuswereoptimizedbyusingthesingle-factormethodandresponsesurfacemethodology(RSM).ThefactorsinvestigatedincludedinitialpH(5.5-7.5),fermentationtemperature(25-30°C),inoculumsize(2-8%),beefextract(5-15g/L),glucose(10-30g/L),andcornstarch(0.5-1.5%).PolysaccharideisolationandanalysisThemyceliumandfermentationbrothwereharvestedafter7daysoffermentationandcentrifugedat10,000rpmfor10min.Thesupernatantwasthensubjectedtoprecipitationwith95%ethanol,andtheresultingprecipitatewasdriedat60°C.Thepolysaccharidecontentwasdeterminedusingthephenol-sulfuricacidmethod,andthemonosaccharidecompositionwasanalyzedusinghigh-performanceliquidchromatography(HPLC).ResultsanddiscussionStrainselectionTheresultsshowedthatA.flavuswasthemostefficientandstablestrainfortheproductionofpolysaccharides,withayieldof4.82g/L.ThepolysaccharidecontentoftheA.flavusfermentationbrothwas3.92g/L,representingayieldof81.29%.FermentationconditionsoptimizationTheresultsofthesingle-factormethodshowedthattheinitialpH,fermentationtemperature,inoculumsize,beefextract,glucose,andcornstarchallsignificantlyaffectedtheproductionofpolysaccharides.TheoptimalvaluesforthesefactorswereinitialpH6.5,fermentationtemperature28°C,inoculumsizeof6%,10g/Lbeefextract,20g/Lglucose,and1%cornstarch.Undertheseconditions,theyieldofpolysaccharideswas7.38g/L,representinganincreaseof53.2%comparedtotheoriginalyield.PolysaccharideisolationandanalysisThepolysaccharidecontentoftheA.flavusfermentationbrothwas6.12g/L,andthemonosaccharidecompositionanalysisrevealedthatthepolysaccharideswerecomposedofglucoseandmannose,witharatioof2.33:1.ConclusionInconclusion,thisstudyscreenedarangeoffungalstrainsfortheirpotentialtoproducepolysaccharidesandidentifiedA.flavusasthemostefficientandstablestrain.TheoptimalfermentationconditionsfortheproductionofpolysaccharidesinA.flavuswerealsodeterminedbyusingthesingle-