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Y.Chenetal./ProcessBiochemistry40(2005)723–732729ratioswerereportedbetween1.33and1.80mol-C/mol-C(Table4).VeryfewresearchersinvestigatedpropionicacidoritsmixturewithaceticacidaffectingPHA/SCFAratio[14,33].Lemosetal.[33]studiedtheinfluenceofdifferentSCFAonPHAaccumulationinbatchexperimentsandfoundthatthePHAproductionwithpropionicandaceticacidwere,respectively,1.12and1.47mol-C/mol-C-SCFA.Satohetal.[14]observedthatpropionicandaceticacidhadthesamemolarratioofPHAtoSCFA(0.67mol-PHA/mol-SCFA).InthisstudythePHA/SCFAratioinexperimentAwas1.71mol-C/mol-C,whichwasinthereportedrangeof1.33–1.80mol-C/mol-C.Nevertheless,inexperimentsAPandP,thePHA/SCFAratiosbecame1.19mol-C/mol-C(unacclimatedbiomass)and0.98mol-C/mol-C(acclimatedbiomass).PHAaccumulationinbothexperimentsAPandP(i.e.propionicacidenrichedwastewater)wasmuchlowerthaninexperimentA(aceticacidenrichedwastewater).Inaddition,asshowninTable3,thePHA/SCFAratiodecreasedby18.65%afterthebiomasswasacclimated(from1.19inexperimentAPto0.98inexperimentP).Oneexplanationforthisphenomenonwasduetoalessglycogendegradationwiththeacclimatedbiomassforpro-vidingNADH2requiredforPHAsynthesis,lessPHAwere,therefore,produced.3.3.ComparisonofaerobictransformationinbatchexperimentsIntheaerobicstage,PHAdegradationisthesourceofphosphorusuptake,glycogenformationandcellgrowth[34].TheSOP,PHAandglycogentransformationsduringaer-obicphaseareillustratedinTable5.ThePHAdegrada-tioninexperimentAPwas2.55mmol-C/g-MLVSS,whichwasslightlyhigherthaninexperimentP(2.33mmol-C/g-MLVSS).ThisdifferenceofPHAaerobicdegradationbe-tweenexperimentsAPandPwascausedbytheiranaerobicPHAsynthesis.TheanaerobicPHAaccumulationinexper-imentsAPandPwere2.42and2.17mmol-C/g-MLVSS,Table5Averageaerobictransformationinbatchexperiments(n=6)aExperimentno.AAPPP/APPHAdegradation(mmol-C/g-MLVSS)Average3.732.552.330.91Standarddeviation0.090.010.060.02PHB-degradation/PHV-degradation(mol-C/mol-C)Average2.270.230.351.52Standarddeviation0.070.010.020.04Glycogen-synthesis(mmol-C/g-MLVSS)Average1.741.391.300.94Sta