Cell membrane fatty acid changes and desaturase expression of Saccharomyces bayanus exposed to high pressure homogenization in relation to the supplementation of exogenous unsaturated fatty acids

Aims:TheaimofthisworkwastostudytheresponsesofSaccharomycesbayanuscellsexposedtosub-lethalhigh-pressurehomogenization(HPH)anddeterminewhethertheplasmaticmembranecansenseHPHinthepresence,orabsence,ofexogenousunsaturatedfattyacids(UFAs)inthegrowthmedium.MethodsandResults:High-pressurehomogenizationdamagedandcausedthecollapseofcellwallsandmembranesofaportionofcells;however,HPHdidnotsignificantlyaffectS.bayanuscellviability(lessthan0.3LogCFUml−1).HPHstronglyaffectedthemembranefattyacid(FA)compositionbyincreasingthepercentageoftotalUFAwhencomparedwithsaturatedfattyacids.ThegeneexpressionshowedthatthetranscriptionofOLE1,ERG3,andERG11increasedafterHPH.ThepresenceofexogenousUFAabolishedHPH- inducedeffectsontheOLE1andERG3genes,increasedthepercentageofmembranelipidsanddecreasedtheexpressionofOLE1andERG3within30minoftreatment.Conclusion:TheresultssuggestakeyroleforUFAinthemicrobialcellresponsetosub-lethalstress.Inaddition,thesedataprovideinsightintothemolecularbasisoftheresponseofS.bayanustothisinnovativetechnology.SignificanceandImpactoftheStudy:Elucidationofthemechanismofactionforsub-ethalHPHwillenabletheutilizationofthistechnologytomodulatethestarterperformanceattheindustrialscale.