The developmentofsustainable,bio-basedtechnologiestoconvertsolarenergyandcarbondioxideinto
fuels isagrandchallenge.Acorepartofthischallengeistoproduceafuelthatiscompatiblewiththe
existingtransportationinfrastructure.Thistaskisfurthercompoundedbythecommercialdesireto
separatethefuelfromthebiotechnologicalhost.Basedonitsfuelcharacteristics,1-octanolwas
identified asanattractivemetabolictargetwithdiesel-likeproperties.Wethereforeengineereda
synthetic pathwayspecifically forthebiosynthesisof1-octanolin Escherichiacoli BL21(DE3)byover-
expressionofthreeenzymes(thioesterase,carboxylicacidreductaseandaldehydereductase)andone
maturation factor(phosphopantetheinyltransferase).Inductionofthispathwayinashake flask resulted
in 4.4mg1-octanolL1 h1 which exceededtheproductivityofpreviouslyengineeredstrains.
Furthermore,themajority(73%)ofthefattyalcoholwaslocalisedwithinthemediawithoutthe
addition ofdetergentorsolventoverlay.Thedeletionof acrA reduced theproductionandexcretionof
1-octanol by3-foldrelativetothewild-type,suggestingthattheAcrAB–TolCcomplexmaybe
responsible forthemajorityofproductefflux. Thisstudypresents1-octanolasapotentialfueltarget
that canbesynthesisedandnaturallyaccumulatedwithinthemediausingengineeredmicrobes.
& 2014TheAuthors.PublishedbyElsevierB.V.InternationalMetabolicEngineeringSociety.Thisisan
open accessarticleundertheCCBYlicense