Chemo-enzymatic pathway design mergescomplimentaryenzymatic and chemicalreactions strengthstoexpand the biomolecular design space.While chemical reactions struggle with regioselectivity and stereoselectivity, biological processes encounter limitations such as product toxicity and enzyme scarcity.Optimallyintegratingboth approaches provides an opportunity toidentify efficient pathways beyond the capabilities of eitherapproach.Recently, numerous studies have shown the advantages of leveraging enzymatic steps into industrial-scale chemical processes such as for the blood sugar regulator Sitagliptin (Merck) andfor the treatment of AIDS,a protease inhibitorDarunavir(Prozomix).Designing optimal chemo-enzymatic pathways is a complex task and requires navigating a high-dimensional search space of potential reactions that combines individual chemical and biochemical steps.Unlike retrosynthesis which recursively traces back froma giventarget molecule to the starting precursorone step at a time,wesolvea mixed-integer linear programming algorithm(MILP)todiscoverentire pathwaysby traversing reaction rules ofknown chemical and enzymaticconnectionsextracted from USPTOandMetaNetXdatabasesrespectively.The algorithmminimizesthe number oftransitions between chemical and biological reactions,hencecutting down on multiple stages ofseparation and purificationrequired foreachswitch between enzymatic and chemical reaction environments.Our approach has been validated through case studiesonfour molecules:2-5-Furandicarboxylic acid, Terephthalate, 3-Hydroxybutyrate, and α-Pinene,whichdemonstrates our capability to identify previously reportedtotal synthesis pathwayswhile also exploring alternative routeswithdifferentchemicalreactionconditionsandoutcomessuch astemperature and yieldrespectively.Thiseffortcontributestosearch fortotalsynthesis pathwaysleveraging knownreactionsandstreamlinesthe planning ofchemical synthesis potentially leading to the development of more effective synthesis strategies, accessiblethroughopen-sourcecodefor users. (https://github.com/maranasgroup/chemo-enz).