Tuna, StepanIzaguirre, JonBondar, MarinaMarques, MafaldaFernandes, Pedro Carlos de BarrosFonseca, Maria Manuela Regalo daCesário, Maria2020-09Tuna , S , Izaguirre , J , Bondar , M , Marques , M , Fernandes , P C D B , Fonseca , M M R D & Cesário , M 2020 , ' Upgrading end-of-line residues of the red seaweed Gelidium sesquipedale to polyhydroxyalkanoates using Halomonas boliviensis ' , Default journal .1646-3730Biotechnology ReportsAgar extraction from Gelidium and Gracilaria red seaweed species produces hundred thousand ton of carbohydrate-rich residues annually. Gelidium sesquipedale waste biomass obtained after agar extraction, still contained 44.2 % w/w total carbohydrates (dry-weight basis). These residues were biologically up-graded to poly-3-hydroxybutyrate (P3HB) after saccharification of their carbohydrate fraction to simple sugars. A combined hydrolysis treatment using sulfamic acid followed by enzymatic hydrolysis with cellulases produced a glucose-rich hydrolysate with a negligible content of inhibitors. With this treatment a sugar yield of circa 30 % (g glucose/g biomass) was attained. The algal hydrolysates were assessed as carbon source for the production of P3HB by the halotolerant bacteria Halomonas boliviensis. A cell concentration of 8.3 g L−1 containing 41 % (w/w) of polymer and a yield (YP/S) of 0.16 gpolymer/gglucose were attained in shake flask assays. In this work, cellulose-rich seaweed waste was shown to be an upgradable, sustainable source of carbohydrates.application/pdfengopenAccessBIOTECNOLOGIAGELIDIUM SESQUIPEDALEHALOMONAS BOLIVIENSISRESÍDUOS DE ALGAS MARINHASPOLI-3-HIDROXIBUTIRATORESÍDUOS DE MACROALGASENGENHARIA BIOTECNOLÓGICAALGASBIOTECHNOLOGYGELIDIUM SESQUIPEDALEHALOMONAS BOLIVIENSISSEAWEED RESIDUESPOLY-3-HYDROXYBUTYRATEMACROALGAE RESIDUESBIOTECHNOLOGY ENGINEERINGALGAEarticle