title: Effects of the operational conditions on the production of 1,3-propanediol derived from glycerol in anaerobic granular sludge reactors.
abstract: The aim of this study has been to produce 1,3-propanediol (1,3-PDO) from glycerol (gly) fermentation by means of a microbial mixed culture (granular sludge), as well as to establish the operational conditions of two up-flow anaerobic sludge blanket (UASB) reactors in order to achieve a maximum 1,3-PDO yield. The UASB reactors with initial pH values set at 6.8 and 5.5 were operated at 30 °C during 165 days. Thirteen variables were previously screened by a Plackett-Burman (PB) design; results showed that yeast extract, MgSO4and methanogenesis inhibition (by heat shock) showed a positive effect, whereas high glycerol concentration, tryptone and CaCl2showed a negative impact on the 1,3-PDO produced by glycerol degradation. Following four experimental periods, the highest average yield of 0.43 mol 1,3-PDO mol-1gly was achieved when sodium bicarbonate was added to the reactors. Propionate and acetate were also produced and a high microorganism diversity was detected; however, the restrictive operational conditions of the reactors led to the death of the methanogenic archaea. Nevertheless, the continuous production of 1,3-PDO from glycerol within UASB reactors inoculated with granular sludge can be considered highly feasible.
authors.affiliation: Department of Civil Engineering, Federal University of Pernambuco, Laboratory of Environmental Sanitation, Av. Acadêmico Hélio Ramos s/n, Cidade Universitária, CEP: 50740-530, Recife, PE, Brazil.
authors.forename: Mitsue M
authors.initials: MM
authors.lastname: Nakazawa
authors.affiliation: Department of Civil Engineering, Federal University of Pernambuco, Laboratory of Environmental Sanitation, Av. Acadêmico Hélio Ramos s/n, Cidade Universitária, CEP: 50740-530, Recife, PE, Brazil.
authors.forename: Lourdinha
authors.initials: L
authors.lastname: Florencio
authors.affiliation: Department of Civil Engineering, Federal University of Pernambuco, Laboratory of Environmental Sanitation, Av. Acadêmico Hélio Ramos s/n, Cidade Universitária, CEP: 50740-530, Recife, PE, Brazil.
authors.forename: Mario T
authors.initials: MT
authors.lastname: Kato
authors.affiliation: Department of Civil Engineering, Federal University of Pernambuco, Laboratory of Environmental Sanitation, Av. Acadêmico Hélio Ramos s/n, Cidade Universitária, CEP: 50740-530, Recife, PE, Brazil.
authors.forename: Savia
authors.initials: S
authors.lastname: Gavazza
authors.affiliation: Department of Molecular Biology, Autonomous University of Madrid, C/ Darwin 2, Madrid 28049, Spain E-mail: joseluis.sanz@uam.es.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Sanz
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors / Q000382:microbiology*; D019605:Euryarchaeota / Q000378:metabolism; D005285:Fermentation; D005990:Glycerol / Q000378:metabolism*; D011409:Propylene Glycols / Q000032:analysis*; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D013499:Surface Properties
chemical_list: D011409:Propylene Glycols; D012722:Sewage; C041787:1,3-propanediol; D005990:Glycerol