title: Microbial bio-based plastics from olive-mill wastewater: Generation and properties of polyhydroxyalkanoates from mixed cultures in a two-stage pilot scale system.
abstract: The operational efficiency of a two stage pilot scale system for polyhydroxyalkanoates (PHAs) production from three phase olive oil mill wastewater (OMW) was investigated in this study. A mixed anaerobic, acidogenic culture derived from a municipal wastewater treatment plant, was used in the first stage, aiming to the acidification of OMW. The effluent of the first bioreactor that was operated in continuous mode, was collected in a sedimentation tank in which partial removal of the suspended solids was taking place, and was then forwarded to an aerobic reactor, operated in sequential batch mode under nutrient limitation. In the second stage an enriched culture of Pseudomonas sp. was used as initial inoculum for the production of PHAs from the acidified waste. Clarification of the acidified waste, using aluminium sulphate which causes flocculation and precipitation of solids, was also performed, and its effect on the composition of the acidified waste as well as on the yields and properties of PHAs was investigated. It was shown that clarification had no significant qualitative or quantitative effect on the primary carbon sources, i.e. short chain fatty acids and residual sugars, but only on the values of total suspended solids and total chemical oxygen demand of the acidified waste. The type and thermal characteristics of the produced PHAs were also similar for both types of feed. However the clarification of the waste seemed to have a positive impact on final PHAs yield, measured as gPHAs/100g of VSS, which reached up to 25%. Analysis of the final products via nuclear magnetic resonance spectroscopy revealed the existence of 3-hydroxybutyrate (3HB) and 3-hydroxyoctanoate (HO) units, leading to the conclusion that the polymer could be either a blend of P3HB and P3HO homopolymers or/and the 3HB-co-3HO co-polymer, an unusual polymer occurring in nature with advanced properties.
authors.affiliation: Institute of Chemical Engineering Sciences, Foundation for Research and Technology (ICEHT/FORTH), 26504 Patras, Greece. Electronic address: ntaikou@iceht.forth.gr.
authors.forename: I
authors.initials: I
authors.lastname: Ntaikou
authors.affiliation: Labor Srl, Tecnopolo Tiburtino, Via Giacomo Peroni 386, 00131 Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Valencia Peroni
authors.affiliation: Institute of Chemical Engineering Sciences, Foundation for Research and Technology (ICEHT/FORTH), 26504 Patras, Greece.
authors.forename: C
authors.initials: C
authors.lastname: Kourmentza
authors.affiliation: Department of Chemistry and Industrial Chemistry, University of Pisa, 56126 Pisa, Italy.
authors.forename: V I
authors.initials: VI
authors.lastname: Ilieva
authors.affiliation: Department of Chemistry and Industrial Chemistry, University of Pisa, 56126 Pisa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Morelli
authors.affiliation: Department of Chemistry and Industrial Chemistry, University of Pisa, 56126 Pisa, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Chiellini
authors.affiliation: Institute of Chemical Engineering Sciences, Foundation for Research and Technology (ICEHT/FORTH), 26504 Patras, Greece; School of Chemical Engineering, National Technical University of Athens, 15780 Athens, Greece.
authors.forename: G
authors.initials: G
authors.lastname: Lyberatos
mesh_terms: D019649:Food Industry; D008970:Molecular Weight; D031658:Olea; D010865:Pilot Projects; D010969:Plastics; D054813:Polyhydroxyalkanoates / Q000378:metabolism*; D066244:Proton Magnetic Resonance Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared; D062065:Wastewater
chemical_list: D010969:Plastics; D054813:Polyhydroxyalkanoates; D062065:Wastewater
keywords: Acidification; DSC; Hydroxyoctanoate; OMW; Poly(hydroxyalkanoates)