title: Lactic acid and methane: improved exploitation of biowaste potential.
abstract: This feasibility study investigated a two-step biorefining approach to increase the value gained by recycling of organic municipal solid waste. Firstly, lactic acid was produced via batch fermentation at 37°C using the indigenous microbiome. Experiments revealed an optimal fermentation period of 24h resulting in high yields of lactic acid (up to 37gkg(-1)). The lactic acid proportion of total volatile fatty acid content reached up to 83%. Lactobacilli were selectively enriched to up to 75% of the bacterial community. Additionally conversion of organic matter to lactic acid was increased from 22% to 30% through counteracting end product inhibition by continuous lactic acid extraction. Secondly, fermentation residues were used as co-substrate in biomethane production yielding up to 618±41Nmlbiomethaneg(-1) volatile solids. Digestate, the only end product of this process can be used as organic fertilizer.
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria. Electronic address: gillidreschke@gmx.at.
authors.forename: G
authors.initials: G
authors.lastname: Dreschke
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria. Electronic address: Maraike.Probst@uibk.ac.at.
authors.forename: M
authors.initials: M
authors.lastname: Probst
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria. Electronic address: a.walter@uibk.ac.at.
authors.forename: A
authors.initials: A
authors.lastname: Walter
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria. Electronic address: Thomas.Puempel@uibk.ac.at.
authors.forename: T
authors.initials: T
authors.lastname: Pümpel
authors.affiliation: Department of Statistics, University of Innsbruck, Universitätsstraße 15, 6020 Innsbruck, Austria. Electronic address: Janette.Walde@uibk.ac.at.
authors.forename: J
authors.initials: J
authors.lastname: Walde
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria. Electronic address: Heribert.Insam@uibk.ac.at.
authors.forename: H
authors.initials: H
authors.lastname: Insam
mesh_terms: D001483:Base Sequence; D056804:Biofuels; D001709:Biotechnology / Q000379:methods*; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis; D005285:Fermentation; D059014:High-Throughput Nucleotide Sequencing; D019344:Lactic Acid / Q000096:biosynthesis* / Q000302:isolation & purification; D007778:Lactobacillus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D008697:Methane / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012037:Refuse Disposal / Q000379:methods*; D013997:Time Factors
chemical_list: D056804:Biofuels; D017931:DNA Primers; D019344:Lactic Acid; D008697:Methane
keywords: Biogas potential; Fermentation; Lactobacillus; Municipal organic solid waste; Waste treatment