title: End-product inhibition and acidification limit biowaste fermentation efficiency.
abstract: Converting waste to resource may mitigate environmental pollution and global resource limitation. The platform chemical lactic acid can be produced from biowaste and its liquid fraction after solid-liquid separation. A fermentation step for lactic acid production prior to the conversion of biowaste to methane and organic fertilizer would increase the biowaste's value. Despite the huge potential and promising results of the treatment procedure, the reasons for efficiency loss observed previously need to be addressed in order to pave the way for an up-scaling of the fermentation process. Therefore, biowaste was fermented applying pH control, acid extraction and glucose addition in order to counteract reasons such as acidification, end-product inhibition and carbon limitation, respectively. The fermentation was competitive compared to other renewable lactic acid production substrates and reached a maximum productivity of >5 g Clactic acidg(-1)Ch(-1) and a concentration exceeding 30 g L(-1). A combination of acidification and end-product inhibition was identified as major obstacle. Lactobacillus crispatus and its closest relatives were identified as key lactic acid producers within the process using Miseq Illumina sequencing.
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria. Electronic address: Maraike.Probst@uibk.ac.at.
authors.forename: Maraike
authors.initials: M
authors.lastname: Probst
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Walter
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Dreschke
authors.affiliation: Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Centro di Ricerca per lo Studio delle Relazioni tra Pianta e Suolo, Via Trieste 23, 34170 Gorizia, Italy.
authors.forename: Flavio
authors.initials: F
authors.lastname: Fornasier
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pümpel
authors.affiliation: Department of Statistics, University of Innsbruck, Universitätsstraße 15, 6020 Innsbruck, Austria.
authors.forename: Janette
authors.initials: J
authors.lastname: Walde
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria.
authors.forename: Heribert
authors.initials: H
authors.lastname: Insam
mesh_terms: D001709:Biotechnology / Q000379:methods*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000096:biosynthesis*; D007778:Lactobacillus / Q000378:metabolism; D008697:Methane / Q000096:biosynthesis*; D018505:Waste Management / Q000379:methods*
chemical_list: D019344:Lactic Acid; D008697:Methane
keywords: Fermentation; Lactate dehydrogenase; Lactobacillus; Microbiome; Waste treatment