title: Applicability of Euglena gracilis for biorefineries demonstrated by the production of α-tocopherol and paramylon followed by anaerobic digestion.
abstract: In this study the use of Euglena gracilis biomass for α-tocopherol, paramylon and biogas production in a value-added chain was investigated. Therefore, we analyzed the dry cell weight and product concentrations at different growth phases during heterotrophic, photoheterotrophic and photoautotrophic cultivation in a low-cost minimal medium. Furthermore, the specific biogas yields for differently derived biomass with and without product recovery were investigated. We demonstrate that growth phase and cultivation mode not only have a significant impact on product formation, but also influence the yield of biogas obtained from anaerobic digestion of Euglena gracilis biomass. The maximum dry cell weight concentration ranged from 12.3±0.14gL(-1) for heterotrophically to 3.4±0.02gL(-1) for photoautotrophically grown Euglena gracilis cells. The heterotrophically grown biomass accumulated product concentrations of 5.3±0.12mgL(-1) of α-tocopherol and 9.3±0.1gL(-1) of paramylon or 805±10.9mL of biogasgvs(-1) (per gram volatile solids). The results for photoautotrophically grown cells were 8.6±0.22mgL(-1) of α-tocopherol and 0.78±0.01gL(-1) of paramylon or 648±7.2mL of biogasgvs(-1). For an energy-saving downstream procedure the extracting agent methanol does not have to be removed strictly. Samples with residual methanol showed a significantly increased biogas yield, because the solvent can be used as an additional substrate for methane production by archaebacteria.
authors.affiliation: Chair of Fermentation Engineering, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany. Electronic address: pgr@fermtech.techfak.uni-bielefeld.de.
authors.forename: Philipp
authors.initials: P
authors.lastname: Grimm
authors.affiliation: Chair of Fermentation Engineering, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany.
authors.forename: Joe M
authors.initials: JM
authors.lastname: Risse
authors.affiliation: Chair of Fermentation Engineering, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Cholewa
authors.affiliation: Chair of Fermentation Engineering, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany.
authors.forename: Jakob M
authors.initials: JM
authors.lastname: Müller
authors.affiliation: City for Scientific Research & Technology Applications, Genetic Engineering and Biotechnology Research Institute (GEBRI), Bioprocess Development Department, New Bourg, El-Arab City, 21934 Alexandria, Egypt.
authors.forename: Usama
authors.initials: U
authors.lastname: Beshay
authors.affiliation: Chair of Fermentation Engineering, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Friehs
authors.affiliation: Chair of Fermentation Engineering, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany.
authors.forename: Erwin
authors.initials: E
authors.lastname: Flaschel
mesh_terms: D056804:Biofuels; D018533:Biomass; D005056:Euglena gracilis / Q000254:growth & development / Q000378:metabolism*; D005285:Fermentation; D005936:Glucans / Q000378:metabolism*; D052836:Heterotrophic Processes; D008697:Methane / Q000096:biosynthesis; D052817:Phototrophic Processes; D024502:alpha-Tocopherol / Q000378:metabolism*
chemical_list: D056804:Biofuels; D005936:Glucans; C003045:paramylon; D024502:alpha-Tocopherol; D008697:Methane
keywords: Biogas; Biorefinery concept; Euglena gracilis; High-value products; Paramylon; α-Tocopherol