title: Influence of exogenous CO₂ on biomass and lipid accumulation of microalgae Auxenochlorella protothecoides cultivated in concentrated municipal wastewater.
abstract: The effects of exogenous CO₂ on the growth and lipid accumulation of a local screened facultative heterotrophic microalgae strain Auxenochlorella protothecoides (UMN280) as well as nutrient removal from concentrated municipal wastewater stream (centrate) were examined in this study. A 12-day batch experiment was conducted with CO₂ aeration at three levels, namely, 0%, 1%, and 5% (v/v) CO₂ mixed with air, under light intensity of 60 μmol/(m² @@s). A two-stage growth pattern was observed. The first stage (first-fifth day) was dominated by heterotrophic growth in which organic carbon was the main carbon source. The second stage (6th-12th day) was dominated by autotrophic growth in which exogenous CO₂ had a positive effect on algal biomass accumulation. The addition of 5% CO₂ was better than that of 1% CO₂ on the biomass and lipid production. The uptakes of nutrients were similar between injection and no injection of CO₂, except on phosphorus removal which was affected by the acidification of CO₂.
authors.affiliation: Center for Biorefining and Department of Bioproducts and Biosystems Engineering, University of Minnesota, 1390 Eckles Ave, St. Paul, MN 55108, USA.
authors.forename: Bing
authors.initials: B
authors.lastname: Hu
authors.forename: Min
authors.initials: M
authors.lastname: Min
authors.forename: Wenguang
authors.initials: W
authors.lastname: Zhou
authors.forename: Yecong
authors.initials: Y
authors.lastname: Li
authors.forename: Michael
authors.initials: M
authors.lastname: Mohr
authors.forename: Yanling
authors.initials: Y
authors.lastname: Cheng
authors.forename: Hanwu
authors.initials: H
authors.lastname: Lei
authors.forename: Yuhuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Lin
authors.forename: Paul
authors.initials: P
authors.lastname: Chen
authors.forename: Roger
authors.initials: R
authors.lastname: Ruan
mesh_terms: D056804:Biofuels; D018533:Biomass; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000494:pharmacology*; D002708:Chlorella / Q000187:drug effects* / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D008055:Lipids / Q000096:biosynthesis*; D058086:Microalgae / Q000187:drug effects* / Q000502:physiology; D010100:Oxygen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D014865:Waste Disposal, Fluid
chemical_list: D056804:Biofuels; D008055:Lipids; D002245:Carbon Dioxide; D010758:Phosphorus; D002244:Carbon; D010100:Oxygen