title: Effects of CO2 and O2 concentrations and light intensity on growth of microalgae (Euglena gracilis) in CELSS.
abstract: Green microalgae are likely to play an important role in bioregenerative systems for producing food and converting CO2 to O2 in a controlled ecological life support system (CELSS). In the present study, a method for evaluating the effects of environmental variables on the multiplication rate of microalgal cells was developed to determine the optimum culture condition for a microalgal culture system that can function effectively in the CELSS. The microalga, Euglena gracilis, was cultured in water droplets (3 microliters in liquid volume each) in a vessel (25 ml in air volume) in which the CO2 and O2 concentrations were controlled. The number of Euglena cells cultured at CO2 concentrations ranging from 2% to 6%, O2 concentrations ranging from 5% to 20%, and PPF levels ranging from 50 to 100 micromoles m-2 s-1 was monitored by using a video camera and a microscope. The multiplication rate of cells was highest and the cell number increased by 8.3 times during 48 h under a condition of 4% CO2, 21% O2 and 100 micromoles m-2 s-1 PPF. The multiplication rate of the cells was highest at 4% CO2, followed by 6% and 2% CO2, and it decreased with decreasing O2 concentration and decreasing PPF.
authors.affiliation: College of Agriculture, Osaka Prefecture University, Sakai, Japan. kitaya@envi.osakafu-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Kitaya
authors.forename: S
authors.initials: S
authors.lastname: Kibe
authors.forename: M
authors.initials: M
authors.lastname: Oguchi
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: K
authors.initials: K
authors.lastname: Miyatake
authors.forename: Y
authors.initials: Y
authors.lastname: Nakano
mesh_terms: D000818:Animals; D019149:Bioreactors; D002245:Carbon Dioxide / Q000494:pharmacology*; D018929:Cell Culture Techniques / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D018504:Ecological Systems, Closed; D005056:Euglena gracilis / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects; D008027:Light; D010100:Oxygen / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen