title: Increase in biodegradation of dimethyl phthalate by Closterium lunula using inorganic carbon.
abstract: The effect and mechanism of inorganic carbon (IC) on the biodegradation of dimethyl phthalate (DMP) by a green microalga Closterium lunula was investigated. The growth of this microalga and the biodegradation of DMP were significantly enhanced when the initial IC was increased. An intermediate product of DMP biodegradation was identified as phthalic acid (PA) that was accumulated and caused a sharp decrease in pH of microalgal culture medium, which inhibited both the growth of microalga and the biodegradation of DMP. A suggested second-order kinetic equation of organic pollutant biodegradation by microalgae (-dC/dt = kNr) fitted well with the experimental data. The increase of IC caused a decline in biodegradation rate constant for organic carbon (k) and an increase in growth (N) by supplying a favorite carbon source and mitigating the decrease of pH. As the net effect, the overall biodegradation rate of DMP was promoted as IC increased, which was dominated by the increase of microalgal growth.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, P.O. Box 18, Beijing 100085, China. haiyan@mail.rcees.ac.cn
authors.forename: Hai
authors.initials: H
authors.lastname: Yan
authors.forename: Gang
authors.initials: G
authors.lastname: Pan
mesh_terms: D001673:Biodegradation, Environmental; D017554:Carbon Compounds, Inorganic / Q000378:metabolism*; D000460:Chlorophyta / Q000254:growth & development / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010795:Phthalic Acids / Q000378:metabolism*
chemical_list: D017554:Carbon Compounds, Inorganic; D010795:Phthalic Acids; C024629:dimethyl phthalate; C032279:phthalic acid