Influence of exogenous CO _2 on biomass and lipid accumulation of microalgae Auxenochlorella protothecoides cultivated in concentrated municipal wastewater

摘要

The effects of exogenous CO _2 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 CO _2 aeration at three levels, namely, 0%, 1%, and 5% (v/v) CO _2 mixed with air, under light intensity of 60 μmol/(m ~2 @@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 CO _2 had a positive effect on algal biomass accumulation. The addition of 5% CO _2 was better than that of 1% CO _2 on the biomass and lipid production. The uptakes of nutrients were similar between injection and no injection of CO _2, except on phosphorus removal which was affected by the acidification of CO _2.