Results in Engineering (Mar 2023)

CO2 favors the lipid and biodiesel production of microalgal-bacterial granular sludge

  • Baihui Cui,
  • Cheng Liu,
  • Hongwei Rong,
  • Shiyi Luo,
  • Dabin Guo,
  • Bin Ji

Journal volume & issue
Vol. 17
p. 100980

Abstract

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Microalgal-bacterial granular sludge (MBGS) serves as an environmentally friendly wastewater treatment technology with CO2 capture potential. Accordingly, this study intended to investigate the lipid and biodiesel production of MBGS with CO2 addition. The results showed that CO2 addition could increase not only the total lipid content in MBGS but also the biodiesel quality. The total lipid content in MBGS typically increased from 725.92 mg/L to 1056.55 mg/L with CO2 addition during the 30 days experiment. Furthermore, when CO2 was added, the C18:1 content of MBGS increased significantly from 0.17 (μg/mg)·FW to 0.22 (μg/mg)·FW, indicating that higher quality of biodiesel might be produced. Saturated fatty acid and polyunsaturated fatty acids contents of MBGS with CO2 addition were respectively 1.30 (μg/mg)·FW and 0.13 (μg/mg)·FW, while the monounsaturated fatty acids content of MBGS with CO2 addition was higher than without CO2 addition. This indicated that the MBGS system with CO2 addition appeared to be better suited for producing biodiesel. Microbial community further analysis revealed that CO2 addition might promote the growth of Chlorophyta, Cyanobacteria and Chloroflexi. This background information would aid in promoting the further application of MBGS for carbon capture and resource recovery towards carbon neutral or negative wastewater treatment.

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