Improvement of microalgae biomass productivity and subsequent biogas yield of hydrothermal gasification via optimization of illumination

Daniel Fozer, Bernadett Kiss, Laszlo Lorincz, Edit Szekely, P. Mizsey, Aron Nemeth

Research output: Contribution to journalArticle

6 Citations (Scopus)


This study examines the light factorial optimization of Chlorella vulgaris microalgae cultivation under different wavelengths and light intensities. RGB light-emitting diodes were applied on microtiter plate and lab scale stirred tank photobioreactors. One-way ANOVA and response surface methodology were adopted to investigate the effects on biomass productivity. The highest biomass productivity is found at 243.5 and 96.8 μmol photon m −2 s −1 in case of red and blue color intensities, respectively. Scaled-up fermentation in stirred tank photobioreactors shows that changing light intensity and aeration settings result in differing biomass productivity and composition. The effects of targeted cultivation are investigated on hydrothermal gasification (HTG) which is carried out in tubular reactor system at 550 °C, 30.0 MPa and average 120 s residence time. It is found that the fermentation of microalgae under optimized light factor levels results in higher H 2 yield compared to unoptimized light intensity levels. Throughout the HTG process high H 2 yield is achieved (4.38–9.34 mol kg −1 ) without using any catalyst, which indicates that the efficiency of downstream processing can be increased already at the cultivation stage.

Original languageEnglish
Pages (from-to)1262-1272
Number of pages11
JournalRenewable Energy
Publication statusPublished - Aug 1 2019



  • Biogas production
  • Chlorella vulgaris
  • Cultivation
  • Hydrothermal gasification
  • Light optimization

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment

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