Abstract

In photobioreactors and natural systems, microalgae are subjected to rapidly changing light intensities (LI) due to light attenuation and mixing. A controlled way to study the effect of rapidly changing LI is to subject cultures to flashing light. In this study, series of flashing-light experiments were conducted using Synechocystis sp. PCC6803 with constant overall average LI of approximately 84 μmol·m−2·s−1 and relative times in the light and dark varied. The results were also compared with simulated results using a mathematical model including an absorbed pool of light energy, photoacclimation, and photoinhibition. With equal time in light and dark, the specific growth rate (μ) systematically decreased with increasing light duration, and µ decreased further when the ratio of light to dark was decreased. The model captured both trends with the mechanistic explanation that when the light duration was very short the changes in the pool of absorbed LI were smoothed out across the light and dark periods, whereas longer durations caused the biomass to experience discrete light and dark conditions that lead to reduced light absorption, more energy loss to nonphotochemical quenching, and more photodamage. These growth effects were accentuated as the ratio of light to dark decreased.

Original languageEnglish (US)
Pages (from-to)469-474
Number of pages6
JournalBiotechnology and bioengineering
Volume116
Issue number2
DOIs
StatePublished - Feb 2019

Keywords

  • Synechocystis sp. PCC6803
  • flashing light
  • light-dependent kinetics
  • mathematical modeling
  • microalgae

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology

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