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Growth kinetics and mathematical modeling of Synechocystis sp. PCC 6803 under flashing light
Author(s) -
Straka Levi,
Rittmann Bruce E.
Publication year - 2019
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.26862
Subject(s) - photobioreactor , flashing , photoinhibition , light intensity , absorption (acoustics) , luminous intensity , chemistry , photosynthesis , optics , biomass (ecology) , physics , biology , ecology , photosystem ii , biochemistry
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.