Optimization of photosynthetic light energy utilization by microalgae

► A direct correlation exists between Chl a/b ratios and Photosystem II closure rate. ► Algae with intermediate antennae carry out state transitions and xanthophyll cycle. ► Algae with intermediate antennae have higher photosynthesis rates than wild-type. ► Antenna size of wild-type algae is optimal for light competition in mixed cultures.