Unicellular green algae, a promising source for renewable biofuels, produce lipid-rich biomass from light and CO₂. Productivity in photo-bioreactors is affected by inhomogeneous light distribution from high cell pigment causing heat dissipation of light energy absorbed in excess and shading of the deep layers. Contrasting reports have been published on the relation between photoprotective energy dissipation and productivity. Here, we have re-investigated the relation between energy quenching (qE) activity, photodamage and light use efficiency by comparing WT and two Chlamydomonas reinhardtii strains differing for their complement in LHCSR proteins, which catalyse dissipation of excitation energy in excess (qE). Strains were analysed for ROS production, protein composition, rate of photodamage and productivity assessed under wide light and CO₂ conditions.

The strain lacking LHCSR1 and knocked down in LHCSR3, thus depleted in qE, produced O₂ at significantly higher rate under high light, accompanied by enhanced singlet oxygen release and PSII photodamage. However, biomass productivity of WT was delayed in respect for mutant strains under intermittent light conditions only, implying that PSII activity was not the limiting factor under excess light. Contrary to previous proposals, domestication of Chlamydomonas for carbon assimilation rate in photo-bioreactors by down-regulation of photoprotective energy dissipation was ineffective in increasing algal biomass productivity.

单细胞绿藻是可再生生物燃料的一种有前途的来源，可利用光和 CO ₂生产富含脂质的生物质。光生物反应器的生产率受到高细胞色素的不均匀光分布的影响，导致过量吸收的光能的散热和深层阴影。已经发表了关于光保护能量耗散和生产力之间关系的对比报告。在这里，我们通过比较 WT 和两种莱茵衣藻重新研究了能量猝灭 (qE) 活性、光损伤和光利用效率之间的关系菌株在 LHCSR 蛋白中的补体不同，这些蛋白催化过量激发能量 (qE) 的耗散。分析菌株的 ROS 产生、蛋白质组成、光损伤率和在宽光和 CO ₂条件下评估的生产力。

缺乏LHCSR1并在LHCSR3中被击倒的菌株，因此在qE中耗尽，在高光下以显着更高的速率产生O ₂，伴随着增强的单线态氧释放和PSII光损伤。然而，仅在间歇光照条件下，突变株的 WT 生物量生产力延迟，这意味着 PSII 活性不是过量光照下的限制因素。与之前的提议相反，通过下调光保护能量耗散来驯化衣藻以提高光生物反应器中的碳同化率在提高藻类生物质生产力方面是无效的。