Regions that offer high levels of sunlight are ideal to produce microalgae. However, as a result of high light intensities, the temperature in photobioreactors can reach temperatures up to 50 °C. Control of temperature is essential to avoid losses on biomass productivity but should be limited to a minimum to avoid high energy requirements for cooling. Our objective is to develop a production process in which cooling is not required. We studied the behaviour of thermotolerant microalgae Picochlorum sp. (BPE23) under four diel temperature regimes, with peak temperatures from 30 °C up to a maximum of 47.5 °C. The highest growth rate of 0.17 h⁻¹ was obtained when applying a daytime peak temperature of 40 °C. Operating photobioreactors in tropical regions, with a maximal peak temperature of 40 °C, up from 30 °C, reduces microalgae production costs by 26.2 %, based on simulations with a pre-existing techno-economic model. Cell pigmentation was downregulated under increasingly stressful temperatures. The fatty acid composition of cell membranes was altered under increasing temperatures to contain shorter fatty acids with a higher level of saturation. Our findings show that the level of temperature control impacts the biomass yield and composition of the microalgae.

提供高水平阳光的地区是生产微藻的理想场所。然而，由于高光强度，光生物反应器中的温度最高可达 50 °C。温度控制对于避免生物质生产力损失至关重要，但应限制在最低限度以避免冷却所需的高能量。我们的目标是开发一种不需要冷却的生产工艺。我们研究了耐热微藻Picochlorum sp.的行为。(BPE23)在四种柴油温度范围内，峰值温度从 30 °C 到最高 47.5 °C。0.17 h ^-1的最高增长率当应用 40 °C 的白天峰值温度时获得。基于现有技术经济模型的模拟，在热带地区运行光生物反应器，最高峰值温度从 30°C 上升到 40°C，可将微藻生产成本降低 26.2%。在压力越来越大的温度下，细胞色素沉着被下调。细胞膜的脂肪酸组成在升高的温度下发生变化，以包含具有更高饱和度的较短脂肪酸。我们的研究结果表明，温度控制水平会影响微藻的生物质产量和组成。