Bonnefond Hubert, Grimaud Ghjuvan, Rumin Judith, Bougaran Gaël, Talec Amélie, Gachelin Manon, Boutoute Marc, Pruvost Eric, Bernard Olivier, Sciandra Antoine
Sorbonne Universités, UPMC Univ Paris 06, CNRS-INSU, Laboratoire d'Océanographie de Villefranche-sur-mer (LOV), Villefranche-sur-mer, France.
INRIA BIOCORE, Sophia Antipolis Cedex, France.
PLoS One. 2017 Sep 13;12(9):e0183547. doi: 10.1371/journal.pone.0183547. eCollection 2017.
Temperature plays a key role in outdoor industrial cultivation of microalgae. Improving the thermal tolerance of microalgae to both daily and seasonal temperature fluctuations can thus contribute to increase their annual productivity. A long term selection experiment was carried out to increase the thermal niche (temperature range for which the growth is possible) of a neutral lipid overproducing strain of Tisochrysis lutea. The experimental protocol consisted to submit cells to daily variations of temperature for 7 months. The stress intensity, defined as the amplitude of daily temperature variations, was progressively increased along successive selection cycles. Only the amplitude of the temperature variations were increased, the daily average temperature was kept constant along the experiment. This protocol resulted in a thermal niche increase by 3°C (+16.5%), with an enhancement by 9% of the maximal growth rate. The selection process also affected T. lutea physiology, with a feature generally observed for 'cold-temperature' type of adaptation. The amount of total and neutral lipids was significantly increased, and eventually productivity was increased by 34%. This seven month selection experiment, carried out in a highly dynamic environment, challenges some of the hypotheses classically advanced to explain the temperature response of microalgae.
温度在微藻户外工业养殖中起着关键作用。因此，提高微藻对每日和季节性温度波动的耐热性有助于提高其年生产力。开展了一项长期选择实验，以扩大一株中性脂质高产的金藻（Tisochrysis lutea）的热生态位（能够生长的温度范围）。实验方案是让细胞在7个月的时间里经历每日温度变化。应激强度定义为每日温度变化的幅度，在连续的选择周期中逐渐增加。实验过程中仅提高了温度变化的幅度，每日平均温度保持恒定。该方案使热生态位增加了3°C（+16.5%），最大生长速率提高了9%。选择过程也影响了金藻的生理机能，这是“低温”型适应性普遍观察到的一个特征。总脂质和中性脂质的含量显著增加，最终生产力提高了34%。在高度动态的环境中进行的这项为期7个月的选择实验，对一些传统上用于解释微藻温度响应的假设提出了挑战。
