[P006] Poster

1:00 PM - 1:50 PM JST(4:00 AM - 4:50 AM UTC)

[P03-372] Analyses of growth and stress responses of microalgae under high-temperature and high-pH conditions

○Nagi Morita¹, Tsuyoshi Takeshita^1,2, Hayato Ozaki¹, Mone Ishida¹, Yoji Okabe¹, Tomoe Kodama¹, Yayoi Inui¹, Tomoko M Matsunaga¹, Kazuhide Tsuneizumi³, Yusuke Kazama³, Tomoko Abe³, Shinichiro Maruyama¹, Sachihiro Matsunaga¹ (1. Graduate School of Frontier Sciences, The University of Tokyo (Japan), 2. Graduate School of Human and Environmental Studies, Kyoto University (Japan), 3. RIKEN Nishina Center for Accelerator-Based Science (Japan))

Keywords:

Microalgae,Mutagenesis,Gene expression analysis,High-temperature stress,High-pH conditions

To realize a sustainable society, the development of production technologies utilizing microalgae for food, fuel, and high-value-added compounds is advancing. Microalgae have attracted attention as a highly resource-efficient production system, owing to their ability to be cultivated on idle land outside of agricultural areas and in coastal zones, as well as the fact that the majority of algal biomass can be utilized.However, the high production costs have hindered progress toward large-scale outdoor cultivation. One contributing factor to increased production costs is the operational costs. In outdoor cultivation, culture stability is prone to be compromised by fluctuations in temperature and pH, as well as the occurrence of contamination, which tends to drive up operational costs.As a countermeasure to this problem, cultivation utilizing high-pH industrial wastewater and similar sources has attracted attention. In this cultivation system, in addition to the suppression of contamination by the alkaline environment, cost reductions are expected through improved inorganic carbon retention in the medium and the utilization of nutrients contained in wastewater. However, the physiological responses of microalgae under such high-pH environments and high-temperature conditions are not yet sufficiently understood.In this study, we analyze the growth characteristics of green algae (e.g., species of the genus Chlorella) and cyanobacteria under high-temperature and high-pH conditions. We also conduct gene expression analyses to elucidate the underlying stress response mechanisms. Furthermore, we introduce mutations via heavy-ion beam irradiation, with the aim of obtaining strains that exhibit high growth capability even under high-temperature and high-pH conditions. Based on these findings, this study aims to contribute to the development of new microalgal strains suitable for efficient large-scale cultivation in alkaline environments.