Generation of non-motile Euglena gracilis by genome editing

September 9, 2022

To improve the harvesting efficiency in industrial applications

A Research group of the RIKEN Baton Zone Program in the RIKEN Cluster for Science, Technology and Innovation Hub, the RIKEN CSRS, Euglena Co., Ltd., and the RIKEN Center for Advanced Photonics successfully generated non-motile mutants of Euglena gracilis (E. gracilis), an industrially exploited species Euglena algae, by genome editing for the first time.

The cost of harvesting mass-cultivated algal cells by means such as centrifugation is said to account for up to 20-30% of the total production cost for industrial use. Improving the harvesting efficiency, therefore, is the key to reducing the production cost.

In this study, the researchers successfully generated non-motile strains of E. gracilis that lack genes involved in flagella formation necessary for swimming using the previously established highly efficient genome-editing technology for E. gracilis. Since the non-flagella and non-motile strains of E. gracilis cannot swim, almost all of them precipitate by allowing the culture medium to stand still, making it easy to collect the E. gracilis. The non-motile mutants show equal abilities compared to the wild type (normal) in terms of growth, paramylon accumulation, and lipids production for biofuel. The mutants thus have less motility while maintaining their industrial usefulness.

The results of this study would improve the production efficiency of E. gracilis, which has been industrially used as a material for food and biofuel.

Original article
Plant Biotechnology Journal doi:10.1111/pbi.13904
M. Ishikawa, T. Nomura, S. Tamaki, K. Ozasa, T. Suzuki, K. Toyooka, K. Hirota, K. Yamada, K. Suzuki, K. Mochida,
"CRISPR/Cas9-mediated generation of non-motile mutants to improve the harvesting efficiency of mass-cultivated Euglena gracilis".
Keiichi Mochida
Team Leader
Bioproductivity Informatics Research Team