Presentation Information
[P04-545]Development of enhanced oil producer in the marine green alga Marinichlorella sp. NKG400014 by adaptive laboratory evolution
○Kanatsu Shibata1, Ryota Kumakubo1, Kousuke Kataoka1,2, Tsuyoshi Tanaka1 (1. Tokyo university of agriculture and technology (Japan), 2. Comprehensive Research Organization, Waseda University (Japan))
Keywords:
Marine green microalgae,Oxidative stress,Stress tolerance,Adaptive Laboratory Evolution
[Purpose]
Microalgae are promising production hosts for sustainable aviation fuel (SAF) because of their rapid growth and high CO2 fixation capacity. However, large-scale outdoor cultivation exposes cells to fluctuating environmental stresses that markedly reduce productivity. The development of stress-tolerant strains is therefore essential for stable biomass and oil production. Adaptive laboratory evolution (ALE) is a non-genetically modified (non-GMO) breeding approach in which populations are repeatedly subcultured under defined selective pressure to accumulate beneficial phenotypes. In this study, ALE under oxidative stress was applied to the oil-producing marine green alga Marinichlorella sp. NKG400014 to obtain oxidative-stress-tolerant strains and to evaluate their growth and oil-producing characteristics.
[Method]
Marinichlorella sp. NKG400014 cells were cultivated for an extended period under oxidative stress conditions with gradually intensified selective pressure. After the evolution period, the evolved population was plated, and multiple independent clones were isolated. These clones were screened for growth under oxidative stress. A strain exhibiting stable growth under oxidative stress was selected. Growth characteristics of the selected strain (ALE strain) were further evaluated under various conditions. Photosynthetic activity and pigment composition were also analyzed to assess physiological changes associated with the acquired phenotype.
[Results and discussion]
Cells were repeatedly subcultured in liquid medium under oxidative stress for 120 days. After the evolution period, several independent clones were randomly selected. Among them, an ALE strain was identified as the only clone that exhibited stable growth under oxidative stress. Strain NKG400014 wild type (WT) exhibited marked growth inhibition under oxidative stress, whereas ALE16-1 maintained growth. These results confirmed that ALE16-1 acquired enhanced tolerance to oxidative stress. Furthermore, ALE16-1 showed higher oil content and productivity than WT. Changes in Fv/Fm and non-photochemical quenching (NPQ) were also observed. Therefore, physiological changes may be associated with excitation energy utilization under stress conditions, although the precise mechanisms remain to be clarified.
[Conclusion]
ALE generated the strain, which exhibited enhanced oxidative-stress tolerance, and oil production. These findings demonstrate that ALE is a useful non-GMO strategy for developing robust microalgal strains suitable for outdoor biomass and oil production.
Microalgae are promising production hosts for sustainable aviation fuel (SAF) because of their rapid growth and high CO2 fixation capacity. However, large-scale outdoor cultivation exposes cells to fluctuating environmental stresses that markedly reduce productivity. The development of stress-tolerant strains is therefore essential for stable biomass and oil production. Adaptive laboratory evolution (ALE) is a non-genetically modified (non-GMO) breeding approach in which populations are repeatedly subcultured under defined selective pressure to accumulate beneficial phenotypes. In this study, ALE under oxidative stress was applied to the oil-producing marine green alga Marinichlorella sp. NKG400014 to obtain oxidative-stress-tolerant strains and to evaluate their growth and oil-producing characteristics.
[Method]
Marinichlorella sp. NKG400014 cells were cultivated for an extended period under oxidative stress conditions with gradually intensified selective pressure. After the evolution period, the evolved population was plated, and multiple independent clones were isolated. These clones were screened for growth under oxidative stress. A strain exhibiting stable growth under oxidative stress was selected. Growth characteristics of the selected strain (ALE strain) were further evaluated under various conditions. Photosynthetic activity and pigment composition were also analyzed to assess physiological changes associated with the acquired phenotype.
[Results and discussion]
Cells were repeatedly subcultured in liquid medium under oxidative stress for 120 days. After the evolution period, several independent clones were randomly selected. Among them, an ALE strain was identified as the only clone that exhibited stable growth under oxidative stress. Strain NKG400014 wild type (WT) exhibited marked growth inhibition under oxidative stress, whereas ALE16-1 maintained growth. These results confirmed that ALE16-1 acquired enhanced tolerance to oxidative stress. Furthermore, ALE16-1 showed higher oil content and productivity than WT. Changes in Fv/Fm and non-photochemical quenching (NPQ) were also observed. Therefore, physiological changes may be associated with excitation energy utilization under stress conditions, although the precise mechanisms remain to be clarified.
[Conclusion]
ALE generated the strain, which exhibited enhanced oxidative-stress tolerance, and oil production. These findings demonstrate that ALE is a useful non-GMO strategy for developing robust microalgal strains suitable for outdoor biomass and oil production.
Comment
To browse or post comments, you must log in.Log in