Evolutionary engineering of salt-resistant Chlamydomonas sp. strains reveals salinity stress-activated starch-to-lipid biosynthesis switching. (December 2017)

• Record Type: Journal Article
• Authors: Kato, Yuichi; Ho, Shih-Hsin; Vavricka, Christopher J.; Chang, Jo-Shu; Hasunuma, Tomohisa; Kondo, Akihiko
• Is Part Of: Bioresource technology. Volume 245:Part B(2017)
• Page Start: 1484
• Page End: 1490
• Publication Date: 2017-12
• Subjects: Biofuels -- Evolutionary breeding -- Microalgae -- Salinity stress; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2017.06.035
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: Bred microalga Chlamydomonas sp. strains resistant to 7% sea salt. Starch-to-lipid biosynthesis switching was inactivated, and lipid content was decreased. Salinity stress was significantly relieved in the resistant strains. Salinity stress, not salinity condition itself, would be required for lipid accumulation. Abstract: The aim of this study was to improve biomass production of the green microalga Chlamydomonas sp. JSC4 under high salinity conditions. For this purpose, heavy ion beam-coupled mutagenesis and evolutionary engineering were performed using JSC4 as the parent strain. After long-term and continuous cultivation with high salinity, salt-resistant strains that grow well even in the presence of 7% sea salt were successfully obtained. Transcriptional analysis revealed inactivation of starch-to-lipid biosynthesis switching, which resulted in delayed starch degradation and decreased lipid content in the salt-resistant strains. Cellular aggregation and hypertrophy during high salinity were relieved in these strains, indicating strong resistance to salt stress. These results suggest that high salinity stress, not the salinity condition itself, is important for activating lipid accumulation mechanisms in microalgae.