Dynamic metabolic profiling together with transcription analysis reveals salinity-induced starch-to-lipid biosynthesis in alga Chlamydomonas sp. JSC4

• Published in: Scientific reports 2017-04, Vol.7 (1), p.45471-45471, Article 45471
• Main Authors: Ho, Shih-Hsin, Nakanishi, Akihito, Kato, Yuichi, Yamasaki, Hiroaki, Chang, Jo-Shu, Misawa, Naomi, Hirose, Yuu, Minagawa, Jun, Hasunuma, Tomohisa, Kondo, Akihiko
• Format: Article
• Language: English
• Subjects: 45/23; 631/449/906/4052; 631/45/320; 631/61/320; 82/16; 82/29; 82/58; Acetaldehyde dehydrogenase; Acetyl Coenzyme A - metabolism; Acetyl-CoA carboxylase; Acetyl-CoA Carboxylase - genetics; Acetyl-CoA Carboxylase - metabolism; Algae; Aquatic microorganisms; Biofuels; Biomass; Biosynthesis; Carbon - metabolism; Chlamydomonas; Chlamydomonas - metabolism; Ferredoxin; Gene Expression Profiling; Genetic engineering; Humanities and Social Sciences; Lipid metabolism; Lipid Metabolism - drug effects; Lipids; Lipids - analysis; Metabolic rate; Metabolism; Metabolomics; multidisciplinary; Oxidoreductase; Pyruvate decarboxylase; Pyruvate Decarboxylase - genetics; Pyruvate Decarboxylase - metabolism; Pyruvic acid; Pyruvic Acid - metabolism; Salinity; Salinity effects; Salts - pharmacology; Science; Starch - metabolism; Starch Phosphorylase - genetics; Starch Phosphorylase - metabolism
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep45471

Biodiesel production using microalgae would play a pivotal role in satisfying future global energy demands. Understanding of lipid metabolism in microalgae is important to isolate oleaginous strain capable of overproducing lipids. It has been reported that reducing starch biosynthesis can enhance lipid accumulation. However, the metabolic mechanism controlling carbon partitioning from starch to lipids in microalgae remains unclear, thus complicating the genetic engineering of algal strains. We here used “dynamic” metabolic profiling and essential transcription analysis of the oleaginous green alga Chlamydomonas sp. JSC4 for the first time to demonstrate the switching mechanisms from starch to lipid synthesis using salinity as a regulator, and identified the metabolic rate-limiting step for enhancing lipid accumulation ( e.g. , pyruvate-to-acetyl-CoA). These results, showing salinity-induced starch-to-lipid biosynthesis, will help increase our understanding of dynamic carbon partitioning in oleaginous microalgae. Moreover, we successfully determined the changes of several key lipid-synthesis-related genes ( e.g. , acetyl-CoA carboxylase, pyruvate decarboxylase, acetaldehyde dehydrogenase, acetyl-CoA synthetase and pyruvate ferredoxin oxidoreductase) and starch-degradation related genes ( e.g. , starch phosphorylases), which could provide a breakthrough in the marine microalgal production of biodiesel.