Enhanced fatty acid accumulation in Isochrysis galbana by inhibition of the mitochondrial alternative oxidase pathway under nitrogen deprivation

• Published in: Bioresource technology 2016-07, Vol.211, p.783-786
• Main Authors: Zhang, Litao, Liu, Jianguo
• Format: Article
• Language: English
• Subjects: Alternative oxidase; Fatty acid accumulation; Fatty Acids - metabolism; Haptophyta - metabolism; Mitochondrial Proteins - metabolism; Nitrogen - chemistry; Nitrogen - metabolism; Nitrogen deprivation; Oxidoreductases - metabolism; Plant Proteins - metabolism; Reducing equivalents
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2016.03.164

•N deprivation increased the mitochondrial AOX pathway activity in I. galbana.•N deprivation significantly increased the fatty acid accumulation.•The inhibition of AOX pathway caused the accumulation of reducing equivalents.•The inhibition of AOX pathway further enhanced the fatty acid accumulation. The purpose of this study was to clarify the interrelation between the mitochondrial alternative oxidase (AOX) pathway and fatty acid accumulation in marine microalga Isochrysis galbana. Under normal conditions, the activity of the AOX pathway was maintained at a low level in I. galbana. Compared with the normal condition, nitrogen deprivation significantly increased the AOX pathway activity and fatty acid accumulation. Under nitrogen deprivation, the inhibition of the AOX pathway by salicylhydroxamic acid caused the accumulation of reducing equivalents and the over-reduction of chloroplasts in I. galbana cells, leading to a decrease in the photosynthetic O2 evolution rate. The over-production of reducing equivalents due to the inhibition of the AOX pathway under nitrogen deprivation further enhanced the accumulation of fatty acids in I. galbana cells.