Project description:Volatile fatty acids found in effluents of the dark fermentation of biowastes can be used for mixotrophic growth of microalgae, improving productivity and reducing the cost of the feedstock. Microalgae can use the acetate in the effluents very well, but butyrate is poorly assimilated and can inhibit growth above 1 gC.L-1. The non-photosynthetic chlorophyte alga Polytomella sp. SAG 198.80 was found to be able to assimilate butyrate fast. To decipher the metabolic pathways implicated in butyrate assimilation, a large-scale differential proteomics study was developed comparing Polytomella sp. cells grown on acetate and butyrate at 1 gC.L-1.
Project description:The unicellular, free-living, nonphotosynthetic chlorophycean alga Polytomella parva, closely related to Chlamydomonas reinhardtii and Volvox carteri, contains colorless, starch-storing plastids. The P. parva plastids lack all light-dependent processes but maintain crucial metabolic pathways. The colorless alga also lacks a plastid genome, meaning no transcription or translation should occur inside the organelle. Here, using an algal fraction enriched in plastids as well as publicly available transcriptome data, we provide a proteomic characterization of the P. parva plastid, ultimately identifying several plastid proteins, both by mass spectrometry and bioinformatic analyses. Altogether these results led us to propose a plastid proteome for P. parva, i.e., a set of proteins that participate in carbohydrate metabolism; in the synthesis and degradation of starch, amino acids and lipids; in the biosynthesis of terpenoids and tetrapyrroles; in solute transport and protein translocation; and in redox homeostasis. This is the first detailed plastid proteome from a unicellular, free-living colorless alga.
