α/β hydrolase domain-containing protein 1 acts as a lysolipid lipase and is involved in lipid droplet formation.

Lipid droplets (LDs) are the major sites of lipid and energy homeostasis. However, few LD biogenesis proteins have been identified. Using model microalga , we show that ABHD1, an α/β-hydrolase domain-containing protein, is localized to the LD surface and stimulates LD formation through two actions: one enzymatic and one structural.

Hydrogen isotope fractionation is controlled by CO in coccolithophore lipids.

Hydrogen isotope ratios (δH) represent an important natural tracer of metabolic processes, but quantitative models of processes controlling H-fractionation in aquatic photosynthetic organisms are lacking. Here, we elucidate the underlying physiological controls of H/H fractionation in algal lipids by systematically manipulating temperature, light, and CO(aq) in continuous cultures of the haptophyte . We analyze the hydrogen isotope fractionation in alkenones (α), a class of acyl lipids specific to this species and other haptophyte algae.

Branched-Chain Amino Acid Catabolism Impacts Triacylglycerol Homeostasis in .

Nitrogen (N) starvation-induced triacylglycerol (TAG) synthesis, and its complex relationship with starch metabolism in algal cells, has been intensively studied; however, few studies have examined the interaction between amino acid metabolism and TAG biosynthesis. Here, via a forward genetic screen for TAG homeostasis, we isolated a () mutant () that is deficient in the E1α subunit of the branched-chain ketoacid dehydrogenase (BCKDH) complex. Metabolomics analysis revealed a defect in the catabolism of branched-chain amino acids in Furthermore, this mutant accumulated 30% less TAG than the parental strain during N starvation and was compromised in TAG remobilization upon N resupply.

Lipid catabolism in microalgae.

Lipid degradation processes are important in microalgae because survival and growth of microalgal cells under fluctuating environmental conditions require permanent remodeling or turnover of membrane lipids as well as rapid mobilization of storage lipids. Lipid catabolism comprises two major spatially and temporarily separated steps, namely lipolysis, which releases fatty acids and head groups and is catalyzed by lipases at membranes or lipid droplets, and degradation of fatty acids to acetyl-CoA, which occurs in peroxisomes through the β-oxidation pathway in green microalgae, and can sometimes occur in mitochondria in some other algal species. Here we review the current knowledge on the enzymes and regulatory proteins involved in lipolysis and peroxisomal β-oxidation and highlight gaps in our understanding of lipid degradation pathways in microalgae.

Evolution of a Biomass-Fermenting Bacterium To Resist Lignin Phenolics.

Increasing the resistance of plant-fermenting bacteria to lignocellulosic inhibitors is useful to understand microbial adaptation and to develop candidate strains for consolidated bioprocessing. Here, we study and improve inhibitor resistance in (also called ), a model anaerobe that ferments lignocellulosic biomass. We survey the resistance of this bacterium to a panel of biomass inhibitors and then evolve strains that grow in increasing concentrations of the lignin phenolic, ferulic acid, by automated, long-term growth selection in an anaerobic GM3 automat.