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In the title compound, 1,3-dioxolane and 1,3-dioxole rings adopt envelope forms, while amide moiety and benzene ring are essentially planar. An intra­molecular O—H⋯O hydrogen bond supports the mol­ecular conformation, and inter­molecular weak C—H⋯O and C—H⋯π inter­actions connect the mol­ecules into sheet structure., In the title compound, C20H27NO6, the amide moiety is essentially planar, with a maximum deviation of 0.073 (3) Å, and one of the N-methyl groups shows rotational disorder. The five-membered 1,3-dioxolane ring adopts an envelope form, with the C atom bonded to the olefin side chain as the flap, which deviates from the mean plane through the other four atoms by 0.564 (7) Å. The 1,3-dioxole ring fused to the benzene ring adopts a flattened envelope form, with the C atom between the two O atoms as the flap, which deviates from the mean plane through the other four atoms by 0.215 (7) Å. The C—C=C—C olefin moiety is essentially planar and makes a dihedral angle of 87.1 (3)° with the benzene ring. An intra­molecular O—H⋯O hydrogen bond supports the mol­ecular conformation, enclosing an S(11) graph-set motif. In the crystal, inter­molecular C—H⋯O hydrogen bonding links the mol­ecules into a tape running along the b axis. Furthermore, other weak C—H⋯O hydrogen bonds and a C—H⋯π inter­action connect the tapes into a sheet structure parallel to (100).

The use of fast-growing oleaginous algal strains is indispensable to achieve low-cost production system for microalgal biodiesel. We therefore previously isolated a new algal species within new genus "Pseudochoricystisas" (invalid name, class Trebouxiophyceae), "Pseudochoricystis ellipsoidea" (MBIC11204), which possesses oil vesicles stainable with a selective fluorescent dye for intracellular lipid droplets, Nile Red (Sekiguchi et al., 12th Annu. Meet. Jpn. Microbiol. Cult. Coll. 2005). In the present study we attempted to investigate growth and lipid accumulation of this new isolate. The maximum growth rate of P. ellipsoidea was 3.46 g dry weight l-1 day-1. Nile Red fluorescence reached maximum intensity within 5-10 days after transferring P. ellipsoidea cells to nitrogen starvation conditions in the light, but not in the dark. Total lipid content made up 32% of normal-grown (+N) and 26% of nitrogen-starved (-N, 8 days) dry weight algal cells, and the hydrocarbon fraction was more than 10 times higher in -N cells. Fatty acid composition changes and an increase in triglycerides to 82% of total lipid were also observed with nitrogen starvation. These results suggest that P. ellipsoidea is a fast-growing oleaginous algal strain in which hydrocarbons and triglycerides can be produced photoautotrophically up to 30% of the dried biomass.