Ketocarotenoids (xanthophylls) such as astaxanthin and canthaxanthin have a potent antioxidation activity and exhibit a number of physiological effects including the suppression of lipid peroxidation, arteriosclerosis, inflammation and carcinogenesis. For the stable supply of these compounds, recent studies have been achieving to develop the microbial production systems using microalgae Haematococcus and yeast Phaffia. A new marine microorganism Schizochytrium sp. producing xanthophylls in addition to polyunsaturated fatty acids may be an alternative source for food additive and cultured fish food.

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Filamentous fungus, genus Mortierella has a high productivity of fatty acids, such as γ-linolenic acid.Mortierella alpina produces extraordinarily high percentages of arachidonic acid (AA), terminal metabolite of n-6 fatty acids, in intracellular lipids. The essential nutrients were organic nitrogen, minerals, and sugar. The highest AA contents and yields were 71.2% and 11.1g/L for liquid cultivation and 80.2% and 13.1g/kg-medium for solid cultivation, respectively. These results are attributed to neither high growth amounts nor high lipid contents of the fungus but to high activities in enzymes involved in chain elongation and (Δ9, Δ12, Δ6, Δ5) desaturases. Fungal form changed from pulp to pellets under starvation and high agitation with AA content increase until dying. In addition the fungus excreted prostaglandins (PGE₁, PGE₂, PGF_2α) over days in a liquid medium and also converted AA added in the medium to those prostaglandins. Thus, M. alpina shows the specificity of remarkable AA/PG productivities and is an interesting model for n-6 fatty acid metabolism.

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In order to design an injectable formulation of E5531, a novel synthetic disaccharide analog of lipid A, for the treatment of septic shock, a 'pH-jump method' was developed. In this method, E5531 was dispersed in 0.003 mol/L NaOH (pH 11.0, above pK_a2) at 50°C (above phase transition temperature) and then mixed with buffer to neutralize the pH 7.3. E5531 was dispersed as the particles and the size was approximately 20 nm. The membrane fluidity of the particles was correlated with the pharmacokinetics in rats and effective dose (ED₅₀) in BCG/LPS treatment mice.

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