Microalgae sterols

Volkman, J.K., Barrett, S.M., and Blackburn, S.I. (1999) Eustigmatophyte microalgae are potential sources of C29 sterols, n-C23- -C28 n-alkanols and C28-C32 n-alkyl diols in freshwater environments. Org. Geochem. 30, 307-318. 

Sterols with the stigmastane skeleton (C29) (66c) typically occur in higher plants (Volkman, 1986), but are also the major sterols in many microalgae, such as several freshwater eustigmatophytes and chrysophytes, and green algae of the class Chlorophyceae. Unfortunately, the C27 to C29 desmethylsteranes are not characteristic for any specific taxon, because the precursors are widely distributed in the domain Eukarya. Even related species within the same class may contain major sterols with different carbon numbers or even mixmres of all three carbon skeletons (Volkman, 1986, 2003, 1980). 

All microalgae contain sterols (typically up to 10% of total lipid) either as the free sterol (most common) or as a fatty acid ester, glycoside or sulphate (Ghosh et /., 1998 Volkman et al, 1998 Milke et al, 2008). Sterol profiles can be characteristic of a particular class, family, genus or even species and so are often applied to chemotaxonomic and phylogenetic studies. Profiles... 

Bivalves have a limited capacity to synthesize sterols de novo (Holden and Patterson, 1991) so dietary sterols from microalgae could be important in their nutrition. For post-larval P. magellanicus, the combination of C muelleri with Pavlova spp. produced higher growth rates than other algal diets tested, which was attributed to the comparatively high proportion of cholesterol in sterols from C. muelleri (Milke et al, 2008). Of the other... 

Generally, microalgae lipids include nentral lipids, polar lipids, wax esters, sterols, and hydrocarbons, as well as phenyl derivatives (Naik et al, 2010). For biodiesel prodnction, natural lipids, which are nonpolar, are always targeted. Typically, most of the lipids produced from microalgae strains that have been tested for biodiesel prodnction have fatty acid constitutions similar to most common vegetable oils (Becker, 2004 Huang et al., 2012), as shown in Table 6.1. 

Sterols are among the most important chemical constituents of micro- and macroalgae and a major nutritional component in the diet of aquacultured organisms. Microalgae are important components in the diet ofmany hydrobionts, especially bivalves... 

The quahtative and quantitative sterol composition of microalgae used in hatcheries has direct imphcations in the phytosterol and cholesterol (8) composition of bivalve larvae and can affect their growth performance. 

Ponomarenko, L.P. et al. (2004) Sterols of marine microalgae Pyramimonas cf cordata (prasinophyta), Atteya ussurensis sp. nov. (Bacollariophyta) and a spring diatom bloom form Lake Baikal. Comp. Biochem. Physiol. B. 138, 65-70... 

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