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With the aim of solubilizing R-phycoerythrin from Grateloupia turuturu, we tested the efficiency of two extraction solutions (distilled water and phosphate buffer) on fresh and freeze-dried seaweeds. Three different methods enabling a partial purification of this pigment were also tested: ammonium sulfate precipitation, separation in aqueous two-phase systems, and ultrafiltration. The best extraction and partial purification conditions for R-phycoerythrin were observed from freeze-dried algae after application of the precipitation procedure (80% ammonium sulfate). This latter protocol appears to be efficient for separating R-phycoerythrin without denaturation from most proteins and other components (such as sugars) that limit the purification of phycobiliproteins.

The extraction of metabolites of industrial interest from seaweed tissue is difficult due to the presence of anionic polysaccharides in the cell walls. We studied enzymatic digestion of Grateloupia turuturu (Rhodophyta) to facilitate extraction of the desired metabolites from this seaweed. Four polysaccharidases (Onozuka R-10 cellulase, agarase, κ- and ι-carrageenases) were used alone and in combination. We studied the efficiency of the enzymatic process in degrading the seaweed thallus; we also investigated the effect of the enzymatic treatment on solubilization of R-phycoerythrin and reducing sugars. The best degradation conditions for Grateloupia thalli were obtained with cellulase alone (0.48 U ml-1), or with a combination of cellulase/κ-carrageenase. However, only the combination cellulase (0.08 U ml-1)/κ-carrageenase (0.01 U ml-1), or the individual enzymes [agarase or ι-carrageenase at low concentration (0.55 U ml-1 and 2.5×10-3 U ml-1)] improved solubilization of R-phycoerythrin compared to the control conditions. The simultaneous use of polysaccharidases enabled solubilization of a large quantity of reducing sugars (40 mg glu g-1 dw). Therefore, this condition appears suitable for the production of oligosaccharides. This result also confirms indirectly the presence of agar, cellulose, κ- and ι-carrageenans in the cell wall of Grateloupia turuturu.

The phospholipid fatty acid composition of the North-East Atlantic sponge Polymastia penicillus (South Brittany, France) was investigated. Sixty fatty acids (FA) were identified as methyl esters (FAME) and N-acyl pyrrolidides (NAP) by gas chromatography-mass spectrometry (GC/MS), including eight Delta5,9 unsaturated FA and three long-chain 2-hydroxylated FA. The major phospholipid FA were palmitic (14.3% of the total FA mixture), vaccenic (12.7%), 15(Z)-docosenoic (13.4%) and 5(Z),9(Z)-hexacosadienoic (13.3%) acids. In addition to the iso- and anteiso-branched saturated FA, several unusual short-chain branched saturated FA were identified. In addition to the known Delta5,9 FA, and interestingly regarding their identification by GC-MS as N-acyl pyrrolidides, was the co-occurrence of unusual FA possessing a Delta3, Delta4 and Delta5 double bond such as iso-4-pentadecenoic, iso-5-heptadecenoic, anteiso-5-heptadecenoic and two new compounds, not hitherto found in nature, namely 17-methyl-13-octadecenoic (0.8%) and 3,16-docosadienoic (1.1%) acids.