Monday, July 25, 2011
Grand Ballroom, 5th fl (Sheraton New Orleans)
Biosurfactants (BS) are functional amphiphilic compounds produced by a variety of microorganisms from feedstock. They show unique properties (e.g., high biocompatibility, mild production conditions, and lower toxicity) compared to chemically synthesized counterparts. Mannosylerythritol lipids (MEL) are one of the most promising BS known, and are abundantly produced at yields of over 50 g/L from vegetable oils by yeast strains of the genus Pseudozyma. Cuttlefish oils are useful biomass, and contain polyunsaturated fatty acids (PUFA, e.g., 15 % of docosahexaenoic acid, C22:6, and 13% of eicosapentaenoic acid, C20:5). In order to evaluate the productivity of MEL from the oils, 12 strains of MEL producers were cultured using the oils as the sole carbon source. Consequently, 11 strains produced MEL from the oils except for one strain of P. tsukubaensis NBRC 1940. P. antarctica JCM 10317 showed the highest production yield of 17.5 g/L in a shake flask culture. Interestingly, the MEL produced by P. churashimaensis provided many peaks of PUFA on GC/MS analysis. Of these PUFA, the major acid (m/z = 262) was estimated to be hexadecatetraenoic acid (C16:4) based on its fragmentation pattern. P. churashimaensis produced 9.6 g/L of MEL including the tetraenoic acid from 50 g/L of cuttlefish oils for 7 d in a 1.5-L jar fermentor. Accordingly, P. churashimaensis is likely to have a great potential as a producer of highly functional MEL showing antioxidative activity.