The effect of CO2 and salinity on the cultivation of Scenedesmus obliquus for biodiesel production

Biodiesel is a renewable and environmental friendly energy source that can be produced via tranesterification from various oil crops such as soy bean, sunflower, palm, and algae. In this work, the microalgae Scenedesmus obliquus, S. armatus and S. bernadii, isolated from natural water basins, were enriched in modified Chu 13 medium. Only S. obliquus showed significant oil accumulation and was thus further cultivated in 3 L tubular photo-reactors under mixotrophic conditions (16:8 h light-dark cycle) at room temperature and varying CO₂ (5, 10, and 15%) supply. The results indicated that S. obliquus can be grown under various CO₂ concentrations. A maximum biomass of 2.3 g/L was achieved when 15% CO₂ was used. The effect of salinity on oil storage was also considered, using sodium chloride (NaCl) solutions of varying concentrations (0.05, 0.2, and 0.3 M). Higher lipid contents were found in cells that were subjected to salt stress compared to those in conditions without salt stress. A maximum oil accumulation of 36% was observed within 15 days at 0.3 M NaCl. A biodiesel yield of up to 97.4% was obtained.     

Raised serum chondroitin sulfate epitope level in ovarian epithelial cancer

OBJECTIVE: To determine the value of serum chondroitin sulfate epitope WF6 and hyaluronan (HA) levels as a biomarker for early detection of ovarian epithelial cancer and other gynecological disorders. METHOD: Serum WF6 CS epitope and HA were measured in 91 patients with ovarian epithelial cancer, 39 patients with non-cancer gynecological disorders and 30 healthy women. Serum chondroitin sulfate (CS) WF6 epitope was determined by a competitive immunoassay with the monoclonal antibodies WF6, which specifically recognizes an epitope in native CS chains. In addition, serum HA concentration was measured by an ELISA-based assay with a biotinylated affinity HA-binding proteins. RESULTS: The serum concentration of CS (WF6) epitope was highly increased in epithelial types of ovarian cancer and at all stages of development (p < 0.005). Serum HA in ovarian cancer patients was significantly higher than normal controls (p < 0.05). CONCLUSION: These results reflect changes in ECM metabolism in progressive ovarian cancer, which cause an increase in serum CS epitopes and HA. Therefore, serum CS epitopes may provide useful biomarkers for cancers and other disorders of the ovary. Measurement of serum HA provided complementary information, which may be useful as a discriminator between benign ovarian disorders and malignant ovarian diseases.