Vol. 1 Issue 1
D. Alani, and G. Goma
The role of methanol, ethanol and sorbitol oleate on the growth of Candida lipolyrica on n-alkane substrate was studied by changing the concentrations of these solubilizing or emulsifying agents. These three substances enhanced the yeast growth at low concentration ranges, but beyond a critical concentration, exhibited inhibitory effects.
At an optimal concentration of solubilizing agent, the maximum growth rate was multiplied by 1,95 (CH30H), 1,9 (CH3CH20H) and 1,5 (sorbitol oleate). The stimulating effects may be due to increased solubility of n-alkane substrate. The modulization of the growth enhancement (E) with the concentration of the solubilizing agent (P) is performed.
Abou-Zeid A. Abou-Zeid, Ahmad O. Baghlaf, Jalaluldin A. Khan and Saleh S. Makhashin
Date seeds and cheese whey are mainly consisted of organic nitrogen sources, carbohydrates, lipids and minerals. These ingredients were utilized as natural medium for formation of citric acid by Candida lipolylica. Yield of citric acid was increased with the increase of fermentation period reaching its maximum at 96 hr. Yeast biomass was closely associated with citric acid formation. The best added carbon source was glucose which pushed the output of citric acid to high titres . The optimum concentration of glucose was 25 mg/ml. (NH4)2S04, NH4C1 and NR,NO) were used as inorganic nitrogen sources. The experimental organism preferred utilization of inorganic nitrogen sources in the form of ammonia rather than nitrate nitrogen. Addition of different concentrations of date seed ash into the medium increased the output of citric acid which reflected importance of certain elements present in date seed ash such as magnesium, iron, calcium, manganese, zinc and nickel in the biosynthetic formation of citric acid.
B.A.H. EI-Tawil
The test results of 173 species in a phytochemical screening program of Saudi plants are reported with data on alkaloids, leucoanthocyanidins, flavonoids , unsaturated sterols (or triterpenoids), cardiac glycosides, coumarins, and saponins. The plants represent 32 families. The results of phytochemical testing which gave high concentration (+ + +) are recorded and can be summarized in the following statements:
Alkaloids were detected in 23 species, leucoanthocyanidins in 13 species, nonsteroidal unsaturated compounds in 33 species, coumarins in 54 species and saponins in 11 species.