Factors Affecting Microbial Oil Accumulation by Oleaginous Yeast

The growth performance and intracellular lipid production potentiality of two identified yeast stains Candida tropicalis (S5) and Issatchenkia orientalis (D5) in N-limited medium under different carbon, nitrogen sources, carbon/nitrogen ratio and temperature was studied. Among all carbon sources, glucose was the best in lipid weight, lipid content, lipid yield and lipid productivity. The increases in cell biomass reached its maximum value by use of yeast extract in Candida (8.62 gL-1) and 10.25 gL-1 for Issatchenkia using peptone. However, urea was the preferable N source for lipid production in both strains. On the other hand, KNO3 proved to be the lowest values treatment in the cell biomass and lipid production for both strains. The interaction treatments yeast extract + (NH4) SO4 was convenient for oil yield parameters in Candida. The data showed that the maximum cell biomass was obtained at 54 and 100 C/N ratio for Candida and Issatchenkia, respectively. The data also exhibited that designated sharp increases in lipid weight, lipid content and lipid productivity were developed by the two yeast strains reached their maximum values at C/N ratio 115 (1.0 gL-1, 27.77%, 0.20 gL-1) for Candida tropicalis and C/N ratio 100 (3.37 gL-1, 30.92%, 0.67 gL-1) for Issatchenkia orientalis. Further increase in C/N ratio resulted in drop in lipid weight; this drop was slight in Candida above 115, whereas it was drastically in Issatchenkia after C/N 100. The result of effect of temperature degree on cell biomass and lipid production showed that the temperature degree of 30°C was the best for yeast growth and also for lipid production.

Microbial Oil Production under Optimum Condition by Oleaginous Yeast

Two oleaginous yeast strains identified as Issatchenkia orientalis D5 and Candida tropicalis S5 were evaluated for oil production under optimized growth factors. Both strains were inoculated in 2L of optimal fermentation broth medium for 9 days. Sample was taken periodically (24 hrs.), The data exhibited that cell biomass was gradually increased along with time sample to reach maximum values of cell dry weight (11.22 & 13.30 gL-1) after 8 and 9 day at consumed sugar equal to 79.52 and 156.29 gL-1 for Candida  and Issatchenkia. It was found that Candida gave the highest values of lipid weight, lipid content, lipid yield, conversion coefficient and lipid productivity after 6 days being 2.16 gL-1, 34.17%, 2.70%, 2.73% and 0.36 gL-1/day, while Issatchenkia recorded the highest lipid concentration and lipid yield after 4 days of the fermentation period being 3.24 gL-1 and 2.06%. The specific growth rate, doubling time, multiplication rate and number of generation were 0.317 day-1, 2.18 days, 0.458 day-1 and 1.37 for Candida and reached to 0.275 day-1, 2.52 days, 0.396 day-1 and  0.793 for Issatchenkia. The data proved that the strains Issatchenkia orientals and Candida tropicalis could be used as feedstock producers for microbial lipid production.

Effect of acid hydrolysis and fungal biotreatment on agro-industrial wastes for obtainment of free sugars for bioethanol production

This study was designed to evaluate selected chemical and microbiological treatments for the conversion of certain local agro-industrial wastes (rice straw, corn stalks, sawdust, sugar beet waste and sugarcane bagasse) to ethanol. The chemical composition of these feedstocks was determined. Conversion of wastes to free sugars by acid hydrolysis varied from one treatment to another. In single-stage dilute acid hydrolysis, increasing acid concentration from 1 % (v/v) to 5 % (v/v) decreased the conversion percentage of almost all treated agro-industrial wastes. Lower conversion percentages for some treatments were obtained when increasing the residence time from 90 to 120min. The two-stage dilute acid hydrolysis by phosphoric acid (1.0 % v/v) followed by sulphuric acid (1.0 % v/v) resulted in the highest conversion percentage (41.3 % w/w) on treated sugar beet waste. This treatment when neutralized, amended with some nutrients and inoculated with baker's yeast, achieved the highest ethanol concentration (1.0 % v/v). Formation of furfural and hydroxymethylfurfural (HMF) were functions of type of acid hydrolysis, acid concentration, residence time and feedstock type. The highest bioconversion of 5 % wastes (37.8 % w/w) was recorded on sugar beet waste by Trichoderma viride EMCC 107. This treatment when followed by baker's yeast fermentation, 0.41 % (v/v) ethanol and 8.2 % (v/w) conversion coefficient were obtained.

Formulation and evaluation of novel mucoadhesive ketorolac tromethamine liquid suppository

Ketorolac tromethamine (KT) loaded mucoadhesive liquid suppository was prepared as a site-specific mucoadhesive rectal dosage form. Poloxamer mixture formed of 21P407 and 9P188 were used as liquid suppository base. In-vitro release rate of KT from liquid suppository was studied and compared to that from conventional suppository. The safety of the prepared suppository on GIT was conducted; hepatotoxicity of KT after 5 days of administration of liquid suppository was evaluated histologically and biochemically. The levels of liver enzymes alanine aminotransferase (ALT); aspartate amino transferase (AST); alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were used as the biochemical markers of liver damage. The results obtained revealed that the addition of KT increased the gelation temperature of poloxamer gel and reduced the gel strength and the mucoadhesive force. The study of the release rate of KT from liquid suppository was significantly higher than from conventional suppositories. Histological pictures of the GI tissues indicated no pathological damage after 5 days of rectal administration compared to oral administration. Also; it was revealed that no hepato-cellular damage occurred after administration of liquid suppository; unlike oral administration; which produced certain hepato-toxicity. The administration of KT liquid suppository did not significantly increase the basic levels of ALT and AST when compared to the control. On the other hand; the administration of KT oral solution in a dose of 10 mg/kg body weight/day for 5 days significantly increased serum ALT and AST levels; thus; KT liquid suppository in poloxamer gel was a convenient; safe and effective rectal dosage form for administration with lower hepato-toxic effect