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 120 min. 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.

Effect of encapsulation of mefenamic acid with cationic Eudragit E on its bioavailability and gastric ulcerogenic activity in rabbits

Encapsulation of mefenamic acid (MFA), a potent non-steroidal anti-inflammatory drug with cationic acrylic resin, Eudragit E, was carried out using a fluidized-bed granulator (Glatt AG). Three drug:polymer ratios were prepared using 50 ml of 1, 2.5 and 5 per cent w/v aqueous suspension of Eudragit to coat 100 mg powdered drug. The bioavailability of the coated and uncoated drug was studied using four groups of animals, each consisting of six male rabbits (2-2.5 kg). Investigations were performed using the rabbits to examine the effects of prolonged administration of the coated and the uncoated MFA with Eudragit E(1 and 5 per cent) in a dose of 100 mg filled in hard gelatin capsules. One capsule was given daily for 30 days. Plasma levels of MFA with Eudragit E were significantly higher than those of drug only. Meanwhile, 5 per cent w/v polymer coating afforded higher drug availability than 2.5 per cent w/v which induced a higher level than 1 per cent w/v. Chronic gastric ulcers with different severities were found in the internal mucosa of all animals. In addition, there were multiple erosions in the glandular mucosa of stomachs of rabbits receiving MFA within the treatment period. IN the control group the gastric photograph was normal in every instance. Despite the extensive morphological damage at the end of treatment, the observed changes in the stomach of rabbits given coated drug is less deleterious than that treated with uncoated drug. The results of this study indicate that the coating of MFA with cationic Eudragit E increases its bioavailability and decreases the probability of ulceration.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on protein production by yeasts. III. Effects of different levels of nitrogen and phosphorus

The four strains of yeasts that gave good growth in molasses medium, short generation time, and high protein content were selected for further studies in a trial for increasing their yield and protein content. Therefore, the effect of different levels of ammonium sulphate and potassium dihydrogen phosphate on the growth and protein synthesis of the strains was investigated, using molasses as a source of carbon. The results revealed that the most suitable concentrations of ammonium sulphate in the propagation medium lie between 0.40 to 0.55% for the production of high yield and protein content of strains S. cerevisiae (Gr. 104), C. utilis (F. 86), C. tropicalis (F. 35), and H. anomala (Gr. 5). The optimum concentration of potassium dihydrogen phosphate lies between 0.2 to 0.3% for the same strains. S. cerevisiae (Gr. 104) seemed to be the most efficient strain that gave the best growth, high percentage of protein, and essential amino acids in molasses medium.

Studies on protein production by yeasts. IV. Incremental feeding modulus

S. cerevisiae Gr. 104 which seemed to be the most efficient strain in protein production, was used for investigating its optimum incremental feeding modulus that gives the highest economical yield. Therefore, different hourly rates of incremental feeding, ranging from 1.14 to 1.22, were used and the yeast yield for each rate was determined. Experiments were carried out in a laboratory fermentor vessel of 5 liter capacity, using molasses, ammonium sulphate, and potassium dihydrogen phosphate as feeding substances with optimum pH, temperature, and effective aeration. The optimum incremental feeding for this strain (which is the rate of molasses feeding corresponding to the exponential growth rate) was found to be 1.18. At this rate the best economical use of the substrate was obtained with the production of yield, close to the theoretically calculated yield.

Studies on protein production by yeasts. I. Isolation, identification, and screening of efficient strains

A collection of yeast strains was isolated from different fresh fruits and foodstuffs. Isolates were purified and completely identified up to the species. The ninety isolated yeast strains were screened according to their yield and total nitrogen content, using molasses medium as an available cheap raw-material for yeast propagation.