In this study, human-safe lactic acid microorganisms (LAM) were isolated from food samples to be used as potential additives for human food. Samples from various food sources (artisanal cheeses, fermented chickpeas, fermented rice, natural yogurt, pickles, and raw milk) were used to inoculate de Man, Rogosa, and Sharpe (MRS) and malt agar plates, which were incubated at 30°C for 48 h or 37°C for 72 h to isolate lactic acid bacteria and yeast, respectively. Out of 120 isolates (85 bacteria and 35 yeast), 75 isolates showed γ-hemolytic activity and were considered “Generally Recognized As Safe” (GRAS) isolates. After testing their growth rate under the gastrointestinal tract (GIT) conditions, including acidic pH and specific bile salt concentrations, we selected 30 isolates. Then, we evaluated the fermentative abilities of these 30 isolates on nine types of carbohydrates, their total acidity, and their antagonistic activity against five human pathogens. Based on the results of these tests, four isolates were selected for identification using the Biolog program and 16S rRNA sequencing for bacteria and 18S rRNA sequencing for yeast and found to be Bacillus bingmayongesis (FJAT-13831), Lacticaseibacillus paracasei (R094), Pediococcus pentosaceus (DSM 20336), and one yeast isolate as Saccharomyces cerevisiae (SaCe1 26S).

Four agro-wastes were evaluated as substrates for bioethanol production. Seven of the pioneer isolates in the production of cellulase, xylanase and laccase enzymes were selected for soluble sugar and bioethanol production. The highest level of soluble sugar was produced on sugar beet pulp followed by corn cobs. The experimental design included using soybean okara and sesame husk as nitrogen sources added to the production medium. Extraordinary soluble sugar yields were obtained on sugar beet pulp or corn cobs in combination with soybean okara or sesame husk at the concentration of (0.3%) of either. Different concentrations of corn cobs or sugar beet (5, 10, 15, g/100 m medium) were mixed with optimal concentrations of nitrogen sources. Results showed that 10 g of sugar beet or corn cobs achieved the highest soluble sugar yield. The efficiency of four strains of S. cerevisiae for bioethanol production was investigated, S.cerevisiae (AUMC 14720) recorded the highest level of bioethanol on fermentable fungal broth after four days at 30°C.

Our study was carried out at the farm of Faculty of Agriculture, Ain Shams University, Egypt. The average temperatures were 18.4°C and 23.9 °C from December 2017 - February 2018 to study the effects of Saccharomycescerevisiaeboulardii supplementation (as feed additives) on productive performance of growing rabbits. Sixty growing rabbits of the NZW (New Zealand White Rabbits), (4 weeks old) and weighted (603.62 gm mean body weight) were randomly distributed into 4 treated groups, n=15 rabbits per each group. Rabbits of supplemented groups were given 100 (R1), 200 (R2) and 400 (R3) gm/ton feed of Saccharomyces cerevisiaeboulardii mixed in the diet for 6 successive weeks. Individual live body weight was noted weekly from start till the end of the experiment. At the end of the experimental period, 10 rabbits (from each group) were fasting for 12 hrs, then slaughtered for carcass traits measure. Experimental lighting system was 16-hours photoperiod /day (16L: 8D) through both daily natural and the artificial fluorescent lighting. A pelleted ration of 17.3% crude protein, 13.37% crude fiber and 2510 kcal of digestible energy per kg feed was offered ad libitum all the time. Results revealed significant (P≤0.05) increases in the final body weight and daily weight gain with saccharomyces cerevisiae supplementation when compared with control group. Though, significantly (P≤0.05) improved feed conversion ratio in all treated groups compared with control one were noticed. Feed intake was the lower in treated groups than control group. There were significant (P≤0.05) increasing in hot carcass weight and carcass percentage with respect to the control group. Supplemented Saccharomycescerevisiae reduced (P≤0.05) the liver, heart, lungs and kidneys percentages compared the control group. Supplemented rabbit feeds with saccharomycescerevisiaeboulardii in their diets had highly increasing in relative economic efficiency and clear improvement of net revenue than control group.

All living organisms are subjected to changing in conservational conditions, to which they must adapt to. Stress is defined as a threat refers to the physiological balance of systems critical to survival organisms. Five yeast strains (Saccharomyces cerevisiae) were subjected to different adverse environmental situations, such as thermal, osmotic and oxidative (salt) stresses. The objective of this work was to detect the most tolerant yeast strains under salt or heat stresses.  Five yeast strains were exposed in a first experiment to heat stress at 20°C or 40°C beside to the control at 30°C to detect the more tolerant strain. The same yeast strains were subjected in a second experiment to two different concentrations of salt stress (NaCl); 0.5 or 1.0 M, separately, for two days (at 30°C as normal temperature for growth), other strains were exposed to 0.5 M concentration of NaCl for 24 hours, then 1 M for another 24 hours. For the heat stress results, strain S4 was more tolerant at 40oCwith insignificant difference compared to the control (30oC), while it showed significant difference at 20°C. Strain S5 also was more tolerant at 20oC with insignificant difference compared to the control. For salt treatment, the only insignificant value was for strain S3at 0.5M NaCl compared with the control.