This study intended to determine the ability of endophytic bacteria recovered from root nodules of Cicer arietinum L. and Vigna unguiculata L. (Walp.) plants to synthesize exopolysaccharide (EPS) and to enhance the production by changing nutritional factors. Twenty endophytic bacteria isolated from root nodules of Cicer arietinum and Vigna unguiculata were tested for their production of EPS. High EPS-producing isolates were identified on phenotypic and genotypic characteristics. Among 20 isolates, Stenotrophomonas maltophilia (C6) and Brevibacillus parabrevis (V4) isolated from root nodules of Cicer arietinum and Vigna unguiculata produced a high EPS yield in comparison with other isolates. Using 1% of sucrose as sole carbon source increases the concentration of EPS produced by S. maltophilia and B. parabrevis (65 and 107%, respectively). EPS produced by S. maltophilia and B. parabrevis was increased by the addition of fructose and lactose (0.1%). Addition of 1.68 g/L KNO3 or 2.49 g/L glycine to modified yeast extract mannitol medium (YEMB) significantly increased EPS production by S. maltophilia and B. parabrevis. Furthermore, the presence of Fe3O4 nanoparticles (25–50 μg/ mL) in the modified YEMB medium increased EPS yield by B. parabrevis. Chemical characterization of EPS by GC–MS and FTIR indicate that the EPS biochemical composition is dependent on the bioavailability of carbon substrates and is controlled by limiting nutrients. The combination of the best two carbon sources sucrose (0.9%) and fructose or lactose (0.1%) in the presence of KNO3 or glycine as the best nitrogen sources significantly increased EPS yield of S. maltophilia and B. parabrevis, respectively.

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This study was aimed to investigate the feasibility of bio- ethanol production by batch fermentation of kareish cheese whey. Two forms of whey; untreated (crude) whey containing 5% lactose and treated whey (deproteinized and concentrated to 14% lactose) were utilized. Fermentation processes were performed by two strains of Kluyveromyces marxianus and four strains of Saccharomyces cerevisiae which were previously recognized as ethanol- producing strains. Effects of different initial pH values, as well as, external supplementation of treated whey by four different nitrogen sources on the rate of ethanol production by two of the highest producing strains were also investigated. All the studied yeast strains were able to grow and produce ethanol from both crude and treated whey. Levels of ethanol production ranged between 3.4- 18.5g/l and 24.11-57.66 g/l from crude and treated whey, respectively. The most suitable initial pH maximizing ethanol yield was 5.5 and the best added nitrogen source was yeast extract. Maximum ethanol levels produced by K. marxianus ZMS3GU133329 and S.cerevisiae EC1118 from treated whey adjusted to pH 5.5 and supplemented by 0.3% yeast extract reached to 69.85 and 65.36 g/L, corresponding to 97.8 and 91.4% of the theoretical values, respectively. The kinetic parameters and productivity were calculated and discussed for all experiments.

Six high ethanol producer yeast strains (two strains of Kluyveromyces marixianus and four of Saccharomyces cerevisiae) were utilized to produce ethanol from treated and non-treated Egyptian sugar cane molasses with gravity (10, 15, 20, 30 & 33.3% sugar). The treated molasses was obtained by heating diluted molasses up to 90ºC and adjusting its pH to 4.5. All yeast strains used produced higher ethanol yield from non-treated molasses with 10% sugar than that obtained from the treated one with the same sugar concentration. On the other hand, treated molasses yielded better ethanol concentration than that gained from non-treated molasses with 15 – 25% sugar. Maximum ethanol production (125.89% g/l) was noticed with fermentation efficiency of 99.97% using S. cerevisiae EC1118 strain on 25% sugar treated molasses at 35ºC. The same strain gave low levels of ethanol when the sugar concentration of the treated molasses was either 30 or 33.3% at both fermentation temperatures used (35º and 40ºC). The kinetic parameters and productivity were calculated and discussed for all treatments.

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Alginate was recovered from Sargassum latifolium biomass using different conditions of alkali treatment.Box-Behnken experimental design was evaluated to study the influence of alkali:alga ratio, temperatureand time on alginate yield, and its molecular weight (MW) and mannuronic/guluronic acid ratio (M/G).The second-order polynomial equations were analyzed by appropriate statistical methods. Extractiontemperature and time were the most important factors during alginate alkaline extraction. MW andM/G ratio played an important role in controlling the reducing power of alginate. Increasing pH of thealginate solutions enhanced its reducing capacity, while thermal treatment showed a negative effect.Additionally, alginate exhibited good emulsion stabilizing capacities with diverse hydrophobic com-pounds. Emulsifying activity was less sensitive to temperature, ionic strength and more stable at acidicpH.