The present work is aimed to isolate, purify, identify a newly isolate Rhizobium fabae from different regions in Egypt then, produce and optimize Poly-β-Hydroxybutyrate polymer (PHB) production by the selected isolate Rhizobium fabae F44 using a statistical approach of response surface methodology (RSM). Rhizobium fabae F44 isolate was picked up from Sharkia Governorate in Egypt and then identified by the 16SrRNA gene as Rhizobium fabae. Eleven different variables which affect the production of PHB polymer were screened by Plackett–Burman statistical design approach. Maximization of PHB production was adjusted by the terms of The Face Central Composite Design (FCCD) of RSM and assessed at three coded levels (–1, 0, +1). One way Anova was used to statistically analyze all obtained results in relation to post hoc multiple comparison analysis performed by Tukey’s HSD. Appulses of nutritional and physical factors (two carbon sources, two nitrogen sources, mineral salts, pH, temperature, incubation time, inoculum size and agitation rate) were studied using Plackett-Burman design method. 58 isolates were obtained from the different 9 governorates with 100 % infection plant technique. The 16SrRNA showed a similarity of 99.56 (%) to Rhizobium fabae F44. Out of all tested significant media components, sucrose, yeast extract, agitation rate had the highest significant effects on the response as for PHB production, with confidence level > 98% and were further optimized using FCCD. Predicted Maximum PHB production was observed as (78.51%) which in near the mid-point (0) values (concentrations) of sucrose which reached (25 g/l) and yeast extract of (0.5 g/l) for 48 hrs. at 150 rpm agitation rate. The observed experimental value reached 87.5u/ml was very close result to the predicted one validating the model. So, Response Surface Methodology is an effective statistical approach which can substitute the use of one variable at a time approach due to its adequacy and efficiency to optimize PHB production by Rhizobium fabae F44.

In spite of the development observed in the area and production of potatoes crop in Yemen for the period of (1990-2010) to the level of self-sufficiency, the exported quantity, however, still very limited, It even decreased sharply in 2010 by 84.5%, compared to it's level exported in 2006. Stagnant productivity of potatoes in Yemen at around 13 ton only per-hectare, in front of (35- 45) ton/h globally, is believed to be the main obstacle standing behind the failure of exportation the Yemeni potatoes to the abroad. According to field study, several results have been obtained, the most important of which: The variables, such as, chemical fertilizer, equipment, manure and seeds are found to be the most effective factors on the output of potatoes. It is proved statistically significant at (0.01) level and responsible for the change occurred in the production of sampled individuals by 77% (R2), however, the result show that the quantity used in the production process of potatoes by mentioned above factors fill short to meat the level of optimal quantity required to maximize the profit.  The size of optimal level of production was estimated at (19.9) ton and the price of potatoes accepted by producers was estimated at 121390 YR/Ton. According to percentage of importance, seeds came first at the total variable cost by 31%, then, irrigation by 17.6%, fertilizers and pesticides 14.6%. Net revenue was estimated at (493640) YR, and the benefit /cost ratio was estimated at 1.40. The most important recommendation reached by this study is directed toward more using inputs in process of production by producers of potatoes, to maximize profit and increase productivity of area cultivated.

Among 20 bacterial isolates isolated from the soil of El-hawia, El-hada, El-kaym and Karwa in Taif governorate in Saudi Arabia,two isolates had high efficacy in producing cellulase enzyme. They belonged to genus Bacillus (Bacillus 8 and 17). Some factors such as carbon source and wheat bran as a raw material, nitrogen source, pH and. incubation temperature were investigated. Results indicated that CMC and cellulose were the most effective as they enhanced cellulases production .Sodium nitrate and ammonium chloride were the best nitrogen sources for cellulases production. Initial pH 7.0 was found to be optimal for growth and cellulase production. Incubation temperatures at 25 - 40°C achieved high cellulases production by the two isolates.

Among 17 fungal isolates isolated from soil of El-hawia, El-hada, El-kaym and Karwa in Taif governorate in Saudi Arabia, two isolates showed high efficacy in producing cellulases enzymes. They were identified to be Altemaria altemata and Aspergillus wentii. Some factors such as carbon and wheat bran as a raw material, nitrogen, pH and incubation temperature were investigated. Results indicated that glucose and cellulose were the most effective as a carbon source while, urea was the best nitrogen source for cellulases production. Initial pH 5.0 and incubation temperatures at 25 or 35°C achieved high cellulases production.

In order to produce neutral protease from Streptomyces microflavus, it was cultivated in basal medium containing soluble starch, potassium nitrate, dipotassium hydrogen phosphate, magnesium sulphate, sodium chloride, calcium carbonate and ferrous sulphate. Protease production increased with decreasing the ratio of culture broth to vessel volume 1:5 and shaking at 150 rpm. Protease production was low when pH was < 5 or > 9. The productivity of protease decreased sharply when the incubation temperature increased from 30 to 450C. The maximum yield of protease was obtained at the third day of incubation. Soluble starch and yeast extract were the best carbon and nitrogen sources, respectively. Supplementation with calcium carbonate enhanced protease production. In addition, the dipotassium hydrogen phosphate was the best phosphorous source. Para chloromercuribenzoic acid and phenyl methylsulfonylfloride had significant inhibitory effect on protease production.