Pseudomonas fluorescens is one of plant Growth Promoting Rhizobacteria (PGPR) members which has a major role in the biological control of bacterial and fungal pathogens. A research was conducted at the Laboratory of Microbiology, Faculty of Agriculture, Ain Shams University, Qalubyia governorate intended for isolating Pseudomonas fluorescens isolate, efficient in antibiotic production. For isolation, soil samples, collected from Faculty of agriculture farm soil at depth of 10 cm, were screened for Ps. fluorescens isolates by cultivating the samples on King’s medium. Out of 30 isolates obtained, one was selected based on its high lipid content, because of the lipid’s correlation to antibiotic production and inhibitory activity. The selected isolate was characterized by morphological, physiological, biochemical tests then confirmed its identity by 16S rRNA gene sequence analysis and named Pseudomonas fluorescens NBRC-14160 16srRNA. Morphological features showed that Ps. fluorescens NBRC-14160 has large colonies, with irregular surface, opaque, producing green fluorescent pigments. Cells are short rods, Gram negative. Physiological features indicated that Ps. fluorescens NBRC-14160 is capable of producing several exoenzymes including lipase, phospholipase, protease and chitinase and incapable of producing amylase and cellulase. Carbohydrate fermentation tests were positive for fructose, glucose, D-glucose, and galactose, forming acids after 24 hrs. of incubation at 30˚C. However, it loses the ability to ferment inositol, mannose, xylose, mannitol, raffinose and rhamnose sugars. It’s lipid content was 607 mg/g. Inhibitory activity was studied by the method of disc diffusion test against nine pathogenic bacterial and fungal strains. Staphylococcus aureus was the most sensitive bacterial pathogen towards P. fluorescens NBRC-14160 with a 4.5 cm zone of inhibition, while Serratia marscens had 0.95 cm zone. Aspergillus niger and Alternaria solani were the most sensitive fungal pathogens towards P. fluorescens NBRC-14160 with 2.55 and 2.5 cm of inhibition zone, respectively. However, the most resistant fungus was Fusarium oxysporum with 1.3 cm inhibition zone.

The aim of this study was to optimize the production of polyunsaturated fatty acids (PUFAs), using the response surface methodology (RSM), to use the produced PUFAs in kareish cheese processing. PlackettBurman design (PBD) was employed to screen media components that affect PUFAs development (glucose, olive cake, yeast extract, tryptone, MgSO4, KH2PO4, NH4Cl, agitation speed, incubation time, and pH), and results showed that olive cake and yeast extract, with confidence level > 98%, had a positive effect on PUFAs production. The central composite design (CCD) of the response surface methodology was used to optimize the selected parameters levels where maximum PUFAs production (1790 mg/l) was observed near the mid-point (0) values (concentrations) of olive cake (15 g/l), tryptone (7.5 g/L) and KH2PO4 (1.25 g/l). Polyunsaturated fatty acids account for 47.83 % of the total fatty acid profile, according to gas chromatography analysis of the collected PUFAs. The produced PUFAs was encapsulated using whey protein concentrate and maltodextrin, freeze dried, grinded and incorporated in Kareish cheese manufacture. The average particle size of a 0.005% suspension of oil microcapsules was 671.4 nm with a poly dispersity index of 0.611 indicating a moderate stability of the emulsion. The negative zeta potential of the microcapsules particles was -37.6 mv, which is identical to the -42 mv value recorded in the literature for oil emulsions stabilized by whey protein, maltodextrin, and K-carrageenan. The addition of 0.5 % PUFAs-containing microcapsules to Kareish cheese increased antioxidative activity to 38.13 % compared to 30.14 % for the control, as well as Texture profile analysis (TPA) parameters including hardness, cohesiveness, gumminess, and chewiness. The elasticity of the Kareish cheese sample increased slightly by the addition of 0.5% microcapsules, but higher concentration tended to change the elasticity to a brittleness of the cheese structure.

Accelerating global warming and water scarcity and improving water use efficiency are considered essential factors for achieving adequate crop development and productivity. Therefore, the authors targeted the use of arbuscular mycorrhizal fungi (AMF) and Pseudomonas fluorescens (Ps1) for improving growth, productivity, and water use efficiency of broccoli plants (Brassica olercea L. var. italica, cv. Belstar F1) under various irrigation regimes i.e., 50, 75, and 100% of crop evapotranspiration (ETc). Two greenhouse experiments were carried out in clayey soil. The combined inoculation of endomycorrhizae and Ps. fluorescens (Ps1) improved water use efficiency and consequently vegetative growth and yield. Under the applied irrigation regime 75% ETc of broccoli inoculated with both endomycorrhizae and Ps. fluorescens (Ps1) showed higher head weight (616 and 647 gram) than those grown under the irrigation regime 75% ETc combined with endomycorrhizae (568 and 559 gram) during the two seasons, respectively. However, a minimum yield value of 149 and 142 grams per plant was recorded for un-inoculated plants grown under 50% irrigation regime during both seasons. In conclusion, the combined inoculation with endomycorrhizae and Ps. fluorescens (Ps1) under irrigation regime 75% ETc was the optimum combination for increasing water stress resistance and broccoli productivity under water scar-city circumstances.