الفهرس 
1. INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 108 |  |  |
| | | from | 108 | | |
Abstract
Marine environments, in particular those presenting extreme conditions , remain largely unstudied and unexploited. The marine environment represents an enormous pool of potential microbial biodiversity, ranging from Gram-negative bacteria , Gram-positive bacteria , archaea , yeast and fungi , collectively all these organisms revolutionized the cold marine biotechnology. Psychrotrophs are found in the same cold environments as psychrophiles but in greater numbers suggesting that psychrophiles evolved from the psychrotrophs.
The data obtained in this work are summarized in the following points.
1. from July 2008 to June 2009, water and sediment samples were collected from different stations along Mediterranean sea shore and analyzed for physical and chemical properties.
• Temperature readings ranged between 23.7 oC sediment and 24.5oC water during the study period.
• pH values showed tendency toward alkalinity ( 7 to 8.3).
• Salinity values ranged between 35.7 and 38.1 ‰. Organic matter of water sample ranged between 30.2 and 70.2 mgl-1.
• Dissolved oxygen (DO) levels ranged between 3- 6.9 mg /l.
• All nitrogen forms showed high level in water. In that respect, ammonia (NH4) recorded 6 - 45.2µg at. NH3_N. Similarly, nitrate (NO3) ranges were 12.6-44.5µg at. NO3_N. while nitrite (N O2) ranges recorded 0.42 - 17.9µg at. N O2_N.
• Similar behavior was shown by phosphate (PO4) recording (15.5 -31.7 µg/l and 9.7 - 24.6µg/l) in water and sediments respectively.
2. A variety of growth media were used to count and isolate cold adapted bacteria from water and sediment samples from different study areas. Aerobic heterotrophs were counted on sea water agar and ranged between 15x106 (CFU/ ml) in Rashid and (62x107 CFU/gm) in the Eastern Harbour and El-Agami sediments.
3. A total of 23 isolates were selected based their capability to grow at 5°C and showing different morphological morphotypes. The purified isolates were identified by amplification and sequenaing the 16S rDNA. Sequence analysis lead to the identification of 14 isolates as member of genus pseudomonas , 3 isolates as Psychrobacter species , two (Gram+ve) Planomicrobium sp. and one strain of Pseudoalteromonas , Halomonas , Paracoccus and Stenotrophomonas . They were all able to grow at 5-30 °C indicating their psychrotrophic character.
4. The selected 23 isolates were further characterized with respect to their cell morphology , Gram staining , growth condition and other phenotypic traits , antibiotic (Amikacin , 30µg, Ceftazidime, 30µg , Cefoperazone ,75µg Ampicillin, 20µg Ampicillin , 10µg Amipenem , 10µg Rifampicin , 5µg Doxycycline , 30µg Ceftriaxone , 30µg and Subphamethoxazole , 25µg).
5. Growth curves at different temperatures (5-30°C) were determined in liquid cultures. Data revealed that almost all grow best at 20-30°C , but slower growth was recoreded at 10 °C. Almost all strains showed high metabolic degradative ability being able to degrade starch, gelatin, chitin, tween20 & 80, skim milk and cellulose.
6. The ability of the isolates to interact with different heavy metals were studied. The Minimum inhibitory concentrations of Pseudomonas species ranged 500-400 (ppm) for Zn2+,150-400 (ppm) for Ni2+, 150-400 (ppm) for Cu2+, 150-400 (ppm) for Cd2+ and 750-800 (ppm) for Pb2+. Psychrobacter group showed different pattern, The Minimum inhibitory concentrations for Zn2+ ranged for 50-300 ppm , 300-400 ppm for Ni2+, 150-300 ppm for Cu2+, 25- 400 ppm for Cd2+ and 800 for Pb2+. Planomicrobium group ranged for 250 ppm for Cu2+ to 700 ppm for Pb2+. With respect to bioaccumulation results Lead is more reliable metal to be bioaccumulated than cupper and cadmium. Pseudomonas sp.H69A and Pseudomonas sp.H67 bioaccumulated all metals (lead, cupper and cadmium) efficiently. With respect to lead, the bioaccumulation value ranged from 0.283 to 2.950ppm, Psychrobacter sp.H41A is the most potent species in bioaccumulation of the different metals. It accumulated 2.720, 1.702 and 1.850 ppm of lead, cupper and cadmium respectively and Planomicrobium sp.H44A bioaccumulated lead and cadmium more efficiently than Planomicrobium sp.H71 , it bioaccumulated 0.906 and 0.843ppm respectively.
7. The work was extended to study effect of Pb2+ conc. On Pb2+ bioaccumulation by Pseudomonas sp.H69A, also effect of time contact and effect of different temperatures and the results showed that, the highest level of bioaccumulation was 92% detected after 60 min. at 30 oC.
By applying Plackett-Burman design, for maximum bioaccumulation of lead by Psychrobacter sp.H41 and the predicted medium had the following formula (g/l): tryptone , 7; glucose, 1.5; K2HPO4 , 0.3; yeast extract , 1.5 and MgSO4 , 0.25; inoculum size , 1.5 ml and seawater volume must be 750 ml.
8.With respect to azodyes bioremediation, the results showed that, maximum decolorization activity was recorded in fast orange by strains of Pseudomonas.
Eight strains of Pseudomonas species were able to biosorp more than 50% of fast orange.
For Pseudmonas sp.H26S and Pseudomonas sp.H45A , the detected biosorption percentages were (91% and 85% respectively) with biosorption capacities 4.1mg/g , 4.8mg/g.