الفهرس 
1. INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The present study was conducted to optimize production of bioactive
compounds by Spirulina platensis, and estimation of its biological activities.
Cyanbacterium Spirulina platensis was grown in batch cultures containing
Zarrouk,s medium. Then compared with some physical (pH and UVB) and
chemicals, stresses as different concentrations of sodium nitrate, as a source
of nitrogen, dipotassium hydrogen phosphate, as a source of phosphorus,
potassium sulphate, as a source of sulfur, sodium chloride, as a source of
salinity and some heavy metals (zinc sulfate, as a source of zinc, copper
sulphate, as a source of cooper, and disodium selenate a source of selenium).
With the end of incubation time growth (as indicated by optical density) and
biomass production were estimated. Protein, carbohydrate, chlorophyll a,
carotenoids, flavonoieds and phenols was also estimated. Antibacterial
activities of Spirulina platensis, cultivated under physical and chemical
stresses were tested against different bacterial species (Pseudomonas
aeruginosa NCIB-9016, Escherich coliNCTC10418, Salmonella typhi,
Acinetobactersp, Klebsilla pneumonia) as gram-negative bacteria (Bacillus
subtilis NCTC-10400, Bacillus diminuta ATCC-19146, Staphylococcus
aureus, Staphylococcus aureus ATCC-25923) as gram-positive. The
obtained results indicated that the optimal conditions for production of
maximum growth as the following:-
1. The highest biomass production and optical density of Spirulina
platensis culture were found at the 21th day of incubation.
2. The maximum growth, protein, carbohydrates, chlorophyll a,
carotenoids, flavonoieds and phenols were attained at initial pH value
of 10.0.
3. In general, the exposure of the growing culture to UV light for
15mins. Slightly induced biomass, chl a, protein, carbohydrates,
except carotenoids at 30mins. the highest phenolic content was found
in acetone extracts at control and flavonoid content found in ethanol
extracts at UVB-45mins.
4. The optimum concentration of NaNO3 for the production of biomass,
protein, carbohydrates, and pigments chlorophyll a and carotenoids
was found to be 2.5g/l. The highest phenolic content was found in
acetone extracts at control and flavonoid content found in ethanol
extracts at the absent of nitrogen.
5. The concentration of NaCl present in the basal medium (1g/l), as a
positive control, was proven to be the optimum for the growth and
production of protein, carbohydrates, and pigments chlorophyll a and
carotenoids. The highest phenolic content was found in acetone
extracts at control and flavonoid content found in ethanol extracts at
concentration (4.0g/l) of NaCl.
6. The optimum concentration of K2SO4 for the production of biomass,
protein, carbohydrates, and pigments (chlorophyll a and carotenoids),
and the highest phenolic content was found in acetone extract was
found to be (1.0g/l) of K2SO4 except flavonoid found in ethanol
extract at absent of K2SO4.
7. The maximum growth, protein, carbohydrates, chlorophyll a, and
phenolic content at concentration of K2HPO4 (0.5g/l) except
carotenoids found to be (2g/) and flavonoid at (0.2g/).
8. The concentration of some heavy metals for the production of
biomass, protein, carbohydrates, and pigments (chlorophyll a and
carotenoids) was found to be (ZnSO4-1mg/l) and the highest phenolic
content was found in acetone extract at control and flavonoid found in
ethanol extract at concentration of Na2SeO3(1mg /l).
9. For determination the strongest solvents for production of the active
substance, the inhibition of Spirulina platensis were examined against
nine pathogenic bacterial. The tested bacteria were (Pseudomonas
aeruginosa NCIB-9016, Escherichia coli NCTC10418, Salmonella
typhi, Acinetobactersp, Klebsiella pneumonia) as gram-negative
bacteria (Bacillus subtilis NCTC-10400, Bacllius diminuta ATCC-
19146, Staphylococcus aureus NCTC-7447 ,Staphylococcus aureus
)as gram-positive bacteria .The results indicated that the strongest
solvent was 70% acetone followed by 70% methanol and finally the
effect shown by 70% ethanol.
10. The antibacterial activity of Spirulina platensis was determined
against bacteria and The optimal zone of inhibition of Spirulina
platensis extracts against bacteria was ranged between 15 mm to 20
mm as the following:
A. The 70% acetone extract of Spirulina platensis showed highest
zone of inhibition (20 mm) with Staphylococcus aureus,
Escherichia coli NCTC10418 at pH values 8.0.and
Staphylococcus aureus NCTC-7447 at pH values 8.0 and pH
values 10.0.
B. The 70% ethanol extract of Spirulina platensis showed
maximum antimicrobial activity of (20.0mm) against Bacillus
subtilis NCTC-10400 at of salinity 2g/l (NaCl) concentration.
C. Finally the70% methanol extract of Spirulina platensis showed
maximum antimicrobial activity of (20.0 mm) against
Staphylococcus aureus NCTC-7447 at pH values 8.0 and
(ZnSO4 - 1mg/l).