الفهرس 
Water
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Abstract
This work investigated the ability of some yeast species in removal of iron and manganese from ground water by biosorption mechanism.
Briefly, the results can be summarized in the following points:
1- Eleven S. cerevisiae yeast strains in alive and dead forms were screened for biosorption and bioaccumulation of iron ions from prepared aqueous solution.
2- S. cerevisiae F707 in alive form was found to be the highest for Fe+2 biosorption compared to other stains (21.9 mg Fe+2/gm yeast biomass).
3- All the tested S. cerevisiae strains in the dead form were less efficient for Fe+2 biosorbtion than alive form. The maximum Fe+2 biosorption efficiency (87.26%) was recorded by dead cells of S. cerevisiae F707. The minimum biosorption efficiency (13.98 %) was recorded by dead cells of S. cerevisiae FH820.
4- Screening of the selected Saccharomyces cerevisiae strains
for Fe+2 biosorption after 90 min revealed that five yeast strains in alive form were selected for Fe+2 biosorption study due to their high Fe+2 biosorption efficiency. S. cerevisiae F707 in the life form proved to be the most efficient for Fe+2 biosorption while the yeast strain FK907 gave the lowest Fe+2 biosorption value.
5- Study of the effect of different factors on Fe+2 biosorption and
residual gave the following results:Screening of F707 yeast strain for Fe+2 biosorption after different time intervals indicated that the highest removal efficiency for Fe+2 by yeast biomass was occurred after 20 min until 45 min.
- Results of the estimation of Fe+2 biosorption efficiency by F707 strain indicated that there was an increase in biosorption of Fe+2 with increasing the metal ions concentration in the culture filtrate of F707 strain. On contrary, biosiorption was decreased with increasing biomass concentration.
- Study of the effect of different pH values (4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5 and 9) on Fe+2 biosorption by F707 after 20 min indicated that the maximum Fe+2 biosorption by F707 was observed at pH 9 (5.37 mg/l) while the lowest Fe+2 biosorption value (4.80 mg/l) was observed at pH 5.5.
- Study of the effect of agitation rate on Fe+2 biosorption by S. cerevisae F707 after 20 min, indicated that the maximum Fe+2 biosorption was obtained at agitation rate of 150 rpm (5.24 mg/l) followed by agitation rate of 100 rpm (5.15 mg/l).
- Study of the effect of different temperatures on Fe+2 biosorption by F707 after 20 min indicated that the maximum Fe+2 biosorption value (5.35 mg/l) was obtained at a temperatures of 35 and 40ºC with Fe+2 residual value of 0.25 mg/l. The lowest Fe+2 biosorption value was 5.08 mg/l and obtained at a temperature of 25ºC with Fe+2 residual value of 0.25 mg/l.
6- Results of total sugars and proteins of S. cerevisae F707 in the presence and absence of Fe+2 show that in the presence of Fe+2 5.6 mg/l, the total sugars gave a value of 42.67 g100g-1 while total proteins was 44.10 g100g-1 while in the absence of Fe+2 (control), the sugars content was 48.78 g100g-1 and total proteins was 39.90 g100g-1.7- Energy dispersive x-ray (EDX) of S. cerevisiae F707 showed the appearance of a peak of Fe+2 in the treated cells compared to control cells.
8- Competition of Fe+2 with other heavy metals showed that Fe+2 in control sample without any other heavy metals added in the solution at 5.6 mg/l was 41.6 mg /g biomass, while the addition of other heavy metals could affected the percent of Fe+2 biosorption.
9- Effect of immobilized S. cerevisiae cells on sorption of heavy metals indicated the high adsorption affinity with efficiency alginate immobilized cells of S. cerevisiae F707.
10- Eleven S. cerevisiae yeast strains in alive and dead forms were screened for biosorption and bioaccumulation of manganese ions from prepared aqueous solution.
11- S. cerevisiae F25 in alive form was found to be the highest for Mn+2 biosorption compared to other stains (22.5 mg Mn+2/gm yeast biomass).
12- Resuls showed that all the tested S. cerevisiae yeast strains in the dead form were less efficient for Mn+2 biosorbtion than alive form.
The maximum Mn+2 biosorption efficiency (63.80%) was recorded by dead cells of S. cerevisiae F727 while the minimum biosorption efficiency (6.50 %) was recorded by dead cells of S. cerevisiae F707.
13- Screening of the selected Saccharomyces cerevisiae strains for Mn+2 biosorption after 90 min indicated that six yeast strains in alive form were selected for Mn+2 biosorption study due to their high Mn+2 biosorption effeciency. Data revealed that S. cerevisiae F125 proved to be the most efficient for Mn+2 biosorption and absorbed 21.98 mg Mn2+/gm biomass while the yeast strain F524 gave the lowest Mn+2 biosorption value.
14- Study of the effect of different factors on Mn+2 ⃘biosorption
and residual gave the following results:
- Screening of the selected Saccharomyces cerevisae strain for Mn+2 biosorption after different time intervals indicated that F25 gave the highest Mn+2 biosorption value at the first 30 min. until 45 min.
- Estimation of the biosorbed and residual Mn+2 using different Mn+2 and biomass concentrations in the culture filtrate of strain F25 indicated that there was an increase in biosorption of Mn+2 with increasing the metal ions concentration and a biosorption decrease with increase dose of biomass.
-The effect of different pH values (4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5 and 9) on Mn+2 biosorption by F25 after 30 min was investigated. Results indicated that the maximum Mn+2 biosorption by F25 was observed at pH 7 (4.38 mg/l) while the lowest Mn+2 biosorption value was 4.17 mg/l and observed at pH 4.5.
- The effect of agitation rate rate on Mn+2 biosorption by S.cerevisae F25 after 30 min was investigated, results indicated that the maximum Mn+2 biosorption (4.22 mg/l) was obtained at agitation rate of 150 rpm with the lowest Mn+2 residual value of 0.58 mg/l.
- Study on the effect of different temperatures on Mn+2 biosorption by F25 after 30 min indicated that the maximum Mn+2 biosorption value (4.08 mg/l) was obtained at a temperatures of 40 ºC with Mn+2 residual value of 0.72 mg/l while the lowest Mn+2 biosorption value was 3.57 mg/l and obtained at a temperatures of 20 ºC with Mn+2 residual value of 1.23 mg/l.
15-Results of estimation of total cellular sugars and proteins of S. cerevisae F25 in the presence and absence of Mn+2 indicated that in the presence of 4.8 mg/l Mn+2, the total sugars gave a value of 42.18 g100g-1 while total proteins content was 42.30 g100g-1. In the absence of Mn+2 (control) the sugar content was 51.36 g100g-1 while total proteins was 39.60 g100g-1.
16- Competition of Mn+2 with other heavy metals showed that Mn+2 in control sample without any other heavy metals added in the solution at 4.8 mg/l was 41.3 mg /g biomass, while the addition of other heavy metals could effected the percent of Mn+2 biosorption.
17- Energy dispersive x-ray (EDX) of S. cerevisiae F25 showed the appearance of a peak of Mn+2 in the treated cells compared to control cells.
18- Effect of immobilized S. cervisiae cells on sorption of heavy metals indicated the high adsorption affinity with efficiency alginate immobilized cells of S. cerevisae F25.