الفهرس 
1. IntroductionOnly 14 pages are availabe for public view
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Abstract
The problem of industrial environmental pollution has become a threat to mankind and all living organisms and plants. The public become more interested and sensitive towards the protection of the environment and general awareness has now increased about the potential adverse effects of industrial effluents contaminated with various pollutants, including dyes, on the environment. The effluent from the dyeing industry is one of the most complex wastewater to be addressed because it contains toxic or carcinogenic, mutagenic compounds to humans and all living organisms. Several different methods have been found to remove these dyes from industrial waste, including physical, chemical, as well as biological treatment, which were highlighted in this study using some types of micro algae.
In this study; two stations were chosen as industrial polluted sites. Water samples were collected from suspected industrial sites in the part of Meat Bara drainage canal in Quisna, Menoufia Governorate, and from Sadat city in the industrial area.
Physico-chemical characteristics of untreated industrial wastewater
Water temperature: The recorded water temperature was (19.4oC) at station (1) in the part of Meat Bara drainage canal in Quisna and it was (20.6 oC) at station (2) in industrial region, Sadat city in May.
The pH value: the pH of water sample was slightly alkaline at both stations (2 and 1) and recorded (8.0 and 7.6), respectively.
Sulphate content: The maximum value of Sulphate content of water sample was recorded at station (2) (2.65 mg.l-1), and it was low value at station (1) (0.88 mg.l-1).
Nitrate content: The nitrate content of water sample was recorded high value at station (1) (0.72 mg.l-1 ) and at station (2) the nitrate content was (0.12 mg.l-1).
Ammonia content: The ammonia content of water sample was recorded high value at station (2) (0.25 mg.l-1) and it was recorded low value at station (1) (0.19 mg.l-1).
Phosphate content: The phosphate content of water sample at station (1) was (0.27 mg.l-1) and station (2) was (1.98 mg.l-1).
Silicate content: The silicate content of water sample was recorded high value at station (2) (0.89 mg.l-1 ) and at station (1) the silicate content was (0.76 mg.l-1).
Alkalinity: the alkalinity of water samples at station (1) was (14.4 mg.l-1) and it was recorded 15.9 mg.l-1 at station (2).
Chloride level: The chloride level of water samples was recorded high level at station (2) (98.3 mg.l-1) and it was (66.7 mg.l-1) at station (1).
In this investigation, four algae species were isolated from the previous pollutant industrial regions, then purified and identified as: Chlorella vulgaris, Aphanocapsa elachista, Pseudoanabaena sp. and Microcystis aeruginosa. These species were used in degradation studies of the dyes and azo dyes.
Dyes used in this study
Four dyes were kindly supplied from Dyeing Factory at the industrial region district Quisna, Menoufia Governorate which used in the present study.
The used dyes were (Disp Red BS and Reactive black NN) and azo dyes (Reactive yellow 3RN and Disp Orange 2RL).
The results are summarized as follows:
Degradation of different dyes by microalgae: Algae can degrade a number of dyes and azo dyes to some extent. The reduction rate appears to be related to the molecular structure of the dyes and the species of algae used.
Degradation of Disp.orange 2RL azo dye by different microalgae
The obtained results recorded that Microcystis aeruginosa has the high degradation percentage (65.07 %), followed by Chlorella vulgaris (55.22%) and then Pseudoanabaena sp. (42.98 %) and the least degradation percentage represented by Aphanocapsa elachista (20.59 %) after 7 days of incubation .
Degradation of Tracid red Bs dye by different microalgae
The results in this study showed that Pseudoanabaena sp. has the high percentage of degradation (78.44 %), followed by Microcystis aeruginosa (50.01 %) and then Aphanocapsa elachista (48.27 %) and the least degradation percentage represented by Chlorella vulgaris (35.34 %) after 7 days.
Degradation of Reactive Black NN dye by different microalgae
The obtained results showed that Microcystis aeruginosa has the highest degradation percentage (55.12 %), followed by Pseudo anabaena sp. (36.24 %) and then Aphanocapsa elachista (31.5 %) and the least degradation percentage represented by Chlorella vulgaris (9.32%) after 7 days.
Degradation of Reactive Yellow 3RN azo dye by different microalgae
The present results showed that Pseudoanabaena sp. has the highest degradation percentage (58.47 %), followed by Microcystis aeruginosa (52.47 %) and then Aphanocapsa elachista (49.16 %) and the least degradation percentage represented by Chlorella vulgaris (31.53%) after 7 days.
Dry weight estimation
The obtained results showed that different dyes and azo dyes significantly decreased the dry weight content of different algae as compared with the control. However there is a gradual increase in growth by increasing incubation time and this is accompanying with the increase of percentage of degradation
Protein estimation
The obtained results demonstrated that the protein content was increased with respect to incubation period as compared with the control
The protein content of Pseudoanabaena sp. showed the highest content after 7 days with Disp.Red BS, while the protein content of Microcystis aeruginosa showed the highest content after 7 days with Disp.orange2RL
Also the results recorded high protein content of Aphanocapsa elachista after treatment with Disp.Red BS, and the protein content of chlorella vulgaris showed high accumulation on 7 days with Disp.orange 2RL. These results of protein content confirmed the results of degradation
Infrared Spectrum determination of the biomass of algae and the dyes
The obtained results showed that there were differences in the IR peak of the biomass of algae before and after treatment with dye and showed that some peaks are shifted or disappeared and some new peaks emerged after dye absorption.
In the present results the obtained differences in spectral intensity and the occurrence of stretched vibration at 1516 cm-1 and 1600 cm-1 for N=N- azo bond for some IR figures of biomass of some algae treated with some dyes also evident possible biosorption besides the algal degradation activities. These results suggest the ability of these algae to induce azo reductase enzyme under azo dye stress to cleavage of azo linkage and the formation of aromatic amine.
Such difference in IR intensity confirms the results of degradation of this dye.
Estimation of azo dye reductase enzyme of Chlorella vulgaris, Pseudoanabaena sp., Microcystis aeruginosa and Aphanocapsa elachista
The azo reductase enzyme of Chlorella vulgaris after treatment with Disp.orange 2RL induced azo dye enzyme activity after 3,5 and 7 days of
incubation by about 56.82 %, 60.73 % and 62.17 %, respectively, as compared with the control.
Also, the addition of Disp.orange 2RL induced the azo reductase enzyme activity in Microcystis aeruginosa by about 66.29 %, 67.96 % and 68.04 %, respectively, after 3, 5 and 7 days.
It is obvious that the addition of Reactive yellow 3RN induced azo reductase enzyme of Pseudoanabaena sp. after 3, 5 and 7 days of incubation, by about 50.26 %, 53.07 % and 55.64 %, respectively, and the azo reductase enzyme of Aphanocapsa elachista after treatment with the same azo dye induce the Azo reductase enzyme activity by 47.06%,52.23 % and 52.48 % , respectively.
These findings suggest that azo reductase in Chlorella vulgaris, Pseudoanabaena sp., Microcystis aeruginosa and Aphanocapsa elachista is an induced enzyme and the substrate itself can act as an inducer. The induction causes a marked enhancement of the enzyme activity.
Gas chromatogram analysis of Chlorella vulgaris before and after treatment by Disp.Orange 2RL
In the present investigation GC-MS was used to analysis the products of degradation of Disp.orange 2RL dye before and after treatment by Chlorella vulgaris after 7 days of incubation. There are some major peaks which appeared before the biodegradation process at retention time 9.21, 23.51, 50.58, 54.95 and 55.61 min, and after Chlorella vulgaris biodegradation action these peaks were disappeared and new peaks were appeared at retention time 6.55, 10.65, 13.24, 22.70 and 49.79 min.
The mass spectrum of fragmentation of the parent dye yield nine intermediate compounds which were identified as N- methyl-1- adamantane acetamide , Tris (Tert - butyldimethylsilyoxy) arsane , 1 - ALLY 1-2,3- dimethoxy - 4,5 - methylene dioxybenzene or Dillapiole , 2-cyclohexen-1-one,2- methyl-5-(1-methylethenyl), D-Carvone, 6- Aza-5,7,12,14 - Tetrathiapentacene ,Cyclotetra siloxane,decamethyl , 2,5-Dihydroxyacetophenone,bis(trimethylsilyl)ether,and Cyclotetrasiloxane,octamethyl.
Based on the enzymatic studies and GC-MS analysis, the current results showed that azo bond in Disp.orange 2RL dye was cleaved by azo reductase enzyme during the biodegradation process leading to damage in the primary chromophore.