الفهرس 
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Abstract
The objective of this study investigated of biomass from aquatic environments, such as seaweeds (macroalgae). Biomasses for the production of bioethanol could be divided in three generations according to the sources of sugar, The FGBs refer to biofuels made from sugar, starch, vegetable oils, or animal fats using conventional technology. SGBs and TGBs are also called advanced biofuels. SGBs are made from nonfood crops as; wheat straw, corn, wood, and energy crops using advanced technology. Algae fuel, also called algal oil or TGB, is a biofuel from algae. Bioethanol produced in three steps: pretreatment, saccharification, fermentation. Biomass for the production of bioethanol pretreated using two methods of thermal acid hydrolysis (chemical treatment) dilute acid and concentrated acid, effective pretreatments of seaweed for bioethanol production because they could degrade polysaccharides to fermentable sugars. Seaweeds had been studied as an alternative source of starch and lignocellulosic biomass for the production of bioethanol. The use of seaweeds did not present as food, feedstock and lignin-free with a carbohydrate composition of >50%.
The main experimental results could be summarized in the following points: Marine algae from Port Said coast El fyrouz site was collected in April 2013, were observed the results of temperature, salinity, PH and dissolved oxygen were 22.35oC, 30.91±2 %, 8.05-8.12 and 6.14-6.72 mg.l-1, respectively. Different fresh masses; 540, 399 and 495 g were collected for Ulva lactuca, Ulva fasciata and Enteromorpha intestinalis, respectively. Biomass percent for Ulva lactuca, Ulva fasciata and Enteromorpha were 70, 73.96 and 70.2 g, respectively.
The biochemical composition of Ulva lactuca, Ulva fasciata and Enteromorpha intestinalis included moisture content, ash, organic material, polysaccharides, LMWC and carbohydrate from the studied species. The ash content of Ulva fasciata and Enteromorpha intestinalis were lower value than the value of Ulva lactuca, which determined 18.15 % of dry cell weight. In addition, organic material contents showed the higher percent of dry cell weight of Ulva fasciata than Ulva lactuca and Enteromorpha intestinalis, which determined 85.13 % of dry cell weight. Carbohydrates` contents and total amounts of Low-molecular-weight carbohydrate (LMWC) were 55.42-57.60 and 2.56-3.08 % of dry cell weight, respectively. The maximum content of polysaccharide was 54.41 % of dry cell weight reported for Ulva fasciata.
Total content of cellulose and hemicellulose was analyzed by the method of two-step acid hydrolysis. The maximum reducing sugars content was 45.69 mg.ml-1 of Ulva fasciata and also the minimum reducing sugars content was 39.60 mg.ml-1 of Ulva lactuca. In this method the first step for treatment with high concentrated acid that degradation a part of monosaccharides in hydrolyzate which analyzed and the cost increasing with increasing acid concentration.
There were two types of acid hydrolysis; one of them diluted acid and another used concentrated acid. Both of them are required in algal biomass treatment, because each type of acid hydrolysis produced a type of reducing sugar (pentoses and hexoses). The first optimal treatment was obtained at 0.4M sulphuric acid in 121oC autoclaved for 60min. The maximum amount of reducing sugar were 21.02±0.085, 20.98±0.093 and 23.13±0.060 mg.ml-1 Enteromorpha intestinalis, Ulva lactuca and Ulva fasciata, respectively.
The second optimal treatment was obtained at 20 min at 50oC with 8.5M of sulphuric acid treatment. The maximum amounts of the saccharification hydrolyzed sugars from Enteromorpha intestinalis, Ulva lactuca and Ulva fasciata were 27.22±0.09 mg.ml-1, 25.4±0.046 mg.ml-1 and 27.3±0.036 mg.ml-1, respectively.
Direct neutralization was found to be somewhat effective in removing sulfate anions. Therefore, the saccharification solution which was produced from algal biomass with sulphuric acid treatment was optimized pH to reach 5.6, which suitable for yeast growth and to force the fermentation process.
Bioethanol was produced by microbial fermentation of sugars. The yeast Saccharomyces cerevisiae was the standard for sugar fermentation to ethanol. In this study two strain of Saccharomyces cerevisiae, Saccharomyces cerevisiae commercial strain and Saccharomyces cerevisiae SK.NY strain were used for comparing the results of strains and the amount of produced ethanol, which produced from fermentation of monosaccharides of the hydrolyzed solution by two yeast strains. The results of two yeast strains, which observed that S. cerevisiae SK.NY strain was the best ethanol producer in this study research. The saccharification of hydrolyzed total sugars (mixture of glucose - xylose sugars) from Ulva lactuca, Ulva fasciata and Enteromorpha intestinalis were 46.38±0.14 mg.ml-1 represented 43.14 % of total carbohydrates, 52.31±0.11 mg.ml-1 represented 47.13 % of total carbohydrates and 49.53±0.11 mg.ml-1 represented 45.63 % of total carbohydrates, respectively. The fermentation process of glucose-xylose sugars were successfully fermented and the productivity of ethanol was raised from 11.52 to 16.94±0.15 mg.ml-1, 13.41±0.53 to 20.39±0.34 mg.ml-1 and 12.75±0.37 to 19.74±0.13 mg.ml-1after 72 hours, respectively. This related to SK.NY was recombinant xylose-fermentable strains, therefore were more able utilize all reducing sugars (glucose-xylose sugars) and produced ethanol.