الفهرس 
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Abstract
Covering over 70% of the Earth’s surface, marine ecosystem is the home for a wide variety of animal and plant species whose number greatly exceeds that of terrestrial ones. Amongst those biodiversity, microbial world represents a potential research object to be explored as the recent investigations on marine bacteria have given the impact to the entire world as a source of bioactive metabolites producers. The area of application of biologically active compounds from bacterial origin is wide, involving agricultural, industrial, and pharmaceutical sectors. The secondary metabolites from marine bacteria, especially those with unique color pigments, not only play an important role in bacterial life, but also have diverse biological properties such as antibiotic and anticancer activities.
In last few decades, there has been an increasing trend towards replacement of synthetic colorants with natural pigments because of the strong consumer demand for more natural products. Natural pigments and synthetic dyes have been extensively used in various fields of everyday life such as food production, textile industries, paper production, agricultural practices and researches, water science and technology. Interest in use of natural colorants is increasing worldwide. Different from artificial synthetic colors, they are much more reliable due to their excellent stability. In addition, they can be mixed in numerous ways due to their various color tones. Natural food colors are more desirable than artificial dyes for both nutritional and marketing reasons.
On the other hand, synthetic pigments cause considerably environmental pollution and adverse toxicological side effects. The effluents released from the dyeing units of these industries contain synthetic dyes that are toxic and cause extensive environmental pollution besides polluting the ground water resources of drinking water and agriculture practices. Consequently, synthetic dyes have a significant negative impact on the environment. Moreover Synthetic colors are responsible for the hypersensitivity reaction in humans.
Although there are a number of natural pigments, only a few are available in sufficient quantities to be useful for industry because they are usually extracted from plants. In spite of the availability of variety of pigments from fruits and vegetables, there is an ever growing interest in microbial pigments due to several reasons like their natural character and safety to use, production being independent of seasons and geographical conditions, controllable and predictable yield. The rapid growth of microbes reduces the production time to a matter of days. Compared to plant or animal sources, the production is flexible and can easily be controlled. Therefore, there is an increasing interest involving microorganisms as a possible source of alternative colorants that are natural, cost effective and easily degradable and without production of recalcitrant intermediates when they enter the ecosystem.
This research aims to link between the science with promising applications in several fields of scientific research and marine microbiology to achieve a safe and friendly environment for the production of such pigments. The research also includes the application of these interesting pigments. This research is authentic in its content.
The aim of the present work is concentrated on the production of some microbial interesting pigments. In order to realize the aim mentioned above, this work focuses on the following main tasks:
1. Isolation and screening of pigment producing marine microbes.
2. characterization and identification of the most promising organism.
3. Study the effect of growth parameters on pigment production.
4. characterization of the microbially produced pigments.
5. Optimization of pigment production.
6. Evaluating the pigment produced in some applications.
The expected return
The successful isolation of natural pigments from marine bacteria will open a new avenue for replacing the synthetic pigments currently used in food, pharmaceutical and medical fields by more safe biological pigments. There is a big chance that these pigments might possess antimicrobial or anticancer activities, thus contributing to the benefit.