الفهرس 
Introduction & review of literatureOnly 14 pages are availabe for public view
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Abstract
Mushrooms existed on the earth even before man appeared on it, as evidenced from the fossil records of the lower cretaceous period. They have been most probably used by the pre-historic human as food, thus anthropologically speaking; there is possibility that man used the mushrooms as food when he was still a food gatherer and hunter on the chronology of cultural evolution (Wani et al., 2010).
Mushrooms have many unique properties that have played major roles in human history, religion, and culture (Hernandez et al., 2008). The Egyptians considered mushrooms as a delicacy and the Greeks believed that mushrooms provided strength for warriors in battle; the Romans regarded mushrooms as a gift from God and served them only on festive occasions, while the Chinese treasured them as a healthy food (Badr, 2005 and Jahan et al., 2010).
Mushrooms includes 14,000 to 22,000 species while the real number may be much higher associated with the un-description of species and the non-differentiation associated with overlapping morphological characters, there are 2000 species of mushrooms that are edible; however, a dozen of them are commercially cultivated; a few of them are highly poisonous if consumed (Samuel and Eugene, 2012 and Patel et al., 2012).
Mushroom structure
Mushroom is a soft delicate white fruit-body of the fleshy fungi. Real fungus is the microscopic fine thread-like body called mycelium, grows on the substratum or under the surface of the soil. At maturity, the mycelia come together in a very compact form and sprout and spread as umbrella like structure (Jahan et al., 2010).
Mushrooms have a club-shaped reproductive structure; the part of the organism that we see and call a mushroom is really just the fruiting body. Unseen is the mycelium-tiny thread that grows throughout the substrate and collects nutrients by breaking down the organic material. This is the main body of the mushroom; the mushroom doesnot contain chlorophyll and therefore it is known as eukaryotic heterotrophs which obtain food from decay in organic matter (Daba et al., 2008).
Mushroom body is composed of hyphae; mature hyphae forms fructifications most frequently protruding from the surface of the substratum. Mushroom fructifications are composed of two basic parts, the pileus and the stipe. The pileus can take various shapes, size and color, the flesh-filled fungal fructifications differ in color consistency depending on the species (Bernas et al., 2006). Figure (1) shows the fruit bodies of P. ostreatus. Some kinds of oyster mushroom contain colored fruit bodies, and one of which is yellow (Pleurotus cornucopiae) (ElBohi et al., 2005), pink (Pleurotus salmoneostramineus), white (Pleurotus florida) (Li et al., 2008), or dark-gray (Pleurotus ostreatus) (Kim et al., 2009).