Acknowledgment: I thank God for all the blessings. I would like to express my kindest regards and gratefulness to my supervisor Dr. Hassan Mahmoud Gebreel, Assistant Professor of Microbiology, Ain shams University and Dr. Khaled Zakaria El-Baghdady, Lecturer of Microbiology, Ain shams University for their valuable guidance, direct supervision and their valuable revision. My deep gratitude and sincere thanks to Prof. Dr. Hussein Abd-Kareem Ahmed, Professor of Microbiology, NCCRT institute for his effort in constructive criticism and valuable critical reading and revision the manuscript. Sincere especial thanks are to prof.Dr. Nahed Abdel Ghaffar Abdel Aziz Ibrahim Head of Microbial Molecular Biology Department, AGRI institute , great encouragement, her effort throughout the Ph.D, valuable scientific ideas and advices. Also, for her inspiring guidance. I wish to thank Prof. Dr. Karl Forchhammer at Tubingen University for his unlimited support, valuable advice, sending some important chemicals used in this work. I also, like to thank him giving the chance to learn with right way. Finally, my great respect and gratitude to every one who participated in completion of this work.