eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2024-07-01 21 2 411 423 10.13005/bbra/3235 51519 article Soniya Goyal 1 Amit Kumar 2 Pooja Sharma 3 Anita Rani Gill 2 Anil Kumar Sharma 2 Ashwanti Devi 1 Department of Biosciences and Technology, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala Guru Jambeshwar Science and Technical University, Hissar (Haryana), India. Amity University, Mohali, Punjab, India Nitrogen is an essential nutrient utilized by living organisms to produce a number of organic molecules such as nucleic acid, amino acid and protein. A special class of microorganisms known as diazotrophs that are able to fix atmospheric nitrogen into biological form of nitrogen which is directly utilized by plants. Moreover, they stimulate plant growth by decreasing or preventing deleterious effects of pathogens through synthesis of antibiotics, competition for nutrients through production of siderophores. Along with terrestrial diazotrophs, various marine bacterial species are well known which involves in biological nitrogen fixation process. In an open oligotrophic ocean, pelagic and sympagic nitrogen fixation has been shown a significant source of biological nitrogen for survival of oceanic living organisms. A different range of diazotroph have been reported at low temperature ice sea environment. The community of nitrogen fixing bacteria under deep anoxic bottom water is gradually increase. It may be possible that due to genetic variation population of nitrogen fixing bacteria increases under sea water. In this review article, authors have focused on nature of diazotrophs in terrestrial as well as in aquatic conditions. Moreover, the bacterial habitat and their classification, latest approaches and future prospects is also included in the manuscript. Thus, the study would be helpful for understanding the mode of action, their behavior and survival rate in different environment and beneficial for improvement in agricultural sustainability. https://www.biotech-asia.org/vol21no2/comparative-study-of-nitrogen-fixing-bacteria-in-terrestrial-and-aquatic-habitats-insights-and-future-prospects/ Biological Nitrogen Fixation Diazotroph Marine Symbiotic; Terrestrial; Pelagic