Basic methodology to isolate diazotroph from soil.

1. Diazotrophs: An alternative approach for chemical nitrogen to enhance
the biological nitrogen fixation in soil
Amit Kumar, Pooja Sharma, Anil Kumar Sharma
MMEC, Department of Biotechnology, Maharishi Markandeshwar (Deemed to be University)-Mullana (Haryana)
SUMMARY
Nitrogen is an essential element and a limiting factor for plant growth. In
atmosphere, nitrogen content is approximately 80% in the form of N2 whereas
plant access biological nitrogen for their growth in the form of ammonium and
nitrate only. Biological nitrogen fixation (BNF) is a natural process by which N2-
fixing bacteria (diazotrophs) convert atmospheric nitrogen into plant accessible
forms (ammonium and nitrate). Due to limitation of biological nitrogen there is a
huge demand of chemical nitrogen based fertilizer since 1980s globally. About 60
% of chemical nitrogen fertilizers are presently used for cereals. Both free-living
and associative N2 fixing bacteria are occurring in association with cereal crops,
sugarcane and other non-leguminous plants. The diversity of diazotrophic
communities was mostly based on cultivated members of the Proteobacteria,
green sulfur Bacteria, Cyanobacteria, and Firmicutes. Biological nitrogen fixation
by diazotrophic bacteria, reduces dinitrogen to ammonium using nitrogenase
enzyme systems, is one of the major phenomenons to enrich the nitrogen content
in soil and improves the agronomic conditions of soil fertility. It is reported that
non-symbiotic bacterial diazotrophs have major contribution in BNF system and
have potential to be a significant fixed nitrogen source in many terrestrial
ecosystems. Thus, their contribution to enhance the plant growth is one of the less
technically challenging ways to develop BNF in cereals and could reduce the
chemical nitrogen use in agriculture.
REFFERENCES:
• Bloch, S.E., Ryu, M.H., Ozaydin, B. and Broglie, R., 2020. Harnessing
atmospheric nitrogen for cereal crop production. Current Opinion in
Biotechnology, 62, pp.181-188.
• Roshani AK, Singh AV, Upadhayay VK, Prasad B. Development of
Potential Microbial Consortia and their Assessment on Wheat
(Triticum aestivum) Seed Germination. Environment and Ecology.
2020 Jan;38(1):6-16.
METHODOLOGY
• About one-third of the agricultural products are produced by
using pesticides and ultimately it harms the human health.
• So, it is a big challenge to replace the use of chemical fertilizer
by biological nitrogen.
• Diazotrophs, free-living bacteria are estimated to generate an
amount of fixed nitrogen equivalent to almost 60% of the
nitrogen produced industrially via Haber-Bosch. l
Diazotrophic
bacteria
stress tolerance
enhancement
solubilization and
Mineralization of organic
phosphate
improvement
of nutrient
uptake
inhibition of
plant ethylene
synthesis
Important of Diazotrophs
Diazotrophs and root associated bacterium that can fix and
supply nitrogen to cereals could offer a sustainable solution for
chemical nitrogen in a short period of time with lower
production costs and greater use efficiency.
CONCLUSION