Bioremediation of saline soil by cyanobacteria

Abstract

Cyanobacteria, of the domain bacteria, are one of the earliest monophyletic groups or molecular organs and are able to grow in all light-exposed habitats on the Earth. Cyanobacteria have developed mechanisms to adapt to a broad range of environmental factors during their long evolution. This chapter deals with cyanobacteria mechanisms in the soil nutrient cycle along with the phototrophic mechanisms that give them UV protection in various land-use patterns such as soil salinity stress and use of cyanobacteria in halophilic environments. Agricultural productivity is significantly increased by this cyanobacterial technology. The adverse effects of indiscriminate use of chemical fertilizers leads to diminished soil productivity and environmental quality. As a substitute for chemical fertilizer, cyanobacteria are economical, ecologically sustainable, and improve crop productivity and quality. The most preferable cyanobacterial biofertilizers are an effective consortium of Azollas spp. In an ecosystem, nitrogen fixation by free living cyanobacteria also significantly supplements soil nitrogen. Cyanobacterial species inoculate soil with a suspension of each species or a combination of species improving the germination percentage and influencing the other measured biochemical characters along with photosynthetic pigment segments of plants. This chapter also deals with phosphorus recycling by cyanobacteria, which is an important nutrient for saline soils and its crops. Consortium development in biofertilizers with cyanobacteria shows more potential, as it requires minimum dose and also increases nutrient transports in plants through bioaugmentation. Moreover, carbohydrates and proteins augmented with Na+ are triggered with UV-A, UV-B, and MAA. The combination of cyanobacterial cells with half the suggested quantity of the chemical fertilizer was usually more active than adding the full dose of the plant growth promoting chemicals.