EPS - Based Biofertilizer: An Eco-Friendly Approach to Improve Crop Productivity

Freshwater ecosystems support a wide range of cyanobacteria, which are photosynthetic
microorganisms known for their ability to produce extracellular polymeric substances (EPS). EPS is
a natural biopolymer that plays an important role in soil conditioning by improving aggregation, water
retention, and nutrient availability. Due to these properties, cyanobacterial. EPS has gained attention
as a sustainable alternative to chemical fertilizers.In the present study, water samples were collected
from freshwater sources and cyanobacteria were isolated using selective culture media. The obtained
isolates were purified through repeated sub-culturing and identified based on microscopic
morphological features, followed by molecular confirmation using 16S rRNA sequencing. To
maximize EPS production, key culture parameters such as temperature, pH, light intensity, and
nutrient availability were optimized under controlled laboratory conditions. EPS was extracted from
both extracellular (released) and cell-associated (bound) fractions u sing centrifugation, filtration,
ethanol precipitation, and dialysis purification. The purified EPS was quantified using the phenol–
sulfuric acid assay and characterized using analytical techniques including FTIR and NMR to confirm
functional groups and structural properties.Finally, the extracted EPS was formulated into liquid and
solid biofertilizer preparations and evaluated for its potential agricultural benefits. EPS-based
biofertilizers can enhance soil aggregation, improve nutrient retention, stimulate beneficial microbial
populations, promote root growth, and increase plant tolerance to drought and salinity stress. This
study highlights the promising potential of freshwater cyanobacteria-derived EPS as an eco-friendly,
cost-effective, and sustainable input for modern agriculture.