Plant biosurfactant-producing bacteria from crop rhizosphere soil and its effect on chickpea crop

Biosurfactants are surface-active molecules produced by microorganisms that can reduce surface and interfacial tension, offering numerous advantages over synthetic surfactants. This study aimed to isolate and characterize biosurfactant-producing bacteria and plant growth-promoting rhizobacteria (PGPR) characteristics from the rhizosphere soil of various crops and to evaluate their potential as a bio-inoculant for enhancing the growth and stress tolerance of chickpea (Cicer arietinum), a vital legume crop. Soil samples were collected from the college farm of PJTAU from the rhizosphere of red gram, maize, daincha, sunflower, and sesamum. A total of 40 bacterial isolates were initially selected based on morphological, cultural, and biochemical characteristics. These isolates were then screened for their ability to produce biosurfactants using various assays, including the oil spreading technique, emulsification measurement, surface tension measurement, drop collapsing test, and haemolytic activity. Plant growth-promoting rhizobacteria (PGPR) characteristics, such as phosphate solubilization, potassium solubilization, zinc solubilization, ammonium production, gibberellic acid, and IAA production, were also evaluated.