Biosynthesis of Zinc Oxide Nanoparticles using Plant Growth promoting Rhizobacteria of Curcuma longa and Zingiber officinale

The biosynthesis of zinc oxide nanoparticles (ZnO NPs) using plant growth-promoting rhizobacteria (PGPR) offers an environmentally acceptable and sustainable alternative to traditional chemical and physical synthesis methods. This work explores the production of ZnO NPs using PGPR isolated from the rhizosphere soil of two medicinal plants Curcuma longa (turmeric) and Zingiber officinale (ginger). The isolated PGPR were characterised by their plant growth-promoting features, including phosphate solubilization, cellulose degradation, zinc solubilization, indole acetic acid (IAA) synthesis and siderophore secretion. Additionally, the screened isolates were tested at various salt concentrations, ranging from 0.5% to 7.5%, to assess their salt stress tolerance. The biosynthesis of ZnO nanoparticles using bacterial isolates was validated by visual monitoring of turbidity changes in reaction mixes containing zinc salts. The formation of turbidity suggested nanoparticle production. The present study demonstrates the successful production of zinc oxide nanoparticles (ZnO NPs) using plant growth-promoting rhizobacteria (PGPR) from Curcuma longa and Zingiber officinale.