The Effects of Low-cost Formulation of Biofertilizer Prepared from Pseudomonas Putida PT and Nutritional Supplements on Vegetative Characteristics of Basil.

Introduction: In recent years, the global demand for agricultural products has increased. One of the methods to increase crop yield, along with the decreased use of chemical fertilizers, is to apply biofertilizers. The purpose of the present study is to produce a lowcost formulation of biofertilizer synthesized from Pseudomonas putida PT. Materials and Methods: Various plant growth-promoting characteristics of P. putida PT such as P-solubilization, N- fixation, and Indole-3-acetic acid (IAA) production were assayed using Pikovskaya’s (PVK) medium, Salkowski reagent, and N-free medium, respectively. The effects of low-cost substrates to prepare inexpensive biofertilizers were analyzed by measuring the bacterial dry weight. The biofertilizer was prepared by the seed immersion method, and pot experiments were performed by using prepared biofertilizer from P. putida PT and nutritional supplements. The effect of various treatments on the growth and development of Ocimum basilicum (basil) was evaluated by measuring the root and shoot lengths, fresh weight of aerial parts, and dry weight of aerial parts. Results: P. putida PT exhibited capability of P-solubilization (OD430nm=1.1), IAA production (OD530nm=0.86), and N-fixation. The highest bacterial biomass was observed in the presence of cheese whey, followed by 2.5 °Bx molasses plus (NH4)2SO4. The prepared biofertilizer from this bacterium increased significantly plant growth, especially when it was used along with insoluble phosphate. The addition of biofertilizer and insoluble phosphate increased shoot length, fresh weight of aerial parts, and dry weight of aerial parts by 41.6%, 83.7%, and 25% compared to the untreated control plants, respectively. Discussion and Conclusion: The results of the study signify that P. putida PT can be used to prepare a cost-effective biofertilizer for the enhancement of plant growth. [ABSTRACT FROM AUTHOR]