DEVELOPMENT OF PGPR BASED LIQUID INOCULANTS USING DIFFERENT WASTE PRODUCTS
Loading...
Date
2021
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
DRPCAU, PUSA
Abstract
In the present study, 32 PGPR based liquid inoculants were prepared using different combinations of carrier (nutrient broth, water + Oil), emulsifier (Tween-80/Triton-X-100), thickeners (carboxy methyl cellulose, corn cob powder and sugarcane bagasse), pH maintainer (eggshell powder) and protective agents (polyvinylpyrolidine, glycerol and gum arabic) among those 24 were nutrient broth based and 8 were water based liquid inoculants. PGPR consortium was added into these formulations, which was prepared with six bacterial cultures viz., Bacillus sp. (BS5), Pseudomonas sp. (PS2, PS3), Azotobacter sp. (AZT1, AZT2) and Azospirillum sp. (AZS3) after finding that they were compatible with each other. Further the individual bacterial cultures and the developed PGPR consortium were screened for plant growth promoting characters viz., phosphorus solubilization, Zn solubilization, siderophore production and IAA production. It was found that plant growth promoting characteristics of PGPR consortium (PSI-3.9cm, ZnSI-3.54cm, IAA-163 μg mg1 protein and siderophore production efficiency- 257%) was higher than the individual cultures. The developed liquid inoculants were stored at three different temperatures such as 4°C, 28°C and 40°C. They were characterized for shelf life (cell count), suspensibility and pH at 1month interval up to 8months. After 8months of storage, the formulation stored at stored at 4°C showed highest cell count,stable pH and low
suspensibility followed by formulations stored at 28°C and 40°C in both nutrient both based and water based formulations.When compared to the water based formulations, nutrient broth based formulations showed more fluctuations in pH and cell count.But in terms of survivability nutrient broth based formulations showed highest cell count as compared to water based formulations after 8months of storage period.Among the nutrient broth based formulations, those formulation where 75% nutrient brothwas used, showed highest shelf life and pH followed by 100% (NB) and 50% (NB). Shelf life was highest in the formulations prepared with all types of thickeners (CMC + CP + SB) followed by formulations with two types of thickeners and single thickener at all storage temperatures. Formulation F16 (NB-75% + T-80/T-100 + GA+ PVP + GLY+ EP + CMC+ SB + CP) showed highest cell count i.e., 63 x108 cells/ml, 59 x108 cells/ml and 56 x108 cells/mlat 4°C, 28°C and 40°C respectively. Whereas in case of water-based formulations, formulation F32 (Water + Oil + T-80/T-100 + GA + PVP + GLY + EP + CMC + SB + CP) showed highest cell population. Least cell population was observed in those formulations (F1, F9, F17 and F25) which were prepared without any thickeners. The formulations have been checked and found to possess a shelf life of 8months and this new PGPR based liquid formulations using waste products can play significant role in sustainable utilization waste management and help in restoring the soil health and productivity on long term basis with its availability and applicability.