Characterization of phyllosphere methylotrophic bacteria isolated from the groundnut and their impact on growth, yield and quality of the kernel

Aim: The present study was undertaken to characterize and evaluate the habitat adopted methylotrophic bacteria on groundnut growth and yield at field level.Methodology: Nine elite methylotrophic bacterial isolates were selected based on early plant growth promotion and quantified for plant growth promoting (PGP) traits along with one standard strain, Methylobacterium thiocyanatum DSM 11490T. Two field experiments were carried out with eleven different treatments arranged in a randomized block design with three replications. Bacterial inoculant was applied as seed treatment as well as foliar application at 35 and 70 days after sowing. Plant growth and yield parameters were estimated periodically and after harvest. Results: All the tested isolates exhibited multiple PGP traits. In Vriddhachalam, the yield of groundnut was significantly higher in Methylobacterium thiocyanatum VRI7-A4 (1688.9 kg ha-1) followed by Paenibacillus hunanensis COG-4 (1675.8 kg ha-1) compared to un inoculated control treatment. In Tindivanam, yield content of groundnut was found significantly higher in Methylobacterium thiocyanatum VRI7-A4 (1678.6 kg ha-1) followed by Pseudomonas psychrotolerans K-TMV7-6 (1667.5 kg ha-1). In addition, Methylobacterium inoculation increased the kernel protein content as compared to the control treatment in both the field experiments. Interpretation: The results showed that Methylobacterium populi TMV7-4, Methylobacterium thiocyanatum VRI7-A4, Pseudomonas psychrotolerans K-TMV7-6 may be used as bio-inoculant for groundnut crop

Characterization and optimization of bacterial cellulose produced by Acetobacter spp.

im: The study aimed to search for a potential bacterial strain capable of producing maximal bacterial cellulose under optimized conditions for future scale up.Methodology: Eight cellulose producing bacterial strains were isolated from sugarcane juice using Hestrin and Schramm (HS) medium. These isolates were identified through 16S rDNA based on molecular phylogenetic approach and the cellulose mat was analyzed for their physico-chemical properties. Morphological, chemical and physical properties of cellulose mat was studied by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy spectrum, High Performance Liquid Chromotograpy and Differential Scanning Calorimetry. Optimal nutrient composition for maximum cellulose production by the isolate was carried out by response surface methodology.Results: 16S rDNA sequence analysis revealed that the isolates belonged to Acetobacter senegalensis, Acetobacter thailandicus, Acetobacter lambici, Acetobacter lovaniensis and Acinetobacter baumannii. Among them, A. senegalensis MA1 produced the maximum cellulose mat of dry weight 3.6 g per 500 ml of HS medium after 2 weeks of incubation. The morphology of bacterial cellulose produced by A. senegalensis MA1 had a pellicle shaped distinguished network structure and the rod shaped bacterium was attached to the bottom of cellulose mat. HPLC analysis revealed that the peaks obtained from bacterial cellulose were almost similar to carboxymethyl cellulose (CMC) peak. In cellulose mat, the weight of carbon, oxygen were 60.13 and 25.12, respectively. Analysis of differential scanning calorimetry showed endothermal peak at 139.8°C., indicating the melting point of bacterial cellulose mat. Through response surface methodology analysis, 5 g of glycerol and 1.2 g of yeast extract per 100 ml medium was optimized to get maximum cellulose production (2.04 g) from A. senegalensis MA1. Interpretation: Optimized condition for maximum bacterial cellulose production may be applied at industrial scale for commercial utilization