Application of chemical fertilizer is an integral practice to optimize crop productivity, but the dominant use of chemical fertilizers contributes largely to the deterioration of the environment, leads to loss of soil fertility, increases pollution, and causes hazardous diseases. Hence, the chemical fertilizers, pesticides and other supplements are being replaced by the plant growth promoting bacteria (PGPB) due to their improved potency and environment friendly nature. Plant growth-promoting bacteria (PGPB) can enhance plant growth by a wide variety of mechanisms like Phosphate (P) solubilization, Potassium solubilisation, siderophore production, biological nitrogen fixation and Indole acetic acid (IAA) production. The Klebsiella species is also known to exhibit important PGP traits like solubilization of phosphate, phytohormone production and good germination potential. In present study the Klebsiella pneumoniae PNE1 was selected from the isolates obtained from vegetable waste collected from Kadi market. The isolate was selected on the basis of its ability for Nitogen fixation, Phosphate solubilization, Potassium solubilization, IAA production, EPS production and biopolymer degradation. The molecular identification through 16S rRNA gene sequence, confirmed the isolate as Klebsiella pneumonia PNE1. Quantitative analysis of ammonia production revealed that isolate Klebsiella pneumonia PNE1 produced 0.5 µg/ml of ammonia (NH3) on 6th day of incubation and produced 0.09 µg/ml Nitrite after 8th day of incubation. The Phosphate solubilisation Index (SI) of the isolate was 4.16 and the isolate released 177.50 μg/ml Phosphate. The qualitative estimation of Potassium solubilisation by the isolate Klebsiella pneumoniae PNE1 in terms of Potassium solubilisation zone was found to increase gradually from day 1 to 7 days and was maximum at 2nd day with a KSI of 3.6. The isolate Klebsiella pneumoniae PNE1 released 29.94 mg/l Potassium on 21th day of incubation respectively. The IAA production was found to be 94.96 µg/ml. The maximum the EPS yield was 11.3 mg/ml. The Klebsiella pneumonia PNE1 had capacity to degrade Cellulose, Pectin and Xylan i.e. all biopolymers tested. The antibiotic susceptibility test indicated that isolate was sensitive to all 22 antibiotics tested. The Klebsiella pneumonia PNE1 thus, shows important plant growth promoting traits and can be used in a bio-fertilizer formulation for sustainable agriculture.

An extremely halotolerant bacterium designated as HPSSN35C was isolated from saline soil of Dwarka beach, India. It exhibited growth over a wide range of NaCl in medium varying from 0 to 6 M. The isolate produced peach-pink pigment above ∼1.3 M NaCl. The culture was characterized using biochemical tests, bioMerieux Staph identification kit, API ID32 Staph system, and Biolog. Due to slow growth and extreme salt tolerance no ID was obtained in Biolog. Antibiotic sensitivity to various antibiotics was tested. Phenotypic characterization showed that it belonged to the novobiocin resistant staphylococci group. Analysis of 16S rRNA gene sequence comparison of 1452 base pairs showed that isolate is closely related to Staphylococcus saprophyticus group with close relationship to Staphylococcus arlettae (99% similarity). The halotolerant S. arlettae described in literature till date have been reported to tolerate 4.5 M NaCl and produce white to yellow pigment. The present study reports for the first time extremely halotolerant S. arlettae exhibiting growth up to ∼6 M NaCl and producing peach-pink pigment above ∼1.3 M NaCl.

The exopolysaccharides (EPSs) are natural polymers of carbohydrates and are excreted by some bacteria outside of their cell walls. The microbial EPS have several biotechnological applications viz. cosmetics, textiles, pharmaceuticals, agriculture, paints and petroleum industries. The wide range of applications and bioactive roles of EPS has triggered increased interest for search unusual and novel EPS.The bacteria from marine ecosystem are also known to secrete novel EPSs. In this context, the main objective of this research is isolation, screening of most potent culturable EPS producing halotolerant bacteria with novel EPS characteristics which can be used in uncommon applications related to the environment. All the bacterial isolates were isolated from coastal regions of Gujarat as it contains 1600 km long costal area, with wide microbial diversity and can serve as a source for promising EPS producers. 9 soil samples were collected from various coastal sites viz. Mundra, Jodiya, Dwarka, Somnath, Diu, Bhavnagar, Khambhat, Dumas and Umargam. Total 59 EPS producing bacterial isolates were obtained in Primary Screening. Based on the results of primary screening, potential morphologically diverse 9 isolates were selected for EPS production in liquid medium. The EPS production ranged from 22.3 to 33.5 mg/ml. The isolate VHP 34 gave best EPS production and was identified as Enterobacter cloacae by 16 s rRNA gene sequencing method. The isolate Enterobacter cloacae VHP-34 was able to grow 0-15% NaCl concentration, hence categorized as Moderately Halotolerant.

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