Research Article Evaluation of Phytase Producing Bacteria for Their Plant Growth Promoting Activities Prashant Singh, 1 Vinod Kumar, 1,2 and Sanjeev Agrawal 1 1 Department of Biochemistry, College of Basic Sciences and Humanities, G. B. Pant University of Agriculture and Technology, Pantnagar 263145, India 2 Akal School of Biotechnology, Eternal University, Baru Sahib, Sirmaur 173101, India Correspondence should be addressed to Vinod Kumar; sangwan.vinod@yahoo.com Received 31 July 2013; Revised 5 November 2013; Accepted 6 November 2013; Published 23 January 2014 Academic Editor: Michael A. Cotta Copyright © 2014 Prashant Singh et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Bacterial inoculants are known to possess plant growth promoting abilities and have potential as liquid biofertilizer application. Four phytase producing bacterial isolates (phytase activity in the range of 0.076–0.174 U/mL), identiied as Advenella species (PB- 05, PB-06, and PB-10) and Cellulosimicrobium sp. PB-09, were analyzed for their plant growth promoting activities like siderophore production, IAA production, HCN production, ammonia production, phosphate solubilization, and antifungal activity. All isolates were positive for the above characteristics except for HCN production. he solubilization index for phosphorus on Pikovskaya agar plates was in the range of 2–4. Signiicant amount of IAA (7.19 to 35.03 g/mL) production and solubilized phosphate (189.53 to 746.84 g/mL) was noticed by these isolates at diferent time intervals. Besides that, a greenhouse study was also conducted with Indian mustard to evaluate the potential of these isolates to promote plant growth. Efect of seed bacterization on various plant growth parameters and P uptake by plant were used as indicators. he plant growth promoting ability of bacterial isolates in pot experiments was correlated to IAA production, phosphate solubilization, and other in vitro tests. On the basis of present indings, isolate PB-06 was most promising in plant growth promotion with multiple growth promoting characteristics. 1. Introduction It is well known that a considerable number of bacterial species, mostly those associated with the plant rhizosphere, are able to exert a beneicial efect upon plant growth. here- fore, their use as biofertilizers or control agents for agriculture improvement has been a focus of numerous researchers for a number of years. Bacterial inoculants have been used to increase plant yields in several countries, and commercial products are currently available. For example, in India, sev- eral biofertilizers are commercially produced and employed with diferent crops, mostly using strains of Azotobacter, Rhizobium, Azospirillum, and Burkholderia. Several possi- ble mechanisms have been proposed, including suppres- sion of diseases caused by plant pathogens [1], competition with pathogenic microorganisms by colonizing roots [2], production of plant-growth-regulating substances such as indole-3-acetic acid (IAA) [3], and lowering ethylene lev- els in root cells. Plant-stimulatory efects exerted by plant growth promoting bacteria (PGPB) might also be due to an enhanced availability of limited plant nutrients such as nitrogen, phosphorus, B-vitamins, and amino acids in the rhizosphere caused by phosphate-solubilizing and dia- zotrophic bacteria [4, 5]. Improved phosphorus nutrition is achievable by “mobilization” of phosphorus as insoluble inorganic polyphosphates and phytate, which accounts for 20–50% of the total soil organic phosphorus [6]. A number of PGPB are eicient in phytostimulation and biofertilization, and as biocontrol agents, but in most cases diiculties in obtaining successful formulations and insuicient knowledge of the basic molecular principles of their action has hindered their commercial use [7]. P is an important plant macronutrient, making up for about 0.2% of a plant’s dry weight. It is a component of key molecules such as nucleic acids, phospholipids, and ATP, and, consequently, plants cannot grow without a reliable supply of this nutrient. P is also involved in controlling key enzyme reactions and in the regulation of metabolic pathways. Ater Hindawi Publishing Corporation International Journal of Microbiology Volume 2014, Article ID 426483, 7 pages http://dx.doi.org/10.1155/2014/426483