*Author for Correspondence. E-mail: drsbmore@gmail.com INDIAN JOURNAL OF APPLIED MICROBIOLOGY Copyright © 2014 Indian Association of Applied Microbiologists, Chennai, India Volume 17 Number 2 July-December 2014, pp. 7-14. Phytase production by Bacillus species and Optimization of Fermentation parameters S.B. More*, Saiqua Khan, S.M. More, A.V. Girde and V.A. Shinde Department of Microbiology, Yeshwant Mahavidyalaya, Nanded- 431602 (M. S.), India. Abstract: Phytase production was studied by using two isolates of thermophilic Bacillus species S1 & S2 isolated from Yeshwant Mahavidyalaya ground soil sample. The Bacillus species S1 & S2 were screened for phytase activity using Sodium Phytate medium. The Bacillus species S1 & S2 failed to grow at 10°C and tolerated temperatures up to 50°C. The isolate S1 exhibited growth and caused phytase production at pH 8 and at 5% NaCl concentration, while S2 grown best at pH 9 and at 5% NaCl concentration. Phytase production (29.4 U/ml) and activity was found to be maximum by Bacillus species S1 on fourth day of fermentation. Observation of influence of temperature indicated the production of 22.5 U/ml at 40°C, then it reduced by every 10°C increase in temperature as the yield was 20 U/ml at 50°C and 18 U/ml at 60°C. Keywords: Phytase, Bacillus species, Thermophilic bacteria, Optimization. Introduction Phytase (EC 3.1.3.8) a specific group of phosphatases (1,2,3) that catalyse the de-esterification of phytic acid [myo-inositol hexakisphosphate] to myo-inositol and free ortho-phosphoric acid. The phytic acid and its salts, the phytates, contain the major part (up to 90 %) of the total phosphorus in the seeds of many plants (cereals, leguminous, oil producing) (4-8). This form of phosphorus however is not easily assimilated by monogastric animals such as swine, poultry, fish and human as they are not capable of metabolizing phytate phosphorus owing to the lack of digestive enzymes hydrolyzing the substrate and therefore inorganic phosphate is added to their diet to meet the phosphorus requirement. In addition, the undigested phytate phosphorus is excreted in manure