Study of Physicochemical factors on dipicolinic acid formation by Bacillus cereus PTCC1015

Subject Areas : Bacteriology

Saber Niksirat ¹ , Mohammad Faezi Ghasemi ² , Khosro Isasazadh ³ , Mohammad Reza Khosh Kholgh Pahlaviani ⁴

1 - Department of Microbiology, Lahijan Branch, Islamic Azad University, Lahijan, Iran
2 - Department of Microbiology, Lahijan Branch, Islamic Azad University, Lahijan, Iran
3 - Department of Microbiology, Lahijan Branch, Islamic Azad University, Lahijan, Iran
4 - Department of Microbiology, Lahijan Branch, Islamic Azad University, Lahijan, Iran

Received: 2013-06-21 Accepted : 2013-06-21 Published : 2012-01-01

Keywords: Bacillus cereus, DPA, colorimetric, Spore,

Abstract :

Background and Objective: Dipicolinic acid (pyridne 2, 6 dicarboxylic acid) is a major component of bacterial spore and is unique in that it has been found only in bacterial endospore. This study was aim to evaluate the environmental stress on DPA production in Bacillus cereus PTCC1015.   Materials and Methods: In this experimental study the effects of environmental stresses including temperature, ethanol, NaCl and pH on the production of DPA by Bacillus cereus PTCC 1015 were evaluated by colorimetric assay (the color complex formed by interaction of ferrous iron with dipicolinic acid) and comparison with standard curves. Results: The results showed that the amount of DPA in B. cereus decreased upon increase in acidic condition and salt concentration in the medium. DPA formation increased at alkaline pH 8-10. DPA formation decreased in the medium containing 5-55% of ethanol. DPA formation was higher in optimum temperature at 30 ºCin comparison to the reference strains. The cell concentration decreased at 90 ºC and level of DPA detected in this stage. Conclusion: In stressful condition, DPA formation significantly reduced and these properties can be used in food and dairy industries to control spore production of Bacillus cereus.

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