Surface modified zeolite, a novel carrier material for Azotobacter chroococcum |
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Authors: | Prachi Joshi Sadhana Rayalu Amit Bansiwal Asha A Juwarkar |
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Institution: | (1) Environmental Biotechnology Division, National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur, 440020, India;(2) Environmental Materials Unit, National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur, 440020, India |
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Abstract: | A new immobilization matrix based on zeolite has been developed to immobilize Azotobacter chroococcum, for fixing nitrogen, with an intention to hold the cells in the root zone of the plants and to protect them under stressful
conditions. The matrix has been developed by modifying the surface of the zeolite with surfactant. This enhances the hydrophobicity
of the material and also modifies the surface charge, which in turn enhances the immobilization. Surface modified zeolite-A
(SMZ-A) has been compared with commercial zeolite-A (CZA) for immobilization efficiency. CZA is non-toxic for A. chroococcum but is inefficient to adsorb the cells whereas SMZ-A showed 100% adsorption of the microbial cells wherein it was observed
that for 1 l of broth culture with total viable count of 108 cfu ml−1 cells of A. chroococcum, a minimum dose of 0.7 g SMZ-A and minimum contact time of 10 h is required to achieve 100% adsorption. Adsorption was confirmed
by the cell count and light as well as scanning electron microscopy. Most importantly, the cells adsorbed on SMZ-A could fix
the atmospheric nitrogen up to 13 mg g−1 sucrose consumed, which was comparable with the control (unadsorbed cells), which confirms the survival and nitrogen fixation
activity of the bacteria.
Responsible Editor: Euan K. James. |
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Keywords: | Adsorption Azotobacter chroococcum Carrier material Surface modified zeolite Zeolite |
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