A comparative study on the production of amidase using immobilized and dehydrated immobilized cells of Pseudomonas putida MTCC 6809

Pseudomonas putida MTCC 6809, a plant growth promoting rhizobacteria producing amidase was isolated from the rhizosphere of Pisum sativum. The cells were immobilized in sodium alginate for the production of amidase and the effect of dehydration on immobilized beads were studied. Optimization of process parameters for amidase production was carried out to enhance enzyme production using immobilized cells. From the results it is clear that 2% and 3% (w/v) of alginate were suitable for amidase production with 12.8 and 13 U/ml activity, respectively after 36 h of incubation. Among the various substrates studied acetamide (2% w/v) was a good inducer of amidase. It was observed that immobilized catalysts could be recycled up to five batches. Amidase production was observed in both free and immobilized cells, nevertheless immobilization is much favored in comparison to free cells, as it leads to reusability of beads, lesser contamination, consistent amidase production and adaptability to wide range of culture conditions. The relative enzyme activity with the dehydrated beads was only 27% in comparison to hydrated beads, it is possible to pack considerably more into a fixed volume as the relative volume of dehydrated beads is 20%. Even though consistent amidase production was difficult to achieve using dehydrated beads, which may have certain advantages like less chances for microbial contamination and easy to transport.