Dual feeding strategy for the production of α-amylase by Bacillus caldolyticus using complex media

In this study, the objective was to investigate an exponential feeding strategy for fed-batch production of thermostable α-amylase (E.C. 3.2.1.1.) from the Bacillus caldolyticus (DSM405). The parameters for establishing compositions of feed media and feeding rate were obtained by statistical analysis of batch and continuous shake flask experiments. These parameters were casitone to starch ratio of 2.67 gcasitone gstarch−1, maintenance coefficient 0.174 gcasitone gDW−1 h−1, cell yield 0.62 gDW gcasitone−1 and μopt = 0.2 h−1. The exponentially fed fermentation resulted in yield of 120 U ml−1 α-amylase that was thermostable up to 105 °C. Results of the exponentially fed fermentation have been discussed in the light of a feed-back controlled fed-batch fermentation reported earlier by the authors. A comparison of the temperature and pH effects on amylase produced by B. caldolyticus and on several other commercially available amylases has also been presented.