A sequential statistical strategy was used to optimize tannase production from Aspergillus tubingensis
using tea stalks by solid-state fermentation.
First, using a Plackett–Burman design, inoculum size and incubation time (among seven
tested variables) were identified as the most significant factors for tannase yield. The effects of
significant variables were further evaluated through a single steepest ascent experiment and
central composite design with response surface analysis. Under optimal conditions, the
experimental value of 84.24 units per gram of dry substrate (U/gds) closely matched the predicted value of
The result of the statistical approach was 2.09 times higher than the basal medium (40.22 U/gds).
The results were fitted onto a second-order polynomial model with a correlation coefficient (R2
) of 0.9340,
which implied an adequate credibility of the model.