to evaluate the factors significantly affecting the production of
c-PGA by B. subtilis RKY3, Plackett–Burman experimental design
was employed. The experiments were carried out according to
the experimental matrix as shown in Table 1, and c-PGA production
was determined as a response. A wide variation in c-PGA production (0–7.43 g l1
) was observed, reflecting the importance
of medium optimization to get a high yield of a product.