Retamycin production by immobilized cells of Streptomyces olindensis ICB20 in repeated-batch cultures

Repeated-batch cultures of Ca-alginate immobilized cells of Streptomyces olindensis ICB20 for retamycin production were carried out in two different bioreactors: a basket-type stirred tank reactor (BSTR) and a bubble column reactor (BCR). Higher average values of retamycin content (R) and productivity (PR) were achieved in the BSTR cultures (about 1.7 AU and 0.031 AU h−1, respectively) compared to those obtained in the BCR cultures (about 0.6 AU and 0.012 AU h−1, respectively). The BCR, on the other hand, presented significantly better operation stability than the BSTR, which makes the former much more promising regarding future industrial applications.