The focus in the present work was on the continuous β‐carotene production from free fatty acids supplied by the soap stock as a sole carbon source for Rhodotorula rubra cells in an airlift bioreactor. The effects of dilution rate on the cell growth...
The focus in the present work was on the continuous β‐carotene production from free fatty acids supplied by the soap stock as a sole carbon source for Rhodotorula rubra cells in an airlift bioreactor. The effects of dilution rate on the cell growth and β‐carotene production were studied by both freely suspended‐ and immobilized‐cell systems in the chemostat operations. The results showed that the immobilization of the cell on natural sponge of loofah significantly increased the optimum and maximum dilution rates from 0.0375 to 0.05 hr−1 and 0.055 to 0.150 hr−1, respectively. The immobilization process has practical role in balancing of cell proliferation in the matrix and wash out the grown cells containing β‐carotene from the bioreactor where β‐carotene productivity was enhanced from 5.4 to 23.4 mg L−1 hr−1 using the immobilized cell technology.