Suspended rice particles for cultivation of Monascus purpureus in a tower-type bioreactor

Cultivation of Monascus purpureus (CCRC 31615) for the production of natura l pigments was investigated. Traditionally, Monascus species were grown on rice by solid-state culture. For large-scale cultivation, solid-state cultu res were associated with some problems such as contamination and scale-up. By using submerged cultures with rice particles, a stirred-tank fermentor w as not suitable for submerged cultures as the impeller tended to break the particles into small pieces. A conventional bubble column was also unsuitab le as its mixing capability was poor. In the present study, a modified bubb le column with wire-mesh draft tubes was employed for the cultivation of M. purpureus. The proposed column had a shorter mixing time and a higher oxyg en transfer rate relative to the conventional bubble column. The production of pigments using the proposed column was up to 80% higher than that achie ved using the conventional bubble column.