The previously mentioned aeration-controlled scheme (Section 2) has a short redox potentialcontrolled period. In order to extend controlled duration, two schemes were suggested: 1) glucosecontrolled feeding scheme (GCFS) where glucose was supplemented along with dissolved oxygen presented in the feed stream; and 2) a combined chemostat and aeration-controlled scheme (CCACS) where a constant glucose was fed along with air supply determined by redox potential-controlled device.