A strain of Escherichia coli has been genetically engineered to produce human protein. A batch culture is started by inoculating 12 g of cells into a 100-litre bubble column fermenter containing 10 g 1^- 1 glucose. The culture does not exhibit a lag phase. The maximum specific growth rate of the cells is 0.9 h^-1; the biomass yield from glucose is 0.575 g g^-11. Estimate the time required to reach stationary phase. 2. What will be the final cell density if the fermentation is stopped after only 70% of the substrate is consumed