3. The viewpoint of cell-economy The economy systems of microbial cells have been developing into competent economy in a long, long process of inartificial selection. In the case of microbial breeding and controlled fermentation, aiming at the production of target- product, the metabolic flow should be regulated for earning bioenergy on which the cells rely for living, and for the accumulation of target-product or desirable products outside cells; in that situation the state of cell-economy should be oriented. The transformation from competitive-type economy into guiding-type economy is dependent upon information guidance of the genetic and circumstance factors, nevertheless the over-deviation from competent economy may bring down on a crash of cell-economy3. The viewpoint of cell-economy The economy systems of microbial cells have been developing into competent economy in a long, long process of inartificial selection. In the case of microbial breeding and controlled fermentation, aiming at the production of target￾product, the metabolic flow should be regulated for earning bioenergy on which the cells rely for living, and for the accumulation of target-product or desirable products outside cells; in that situation the state of cell-economy should be oriented. The transformation from competitive-type economy into guiding-type economy is dependent upon information￾guidance of the genetic and circumstance factors, nevertheless the over-deviation from competent economy may bring down on a crash of cell-economy