Industrial production of protein based products such as enzymes and pharmaceutical proteins is carried out in cell factories, organisms optimized to provide maximum yield through fine tuned adjustment of their metabolism. Even modest increases in the yield will have large societal value, not only in form of cheaper products (such as food, consumer products and drugs) and bigger earnings, but will also significantly contribute to a more sustainable and a green production. Improvement of cell factories therefore holds a large potential for growth on the long run. However, traditional optimization techniques, based on the class of genes encoding proteins, have been applied to such an extent that real improvements no longer seem realistic despite that current protein yields are significantly below the theoretical carbon yield. Conversely, the often ignored class of genes not coding for proteins, the non-coding RNAs (ncRNAs) have not been explored for optimization and thus hold a completely untouched potential, in part because ncRNA often is involved in regulation.