Materials and methods for controlling limitation conditions in product biosynthesis for non-phb generating species of the genera ralstonia or cupriavidus and organisms related thereto

A method for increasing the yield of an extracellular product in an aerobic fermentation system, the method comprising:

• providing an organism belonging to a genus selected from the group consisting of Cupriavidus and Ralstonia, wherein the organism has been modified to exhibit a decreased synthesis of polyhydroxyalkanoate relative to that of the corresponding wild type organism, wherein the organism has been modified to exhibit an increased synthesis of the extracellular product relative to that of the corresponding wild type organism, wherein the organism comprises one or more modified or exogenous promoters, and wherein the promoters are each independently a constitutive promoter or an inducible promoter activated by a nutrient limitation condition;
• culturing a population of the organism in the fermentation system;
• independently controlling the concentration of each of one or more selected limiting nutrients in at least one reactor of the fermentation system, wherein each limiting nutrient independently has a limiting concentration;
• and
• operating the fermentation system under continuous fermentation conditions suitable for synthesis of the extracellular product by the organism, wherein the continuous fermentation conditions comprise concentrations of the selected limiting nutrients less than their respective limiting concentrations in the at least one reactor, and wherein the yield of the extracellular product is increased relative to that synthesized by the organism under otherwise corresponding continuous fermentation conditions comprising concentrations of at least one of the selected limiting nutrients above its limiting concentration in each reactor of the fermentation system.