Abstract: Microorganisms are genetically engineered to continuously co-produce amino acids, high-value, specialized proteins, microbial biomass, chemicals, or any combination thereof by microbial fermentation, particularly by microbial fermentation of a gaseous substrate. The microorganisms are C1-fixing. The production of ethylene, microbial biomass, and heterologous high-value, specialized proteins can be improved. This can be improved by varying promoters or nutrient limiting means.

Abstract: Microorganisms are genetically engineered to continuously co-produce amino acids, proteins, microbial biomass, chemicals, or any combination thereof by microbial fermentation, particularly by microbial fermentation of a gaseous substrate. The microorganisms are C1-fixing. The production of ethylene, microbial biomass, and heterologous tandem repeat proteins can be improved. This can be effected by improved promoters or nutrient limiting means.

Abstract: Methods and microorganisms are genetically engineered to continuously produce ethylene by microbial fermentation, particularly by the microbial fermentation of a gaseous substrate. The microorganisms are C1-fixing. Further, the gaseous substrate comprises CO2 and an energy source. The production of ethylene can be improved by varying promoters or nutrient limiting means.