Abstract: In alternative embodiments, provided are genetically or recombinantly engineered nitrogen-fixing, nitrogenase-expressing bacteria capable of enzymatically synthesizing hydrocarbons and generating hydrogen and carbon monoxide, and for carbon dioxide and/or carbon monoxide recycling, and compositions (e.g., bioreactors and devices) for using them, and methods for making and using them. In alternative embodiments, the genetically or recombinantly engineered nitrogen-fixing, nitrogenase expressing bacteria used to practice embodiments provided herein include nitrogen-fixing diazotrophs such as nitrogen-fixing bacteria of the family Pseudomonadaceae, or the genus Azotobacter, including Azotobacter vinelandii, for the whole cell synthesis of hydrocarbons and generating hydrogen and carbon monoxide, and for the recycling of carbon dioxide and/or carbon monoxide.