A microorganism comprising at least a first exogenous nucleic acid sequence that encodes a polypeptide selected from a thioesterase, an acyl carrier protein, a fatty acyl-CoA binding protein, a fatty acyl-CoA reductase, and a fatty acid desaturase, wherein the microorganism cell converts gaseous CO2 and/or gaseous H2 and/or syngas into one or more lipids or hydrocarbons,
- wherein the microorganism is Rhodococcus sp. DSM 3346 or DSM 364, or Rhodococcus opacus DSM 43205 or DSM 43206, and
- wherein the microorganism produces and/or secretes lipids in a quantity that is 10% or more of the dry cell mass.