preferred_name: a 1-[(6Z,9Z,12Z)-octadectrienoyl]-2-acyl-glycerolipid + 2 reduced [2Fe-2S]-[ferredoxin] + O2 + 2 H(+) => a 1-[(6Z,9Z,12Z,15Z)-octadectetraenoyl]-2-acyl-glycerolipid + 2 oxidized [2Fe-2S]-[ferredoxin] + 2 H2O