We identified a number of genes that encode for components of the ni­trogen assimilatory pathway (Table 4). Genes that encode for enzymes catalyzing the reduction of NO3- to NH4+ and the biosynthesis of nitrogen­carrying amino acids were strongly expressed under nitrogen limitation [32,33]. Along with the pentose phosphate pathway, these genes were among the most up-regulated genes in — N cells of N. oleoabundans. The increased expression of these genes was consistent with their role in nitro­gen uptake and assimilation, and the nitrogen limited growth environment from which cells were derived.