Catalyzes the second step in the formation of ornithine lipids, which are phosphorus-free membrane lipids (Probable). Uses acyl-acyl carrier protein (acyl-AcpP) as an acyl donor and converts lyso-ornithine lipid (LOL) into ornithine lipid (OL) (By similarity). It can also act as an alternate acyl-sn-glycerol-3-phosphate acyltransferase (AGPAT) to ensure glycerophospholipid production (PubMed:17921310). a fatty acyl-[ACP] + a lyso-ornithine lipid = an N(2)-[(3R)-3-(acyloxy)acyl]-L-ornithine lipid + holo-[ACP] a 1-acyl-sn-glycero-3-phosphate + a fatty acyl-[ACP] = a 1,2-diacyl-sn-glycero-3-phosphate + holo-[ACP] Lipid metabolism. Phospholipid metabolism. Mutant lacking this gene is unable to produce ornithine lipids. Belongs to the 1-acyl-sn-glycerol-3-phosphate acyltransferase family. OlsA subfamily.