Fig. 1

Production of FFAs from metabolically engineered R. sphaeroides in a two-phase culture system with dodecane. R. sphaeroides was recombinantly engineered to overproduce FabH, PlsX, PlsY, and PlsC in the cytoplasm and A. thaliana PLA2 in the periplasm. The long-chain FFAs released by R. sphaeroides were directed and localized to the dodecane layer. FFA sequestration in the dodecane layer alleviated the inhibitory effect of FFAs on cell growth, further elevating the FFA productivity of the cells. Multiple biosynthetic steps are illustrated by a series of connecting arrows, whereas a putative LPL acyltransferase activity of PlsC, which may form PL from LPL using acyl-ACP, is shown by dotted arrows. The PLs and LPLs of the inner membrane, which are the substrate and product of PLA2, respectively, are highlighted in boxes; the PLs of the outer membrane are also thought to be used by PLA2. DHAP, dihydroxyacetone phosphate; ACP, acyl carrier protein; FabH, β-ketoacyl-ACP synthase; AccABCD, acetyl-CoA carboxylase; FabD, malonyl-CoA:ACP transacylase; GpsA, glycerol-3-phosphate dehydrogenase; GlpK, glycerol kinase; PlsX, phosphate acyltransferase; PlsY, glycerol-3-phosphate acyltransferase; PlsC, 1-acyl-sn-glycerol-3-phosphate acyltransferase; LPS, lipopolysaccharide; LPL, lysophospholipid; PL, phospholipid; PLA2, phospholipase A2 of A. thaliana