A recombinant microbial host cell comprising: (a) at least one multizyme which comprises a polypeptide having at least one delta-9 elongase linked to at least one delta-8 desaturase; (b) at least one peroxisome biogenesis factor protein whose expression has been down-regulated; (c) at least two polypeptides having at least lysophosphatidic acid acyltransferase ["LPAAT"] activity; and (d) at least one polypeptide having at least phospholipid:diacylglycerol acyltransferase ["PDAT"] activity, further comprising at least one mutant delta-9 elongase polypeptide, wherein said cell has been transformed with a polynucleotide encoding said at least one mutant delta-9 elongase polypeptide, wherein said mutant delta-9 elongase polypeptide comprises an amino acid sequence as set forth in SEQ ID NO:1, wherein SEQ ID NO:1 differs from SEQ ID NO:3 by at least one amino acid mutation, said at least one amino acid mutation being selected from the group consisting of: i) a L35G mutation; ii) a L35F mutation; iii) a L35G mutation and at least one other mutation selected from the group consisting of: S9A, S9D, S9G, S9I, S9K, S9Q, Q12K, A21D, A21T, A21V, V32F, Y84C, L108G, G127L, W132T, M143N, M143W, L161T, L161Y, W168G, I179M, I179R, C236N, Q244N, A254W and A254Y; iv) L35G, A21V, L108G and I179R mutations; v) L35G, W132T and I179R mutations; vi) L35G, S9D, Y84C and I179R mutations; vii) L35G, Y84C, I179R and Q244N mutations; viii) L35G, A21V, W132T, I179R and Q244N mutations; ix) L35M and Q107E mutations; x) K58R and I257T mutations; xi) a D98G mutation; and xii) L130M and V243A mutations. (a) at least one multizyme which comprises a polypeptide having at least one delta-9 elongase linked to at least one delta-8 desaturase; (b) at least one peroxisome biogenesis factor protein whose expression has been down-regulated; (c) at least two polypeptides having at least lysophosphatidic acid acyltransferase ["LPAAT"] activity; and (d) at least one polypeptide having at least phospholipid:diacylglycerol acyltransferase ["PDAT"] activity, further comprising at least one mutant delta-9 elongase polypeptide, wherein said cell has been transformed with a polynucleotide encoding said at least one mutant delta-9 elongase polypeptide, wherein said mutant delta-9 elongase polypeptide comprises an amino acid sequence as set forth in SEQ ID NO:1, wherein SEQ ID NO:1 differs from SEQ ID NO:3 by at least one amino acid mutation, said at least one amino acid mutation being selected from the group consisting of: i) a L35G mutation; ii) a L35F mutation; iii) a L35G mutation and at least one other mutation selected from the group consisting of: S9A, S9D, S9G, S9I, S9K, S9Q, Q12K, A21D, A21T, A21V, V32F, Y84C, L108G, G127L, W132T, M143N, M143W, L161T, L161Y, W168G, I179M, I179R, C236N, Q244N, A254W and A254Y; iv) L35G, A21V, L108G and I179R mutations; v) L35G, W132T and I179R mutations; vi) L35G, S9D, Y84C and I179R mutations; vii) L35G, Y84C, I179R and Q244N mutations; viii) L35G, A21V, W132T, I179R and Q244N mutations; ix) L35M and Q107E mutations; x) K58R and I257T mutations; xi) a D98G mutation; and xii) L130M and V243A mutations. i) a L35G mutation; ii) a L35F mutation; iii) a L35G mutation and at least one other mutation selected from the group consisting of: S9A, S9D, S9G, S9I, S9K, S9Q, Q12K, A21D, A21T, A21V, V32F, Y84C, L108G, G127L, W132T, M143N, M143W, L161T, L161Y, W168G, I179M, I179R, C236N, Q244N, A254W and A254Y; iv) L35G, A21V, L108G and I179R mutations; v) L35G, W132T and I179R mutations; vi) L35G, S9D, Y84C and I179R mutations; vii) L35G, Y84C, I179R and Q244N mutations; viii) L35G, A21V, W132T, I179R and Q244N mutations; ix) L35M and Q107E mutations; x) K58R and I257T mutations; xi) a D98G mutation; and xii) L130M and V243A mutations.