TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preparation: Preparation of the engineered microorganism comprises: introducing at least one expression vector (including an exogenous polynucleotide operably linked to it) inside a host cell (bacterial or fungal cell) by e.g. transformation, electroporation and microinjection; and culturing the host cell containing the polynucleotides encoding the proteins under conditions appropriate for growth of the cells and expression of the polynucleotides. Preferred Components: The polyketide synthase is a MAS or its active fragment comprising an acyl transferase domain and an acyl carrier protein (ACP) domain and a ketide synthase domain. The polyketide synthase or its active fragment comprises: SEQ ID NO: 1 or its homolog, fragment or variant; or an amino acid sequence having at least 80% sequence identity to SEQ ID NO: 3. The MAS further comprises at least a ~b -ketoacyl synthase domain, a dehydratase domain, an enoyl reductase domain and/or a ~b -ketoreductase domain. The MAS is a full length MAS. The MAS is derived from Mycobacterium tuberculosis. The polyketide synthase or its active fragment comprises an amino acid sequence having at least 80% sequence identity to PKS2 (SEQ ID NO: 15), PKS3 (SEQ ID NO: 30), PKS4 (SEQ ID NO: 26), PKS5 (SEQ ID NO: 37), PKS7 (SEQ ID NO: 48) or PKS12 (SEQ ID NO: 61) from Mycobacterium tuberculosis. The long chain fatty acid AMP ligase is FADD28. The FADD28 is derived from Mycobacterium tuberculosis. The long chain fatty acid AMP ligase comprises SEQ ID NO: 72 or its homolog, active fragment or variant. The long chain fatty acid AMP ligase comprises an amino acid sequence having at least 80% sequence identity to SEQ ID NO: 72. The long chain fatty acid AMP ligase comprises an amino acid sequence having at least 80% sequence identity to FADD21 (SEQ ID NO: 72), FADD23 (SEQ ID NO: 74), or FADD24 (SEQ ID NO: 75) from Mycobacterium tuberculosis. The EM1 further comprises an exogenous or overexpressed ester synthase, where the ester synthase catalyzes the transesterification of an MMBFA covalently bound to the ACP domain of MAS with an acceptor alcohol to produce an MMBFA ester. The ester synthase is PAPA5. The ester synthase comprises SEQ ID NO: 76 or its homolog, active fragment or variant. The ester synthase comprises an amino acid sequence having at least 80% sequence identity to SEQ ID NO: 76. The PAPA5 is derived from Mycobacterium tuberculosis. The ester synthase comprises an amino acid sequence having at least 80% sequence identity to PAPA1 (SEQ ID NO: 78), PAPA3 (SEQ ID NO: 77) or PAPA4 (SEQ ID NO: 79) from Mycobacterium tuberculosis. The MMBFA synthesis pathway further comprises the substrate to product conversions such as: propionate to propionyl-CoA; propionyl-CoA to methylmalonyl-CoA; and/or acyl-acyl carrier protein to fatty acid. The enzyme that catalyzes the conversion of propionate to propionyl-CoA is a propionyl-CoA synthetase. The propionyl-CoA synthetase is PRPE. The propionyl-CoA synthetase comprises SEQ ID NO: 80 or its homolog, active fragment or variant. The propionyl-CoA synthetase comprises an amino acid sequence having at least 80% sequence identity to SEQ ID NO: 80. The PRPE is derived from Escherichia coli. The enzyme that catalyzes the conversion of propionyl-CoA to methylmalonyl-CoA is an exogenous or overexpressed PCC complex. The PCC complex comprises: any one of SEQ ID NOs: 81-84 or their homologs, active fragments or variants; or an amino acid sequence having at least 80% sequence identity to any one of SEQ ID NOs: 81-84. The PCC complex is derived from: bacteria of the genera Streptomyces, Mycobacterium, Rhodococcus, Nocardia, Pseudomonas, Corynebacterium, Acinetobacter, Brucella or Burkholderia; or Homo sapiens, Acinetobacter baumannii, Brucella suis or Burkholderia glumae; or Streptomyces coelicolor. The PCC complex comprises ACCA1 (SEQ ID NO: 82), PCCB (SEQ ID NO: 83), and PCCE (SEQ ID NO: 84) proteins from Streptomyces coelicolor. The MMBFA synthesis pathway further comprises a methylmalonate to methylmalonyl-CoA substrate to product conversion. The enzyme that catalyzes the conversion of methylmalonate to methylmalonyl-CoA is an exogenous or overexpressed malonyl/methylmalonyl-CoA ligase. The malonyl/methylmalonyl-CoA ligase is derived from Streptomyces coelicolor. The malonyl/methylmalonyl-CoA ligase comprises SEQ ID NO: 85 or its homolog, active fragment or variant. The malonyl/methylmalonyl-CoA ligase comprises an amino acid sequence having at least 80% sequence identity to SEQ ID NO: 85. The MMBFA synthesis pathway further comprises a succinyl-CoA to methylmalonyl-CoA substrate to product conversion. The enzyme that catalyzes the conversion of succinyl-CoA to methylmalonyl-CoA is an exogenous or overexpressed methylmalonyl-CoA mutase/epimerase. The methylmalonyl-CoA mutase/epimerase is derived from Propionibacterium freudenreichii subsp. shermanii. The methylmalonyl-CoA mutase/epimerase comprises SEQ ID NO: 86, SEQ ID NO: 87 and/or SEQ ID NO: 88, or their homolog, active fragment or variant. The methylmalonyl-CoA mutase/epimerase comprises an amino acid sequence having at least 80% sequence identity to any one of SEQ ID NOs: 86-88. The MMBFA synthesis pathway further comprises an exogenous or overexpressed acyl-ACP thioesterase that catalyzes the conversion of acyl-acyl carrier protein to fatty acid. The thioesterase is the TESA protein from E. coli. The thioesterase comprises: SEQ ID NO: 89 or its homolog, active fragment or variant; or an amino acid sequence having at least 80% sequence identity to SEQ ID NO: 89. The MMBFA synthesis pathway further comprises an exogenous or overexpressed phosphopantetheinyl transferase. The 4'-phosphopantetheinyl transferase is a Sft-type 4'-phosphopantetheinyl transferase. The Sft-type 4'-phosphopantetheinyl transferase is derived from Bacillus subtilis. The phosphopantetheinyl transferase comprises: SEQ ID NO: 90 or its homolog, active fragment or variant; or an amino acid sequence having at least 80% sequence identity to SEQ ID NO: 90. The 4'-phosphopantetheinyl transferase gene replaces a genetic locus responsible for propionate catabolism in the microorganism. The EM2 further comprises a PAPA5 ester synthase from Mycobacterium tuberculosis (SEQ ID NO: 76), where the ester synthase catalyzes the transesterification of an MMBFA with an acceptor alcohol to produce an MMBFA ester. The EM3 further comprises a PAPA3 ester synthase from Mycobacterium tuberculosis (SEQ ID NO: 77), where the ester synthase catalyzes the transesterification of an MMBFA with an acceptor alcohol to produce an MMBFA ester. The EM4 further comprises a PAPA1 ester synthase from Mycobacterium tuberculosis (SEQ ID NO: 78), where the ester synthase catalyzes the transesterification of an MMBFA with an acceptor alcohol to produce an MMBFA ester. The EM5 further comprises a PAPA4 ester synthase from Mycobacterium tuberculosis (SEQ ID NO: 79) where the ester synthase catalyzes the transesterification of an MMBFA with an acceptor alcohol to produce an MMBFA ester. The microorganism is bacteria, fungi, yeast or algae. The bacteria is Streptomyces, Rhodococcus, Mycobacterium, Escherichia, Corynebacterium, Pseudomonas, Nocardia or Bacillus, preferably Escherichia coli, Streptomyces coelicolor or Rhodococcus opacus. The yeast is Saccharomyces, Kluyveromyces, Pachysolen, Zygosaccharomyces, Debaryomyces, Pichia, Schizosaccharomyces, Candida, Issatchenkia, Hansenula, Yarrowia, Trichosporon, Rhodotorula or Myxozyma, preferably Saccharomyces cerevisiae, Saccharomyces uvarum, Saccharomyces bayanus, Saccharomyces paradoxus, Saccharomyces castellii, Saccharomyces kluyveri, Kluyveromyces thermotolerans, Kluyveromyces lactis, Kluyveromyces marxianus, Kluyveromyces waltii, Pachysolen tannophilus, Zygosaccharomyces bailii, Zygosaccharomyces rouxii, Debaryomyces hansenii, Debaryomyces carsonii, Pichia pastoris EXAMPLE - An Escherichia coli strain K207-3 containing a Bacillus subtilis sfp gene that enables posttranslational modification of heterologous acyl carrier protein (ACP) proteins or ACP domains was expressed in E. coli. Then, a single copy of the sfp gene under control of the T7 RNA polymerase promoter was integrated in the prpRBCD operon of BL21(DE3). At the same time, the prpE gene was placed under control of an isopropyl-D-thiogalactopyranoside-inducible T7 promoter PrpE can convert propionate into propionyl-CoA, the substrate of the propionyl-CoA carboxylase (PCC) complex. Then a pathway for (2S)-methylmalonyl-CoA biosynthesis was introduced by cloning two (pccA-pccB) of the three components of the PCC complex from Streptomyces coelicolor under the control of the T7 promoter and integrated in the E. coli ygfG gene that codes for a putative methylmalonyl-CoA decarboxylase. Based on this strain, a E. coli derivative was constructed where the three genes of Streptomyces coelicolor PCC complex (accA1-pccB-pccE) were cloned in an operon fashion under the control of the T7 promoter and integrated in the ygfG locus. The pccE gene encodes the c-subunit of PCC and serve as the adaptor protein between ~a and ~b subunits (AccA1 and PccB, respectively) resulting in an complex with enhanced enzyme activity, and thus to obtain an engineered E. coli strain MB01. Then, the mycocerosic acid synthase, papA5 and fadD28 genes from Mycobacterium tuberculosis were cloned in different expression vectors such as the pET serie and pBAD33. Plasmids pRT23 and pMB09 were introduced via transformation into E. coli MB01 strain.