Bacterium producing monophosphoryl lipid A and method of producing monophosphoryl lipid A by using bacterium

A recombinant bacterium that produces monophosphoryl lipid A (MLA) not conjugated to a 2-keto-3-deoxy-D-manno-octulosonate (Kdo) moiety,

• wherein the recombinant bacterium is transformed with at least one exogenous polynucleotide encoding a Lipid A-1 phosphatase (LpxE) polypeptide,
• wherein the recombinant bacterium is modified by 1) transformation with at least one of an exogenous polynucleotide encoding a lipid A biosynthesis lauroyltransferase (LpxL) polypeptide, an exogenous polynucleotide encoding a lipid A biosynthesis myristoyltransferase (LpxM) polypeptide, or a combination thereof, or 2) a genetic modification in a 5′-non-coding sequence or a 3′-non-coding sequence for an endogenous polynucleotide encoding a LpxL polypeptide, an endogenous polynucleotide encoding a LpxM polypeptide, or a combination thereof, wherein the recombinant bacterium has increased expression of the polynucleotide encoding the LpxL polypeptide, the polynucleotide encoding the LpxM polypeptide, or a combination thereof as compared to a corresponding recombinant bacterium without the modification of 1) and 2), and
• wherein the recombinant bacterium has a disruption in a gene encoding a polypeptide involved in Kdo biosynthesis selected from a gene encoding a KdtA polypeptide, a gene encoding a KdsB polypeptide, a gene encoding a KdsC polypeptide, a gene encoding a KdsA polypeptide, a gene encoding a GutQ polypeptide, a gene encoding a KpsF polypeptide, a gene encoding a KpsU polypeptide, a gene encoding a KdsD polypeptide, or a combination thereof.