The present invention provides for a method for producing a rhamnolipid, the method comprising: (a) providing a genetically modified host cell comprising one or more of RhlYZAB capable of expression in the host cell in a growth or culture medium; (b) growing or culturing the host cell such that the one or more of RhlYZAB are expressed and a rhamnolipid is produced; and (c) optionally recovering the rhamnolipid from the host cell or from the growth or culture medium. In some embodiments, the host cell is a methanotroph.

Provided herein include methods and compositions for synthesis of Lipid IV.sub.A and derivatives thereof, using a defined set of pathway enzyme, which may be isolated and used to reconstitute all or part of the pathway in a cell-free reaction.

Provided herein include methods and compositions for synthesis of Lipid IV.sub.A and derivatives thereof, using a defined set of pathway enzyme, which may be isolated and used to reconstitute all or part of the pathway in a cell-free reaction.