Engineering the production of a conformational variant of occidiofungin that has enhanced inhibitory activity against fungal species

A method of increasing, in a microorganism producing occidiofungin, production of occidiofungin diastereomers/conformers corresponding to the diastereomers/conformers having the total correlation spectroscopy (TOCSY) fingerprint set forth in FIG. 5C as the green NH correlations, the method comprising:

• genetically manipulating the microorganism to increase thioesterase activity of an occidiofungin gene N (ocfN) product (OcfN) within the microorganism, wherein the genetic manipulation of the microorganism comprises:
• increasing the OcfN thioesterase activity by expressing a gene encoding the ocfN thioesterase in a multicopy plasmid;
• increasing the OcfN thioesterase activity by chromosomal integration of one or more additional copies of a gene encoding the OcfN thioesterase into the chromosome of the microorganism;
• and/or
• substituting of the native promoter associated with the gene encoding the OcfN thioesterase with a promoter that increases the expression level of the occidiofungin gene N (ocfN) relative to the native promoter,
• and wherein the increase in the OcfN thioesterase activity is as compared to a reference microorganism without the increase in OcfN thioesterase activity cultured under the same conditions.