The disclosure relates to mutant gene(s) that confer upon microorganisms that express them an improved capacity to utilize xylose and improved capacity to co-utilize glucose and xylose thereby resulting in improved growth of the microorganism. Further encompassed are methods of producing fatty acids and fatty acid derivatives from cellulosic biomass, xylose, and/or a glucose/xylose mix by employing the host cells expressing the engineered XylR variants and compositions of biologically produced fatty acids and fatty acid derivatives.

Provided herein are non-naturally occurring microbial organisms having a pathway for production of (3R)-hydroxybutyl (3R)-hydroxybutyrate, wherein the organism can further include a (R)-1,3-butanediol pathway, a (3R)-hydroxybutyrate pathway, a (3R)-hydroxybutyryl-CoA pathway, an acetoacetate pathway, an acetoacetyl-CoA pathway, a (3R)-hydroxybutyl-ACP pathway, or an acetoacetyl-ACP pathway. Additionally provided are methods and processes for producing and isolating (3R)-hydroxybutyl (3R)-hydroxybutyrate using the microbial organisms, and various compositions having the (3R)-hydroxybutyl (3R)-hydroxybutyrate. Still further provided are methods of treating or preventing a disease, disorder or condition using the (3R)-hydroxybutyl (3R)-hydroxybutyrate produced by the microbial organisms of the invention.

Recombinant microbial cells are provided which have been engineered to produce fatty acid derivatives having linear chains containing an odd number of carbon atoms by the fatty acid biosynthetic pathway. Also provided are methods of making odd chain fatty acid derivatives using the recombinant microbial cells, and compositions comprising odd chain fatty acid derivatives produced by such methods.

A recombinant cell for producing a fatty acid ester. The recombinant cell is genetically engineered to produce a reduction in free fatty acids compared to a cell that has not been similarly genetically engineered. Methods for producing fatty acid esters while decreasing free fatty acid production are also described.

Provided herein are non-naturally occurring microbial organisms having a pathway for production of (3R)-hydroxybutyl (3R)-hydroxybutyrate, wherein the organism can further include a (R)-1,3-butanediol pathway, a (3R)-hydroxybutyrate pathway, a (3R)-hydroxybutyryl-CoA pathway, an acetoacetate pathway, an acetoacetyl-CoA pathway, a (3R)-hydroxybutyl-ACP pathway, or an acetoacetyl-ACP pathway. Additionally provided are methods and processes for producing and isolating (3R)-hydroxybutyl (3R)-hydroxybutyrate using the microbial organisms, and various compositions having the (3R)-hydroxybutyl (3R)-hydroxybutyrate. Still further provided are methods of treating or preventing a disease, disorder or condition using the (3R)-hydroxybutyl (3R)-hydroxybutyrate produced by the microbial organisms of the invention.

The disclosure relates to mutant gene(s) that confer upon microorganisms that express them an improved capacity to utilize xylose and improved capacity to co-utilize glucose and xylose thereby resulting in improved growth of the microorganism. Further encompassed are methods of producing fatty acids and fatty acid derivatives from cellulosic biomass, xylose, and/or a glucose/xylose mix by employing the host cells expressing the engineered XylR variants and compositions of biologically produced fatty acids and fatty acid derivatives.