Abstract: Novel microorganisms are provided that efficiently convert xylose (or xylulose) alone or in combination with a carbon substrate to produce xylitol. In certain embodiments, E. coli are engineered to include a mutant crp gene as well as deletion of the xylB gene. The microorganisms of the invention are particularly advantageous because they serve as biocatalysts for the efficient and scalable conversion of biomass-derived sugars into xylitol.

Abstract: The invention relates to novel variants of cytochrome P450 oxygenases. These variants have an improved ability to use peroxide as an oxygen donor as compared to the corresponding wild-type enzyme. These variants also have an improved thermostability as compared to the cytochrome P450 BM-3 F87A mutant. Preferred variants include cytochrome P450 BM-3 heme domain mutants having I58V, F87A, H100R, F107L, A135S, M145A/V, N239H, S274T, L324I, I366V, K434E, E442K, and/or V446I amino acid substitutions.

Abstract: The invention relates to novel variants of cytochrome P450 oxygenases. These variants have at least one mutation improving their ability to use peroxide as an oxygen donor as compared to the corresponding wild-type enzyme. The variants also have at least one mutation improving thermostability as compared to the parent enzyme or corresponding wild-type enzyme. Preferred variants include cytochrome P450 BM-3 heme domain variants having L52I, I58V, F87A, H100R, S106R, F107L, A135S, M145A/V, A184V, N239H, S274T, L324I, V340M, I366V, K434E, E442K, and/or V446I amino acid substitutions.