Provided herein are Metschnikowia species that produce xylitol from xylose when cultured, as well as methods to make and use these Metschnikowia species.

The present invention provides for novel metabolic pathways to detoxify biomass-derived acetate via metabolic conversion to ethanol, acetone, or isopropanol. More specifically, the invention provides for a recombinant microorganism comprising one or more native and/or heterologous enzymes that function in one or more first engineered metabolic pathways to achieve: (1) conversion of acetate to ethanol; (2) conversion of acetate to acetone; or (3) conversion of acetate to isopropanol; and one or more native and/or heterologous enzymes that function in one or more second engineered metabolic pathways to produce an electron donor used in the conversion of acetate to less inhibitory compounds; wherein the one or more native and/or heterologous enzymes is activated, unregulated, or downregulated.

Presented herein are oleaginous strains of yeast such as Saccharomyces cerevisiae that have been modified to allow for xylose utilization. Such strains are also modified to allow for higher lipid accumulation utilizing a broad range of sugar monomers such as those released during pretreatment and enzymatic saccharification of lignocellulosic biomass. Methods of producing lipids and ethanol using these yeast strains are also disclosed.

The present invention relates to a method of preparing a strain of sugar fermenting Saccharomyces cerevisiae with capability to ferment xylose, wherein said method comprises different procedural steps. The method comprises mating a first sporulated Saccharomyces cerevisiae strain with a second Saccharomyces cerevisiae haploid strain. Thereafter, screening for mated cells is performed, growing such mated cells, and verifying that mated cells exhibit basic morphology by microscopic inspection. Thereafter, creation of a mixture of the mated cells is performed, subjecting the mixture to continuous chemostat lignocellulose cultivation and obtaining the sugar fermenting Saccharomyces cerevisiae cells with capability to ferment xylose is performed. The invention also comprises strains obtained by said method.

Provided herein are Metschnikowia species that produce xylitol from xylose when cultured, as well as methods to make and use these Metschnikowia species.

The present invention relates to a method of preparing a strain of sugar fermenting Saccharomyces cerevisiae with capability to ferment xylose, wherein said method comprises different procedural steps. The method comprises mating a first sporulated Saccharomyces cerevisiae strain with a second Saccharomyces cerevisiae haploid strain. Thereafter, screening for mated cells is performed, growing such mated cells, and verifying that mated cells exhibit basic morphology by microscopic inspection. Thereafter, creation of a mixture of the mated cells is performed, subjecting the mixture to continuous chemostat lignocellulose cultivation and obtaining the sugar fermenting Saccharomyces cerevisiae cells with capability to ferment xylose is performed. The invention also comprises strains obtained by said method.

Disclosed is a method for the isomerization of glucose by reduction to sorbitol and subsequent oxidation to fructose, in which the redox cofactors NAD.sup.+/NADH and NADP.sup.+/NADPH are regenerated in a one-pot-reaction, wherein one of the two redox cofactors is obtained in the reduced form thereof and the other redox cofactor in the oxidized form thereof as a result of at least two additional enzymatically catalyzed redox reactions (product forming reactions) taking place in the same reaction batch, wherein a) in the regeneration reaction, which transfers the reduced cofactor back to its originally oxidized form, oxygen or a compound of the general formula R.sub.1C(O)COOH is reduced, and b) in the regeneration reaction, which transfers the oxidized cofactor back to its originally reduced form, a compound of the general formula R.sub.2CH(OH)R.sub.3 is oxidized, wherein R.sub.1, R.sub.2 and R.sub.3 have different meanings in the compounds, characterized in that a mixture of glucose and fructose is used as a starting material. Furthermore, the use of fructose thus produced in a method for producing furan derivatives is disclosed.

A method for the enzymatic production of D-fructose from D-glucose in a one-pot synthesis, wherein D-glucose is oxidized enzymatically to D-glucosone and D-glucosone is reduced enzymatically to D-fructose and the use of the D-fructose produced in this way for the production of furan derivatives.

Provided herein are non-naturally occurring microbial organisms having increased xylose metabolism and increased production of ethanol using xylose as a substrate, as well as methods to make and use these microbial organisms to produce ethanol.

Provided herein are Metschnikowia species that produce xylitol from xylose when cultured, as well as methods to make and use these Metschnikowia species.