The invention is related to an inducible promoter for improved and regulated gene expression, useful in synthetic biology and metabolic engineering. In particular, the present invention relates to a nucleotide sequence comprising the regulatory regions of an erythritol- and erythrulose-inducible promoter in yeast and uses thereof in an expression system thus allowing an improved and regulated gene expression and production of gene product.

The present invention relates to a recombinant microbial host for the production of xylitol, the recombinant microbial host containing a nucleic acid sequence encoding a NAD.sup.+-specific D-arabitol 4-oxidoreductase (EC 1.1.1.11) using D-arabitol as substrate and producing D-xylulose as product, and a nucleic acid sequence encoding a NADPH-specific xylitol dehydrogenase using D-xylulose as substrate and producing xylitol as product.

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.

The present invention relates to a recombinant microbial host for the production of xylitol, the recombinant microbial host containing a nucleic acid sequence encoding an NAD+-specific D-arabitol 4-oxidoreductase (EC 1.1.1.11) using D-arabitol as substrate and producing D-xylulose as product, and a nucleic acid sequence encoding an NADPH-specific xylitol dehydrogenase using D-xylulose as substrate and producing xylitol as product.

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.

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

The invention relates to engineering microbial cells for utilization of cellulosic materials as a carbon source, including xylose.

The present application discloses the identification of the novel K. marxianus xylose transporter genes KHT105 and RAG4, as well as the identification of a novel set of I. orientalis pentose phosphate pathway genes The present application further discloses a series of genetically modified yeast cells comprising various combinations of arabinose fermentation pathways, xylose fermentation pathways, pentose phosphate pathways, and/or xylose transporter genes, and methods of culturing these cells to produce ethanol in fermentation media containing xylose.