NOVELTY - A transformed microorganism capable of: (a) a higher xylose isomerase activity than the equivalent microorganism prior to transformation; and/or (b) a higher growth rate in or on a growth medium comprising xylose than the equivalent microorganism prior to transformation; and/or (c) a faster metabolism of xylose than the equivalent microorganism prior to transformation; and/or (d) a higher production of ethanol when grown anaerobically on xylose as the carbon source than the equivalent microorganism prior to transformation, is new.    USE - The microorganism is useful for producing a product derived from xylose selected from xylulose, xylulose-5-phosphate, ethanol, aromatic amino acids, lactic acid, succinic acid, acetic acid, acetaldehyde, furfural, itaconic acid, glutamic acid, citric acid, cresol, lysine, 3-hydroxypropionic acid, poly-3-hydroxyalkanoates, protocatechuic acid, pyrocatechol, guaiacol, veratrol, resveratrol, vanillin, vanillic acid, vanillyl alcohol, muconic acid, adipic acid, 4-hydroxybenzoic acid, 4-hydroxybenzaldehyde, 4-methoxybenzoic acid, 4-aminobenzoate, 4-hydroxyaniline, 4-methoxyaniline, quinol, anisole, phenol, anthranilic acid, 3-hydroxyanthranilate, 2,3-dihydroxybenzoic acid, 2-aminophenol, 1,4-cyclohexanedione, isoprene and styrene. The microorganism is useful for producing a biofuel (all claimed).    ADVANTAGE - The present invention relates to the transformation (engineering) of microorganisms, such as those of the Saccharomyces family, to enable the microorganisms to metabolize xylose. This increases the efficiency of the microorganisms to produce ethanol from xylose-containing feedstock. It also increases the efficiency of microorganisms to produce other natural or engineered metabolites derived from intermediates in the pentose phosphate pathway. The nucleotide sequence encoding xylose isomerase is derived from a mesophilic organism and/or is capable of high activity at mesophilic temperatures. The microorganisms can produce an active xylose isomerase and biofuels (such as ethanol). By using the microorganisms, biofuels can be produced from waste materials such as agricultural wastes. With the present invention there is no need (or there is a reduced need) to use materials (such as sugar cane extract, sugar beet extract, sorghum starch, maize starch, wheat starch or corn starch) which could otherwise be used as a food source for humans and/or as an animal feed. The microorganisms enable the optimum use of the sugars released by hydrolysis of lignocellulosic material by the fermentation of pentose sugars, in particular xylose. The present invention enables the production of a biofuel which is more carbon dioxide (CO2) neutral in comparison with petroleum based transportation fuel. With the present invention, CO2 emissions will be low (even lower) when producing the biofuel than compared to the production of typical petroleum based transportation fuel (fossil fuels).    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are:    (1) an inoculum comprising a microorganism above;    (2) a culture medium comprising a microorganism above;    (3) a method for preparing a transformed microorganism above;    (4) a fermentation method by culturing in a culture medium a microorganism above prepared by the method of (3);    (5) a method for producing a product derived from xylose by culturing in a culture medium a microorganism above prepared by the method of (3);    (6) a method for producing a biofuel by culturing in a culture medium a microorganism above prepared by the method of (3); and    (7) a biofuel obtained by the method of (6).