摘要:
Provided is a method for producing xylonic acid from xylose with a recombinant fungal strain that is genetically modified to express a xylose dehydrogenase gene, which is able to convert xylose to xylonolactone, which is spontaneously or enzymatically hydrolyzed to xylonic acid. The xylonic acid is excreted outside the host cell. Xylonate production may be coupled with xylitol production. Alternatively, if xylitol production is not desired, its production is reduced by removing the aldose reductase (or specific xylose reductase) enzyme, which converts xylose to xylitol. Expression of a heterologous lactonase encoding gene may result in higher acid concentrations. The method is suitable for producing xylonic acid from a hemicellulose hydrolysate such as hydrolyzed lignocellulosic plant biomass.
摘要:
Provided is a method for producing xylonic acid from xylose with a recombinant fungal strain that is genetically modified to express a xylose dehydrogenase gene, which is able to convert xylose to xylonolactone, which is spontaneously or enzymatically hydrolysed to xylonic acid. The xylonic acid is excreted outside the host cell. Xylonate production may be coupled with xylitol production. Alternatively, if xylitol production is not desired, its production is reduced by removing the aldose reductase (or specific xylose reductase) enzyme, which converts xylose to xylitol. Expression of a heterologous lactonase encoding gene may result in higher acid concentrations. The method is suitable for producing xylonic acid from a hemicellulose hydrolysate such as hydrolysed lignocellulosic plant biomass.
摘要:
The present invention relates to genetic engineering of production microorganisms used in biotechnology to improve their properties so that they produce useful products more efficiently. The microorganisms express at least one enzyme that causes the functional coupling of the oxidation and reduction of substrates by two pyridine nucleotide-linked dehydrogenase reactions with different specificities for the NAD/NADH and NADP/NADPH coenzyme couples and so facilitates the transfer of electrons between the two coenzyme couples through the said substrates. In particular the invention relates to increasing the yields of products such as ethanol or amino acids from carbon and nitrogen sources such as biomass comprising hexoes, pentoses or their polymers.
摘要:
The invention relates to the methods of manufacturing five-carbon sugars and sugar alcohols as well as other compounds derived from pentose-phosphate pathway from readily available substrates such a hexoses using metabolically engineered microbial hosts.
摘要:
The invention relates to the methods of manufacturing five-carbon sugars and sugar alcohols as well as other compounds derived from pentose-phosphate pathway from readily available substrates such a hexoses using metabolically engineered microbial hosts.
摘要:
A fungal microorganism can be engineered by means of genetic engineering to utilise L-arabinose. The genes of the L-arabinose pathway, which were unknown, i.e. L-arabinitol 4-dehydrogenase and L-xylulose reductase, were identified. These genes, together with the known genes of the L-arabinose pathway, form a functional pathway. This pathway can be introduced to a fungus, which is completely or partially lacking this pathway.
摘要:
The present invention relates to fungal microorganism having an increased ability to carry out biotechnological process(es). In particular, the invention relates to improving the regeneration of redox cofactors in biotechnological processes where useful products are produced from biomass containing pentoses. According to the invention, the microorganism is transformed with a DNA sequence encoding an NADP linked glyceraldehyde 3-phosphate dehydrogenase. The invention can be used to provide useful products for mankind from biological materials, including e.g. agricultural and forestry products, municipal waste. Examples of such useful products are ethanol, lactic acid, polyhydroxyalkanoates, amino acids, fats, vitamins, nucleotides and a wide variety of enzymes and pharmaceuticals.
摘要:
The present invention relates to a method and microbial host strain for converting a hexuronic acid to a hexaric acid. In particular, the invention relates to the con-version of D-galacturonic acid to meso-galactaric acid (mucic acid). The invention also concerns an isolated nucleotide sequence. According to the present method a microbial host strain genetically modified to express uronate dehydrogenase enzyme (EC 1.1.1.203) is contacted with a biomaterial comprising hexuronic acid and the con-version products are recovered. By using the recombinant microorganisms of the present invention it is possible to treat biomaterials comprising hexuronic acids and thereby decrease the amount of hexuronic acids released to the environment.
摘要:
A fungal microorganism can be engineered by means of genetic engineering to utilise L-arabinose. The genes of the L-arabinose pathway, which were unknown, i.e. L-arabinitol 4-dehydrogenase and L-xylulose reductase, were identified. These genes, together with the known genes of the L-arabinose pathway, form a functional pathway. This pathway can be introduced to a fungus, which is completely or partially lacking this pathway.
摘要:
The invention is directed to an isolated DNA molecule which includes a gene encoding an enzyme protein which has an NADH dependent L-xylulose reductase activity. The DNA sequence encoding the enzyme protein was identified. The invention is further directed to a microorganism transformed with said DNA molecule of the invention, as well as to the NADH dependent L-xylulose reductase. The invention can be utilised for the conversion of biomaterial, e.g. industrial waste material, containing carbohydrates to useful end products