The present disclosure describes the engineering of microbial cells for fermentative production of tyramine and provides novel engineered microbial cells and cultures, as well as related tyramine production methods.

The invention concerns a genetically modified microorganism expressing a functional type I or II RuBisCO enzyme and a functional phosphoribulokinase (PRK), and in which the non-oxidative branch of the pentose phosphate pathway is at least partially inhibited, said microorganism being genetically modified so as to produce an exogenous molecule and/or to overproduce an endogenous molecule. The invention also concerns the use of such a genetically modified microorganism for the production or overproduction of a molecule of interest and processes for the synthesis or bioconversion of molecules of interest.

The present invention provides for a mechanism to completely replace the electron accepting function of glycerol formation with an alternative pathway to ethanol formation, thereby reducing glycerol production and increasing ethanol production. In some embodiments, the invention provides for a recombinant microorganism comprising a down-regulation in one or more native enzymes in the glycerol-production pathway. In some embodiments, the invention provides for a recombinant microorganism comprising an up-regulation in one or more enzymes in the ethanol-production pathway.

The invention relates to a cell capable of converting one or more pentose sugar and one or more hexose sugar into fermentation product constitutively expressing one or more heterologous or homologous polypeptide having the amino acid sequence set out in SEQ ID NO: 20, or a variant polypeptide thereof having at least 45% identity to SEQ ID NO 20. In an embodiment the heterologous polypeptide has glyoxalase activity.

This invention is aimed at improving an ethanol fermentation ability of a recombinant yeast strain having an ability of assimilating pentose, such as xylose or arabinose. The recombinant yeast strain haying an ability of assimilating pentose is obtained by lowering activity of a gene involved in upstream of glyceraldehyde-3-phosphate in the Embden-Meyerhof pathway.

An engineered yeast strain capable of efficient fermentation of xylose to ethanol, and methods of making and using the strain, are provided.

An acetic acid metabolizing ability of a recombinant yeast strain having xylose-metabolizing ability is to be improved. In such a recombinant yeast strain having xylose-metabolizing ability, the acetaldehyde dehydrogenase gene has been introduced and a gene encoding NADH dehydrogenase involved in reoxidation of cytoplasmic NADH on the mitochondrial outer membrane has been suppressed.

An object of the present invention is to obtain a fermentative yeast having a highly efficient ethanol production without introducing a foreign gene. A further object is to obtain a fermentative yeast that is resistant to proliferation inhibitors such as organic acids, which prevent the proliferation of the fermentative yeast. A yeast having an improved ethanol production ability was generated by introducing transaldolase and alcohol dehydrogenase genes by self-cloning to Meyerozyma guilliermondii that can produce ethanol effectively from pentose and hexose obtained by breeding, and further breeding the resultant yeast.

An object of the present invention is to obtain a fermentative yeast having a highly efficient ethanol production without introducing a foreign gene. A further object is to obtain a fermentative yeast that is resistant to proliferation inhibitors such as organic acids, which prevent the growth of the fermentative yeast. Yeast having improved ethanol production ability was generated by introducing transaldolase and alcohol dehydrogenase gene by self-cloning to Meyerozyma guilliermondii that can produce ethanol effectively from pentose and hexose obtained by breeding. This fermentative yeast is deposited to NITE Patent Microorganisms Depositary under the accession number NITE ABP-01976.

Processes for producing ethanol comprise saccharifying cellulosic material with a cellulolytic enzyme composition and fermenting the saccharified cellulosic material with a fermenting microorganism to produce ethanol. The fermenting organism is Saccharomyces cerevisiae CIBTS1260 (deposited under Accession No. NRRL Y-50973 at the Agricultural Research Service Culture Collection (NRRL), Illinois 61604 U.S.A.) or a fermenting organism that has properties that the same or about the same as that of Saccharomyces cerevisiae CIBTS1260).