Acetate is a potent microbial inhibitor which can affect the performance of yeast in ethanolic fermentation. The present disclosure provides a recombinant microbial host cell having (i) a first genetic modification for increasing the activity of one or more proteins that function in a first metabolic pathway to convert acetate into an alcohol in the microbial host cell; (ii) a second genetic modification for increasing the activity of one or more proteins that function in a second metabolic pathway to import glycerol in the recombinant microbial host cell (iii) a third genetic modification for increasing the activity of one or more proteins that function in a third metabolic pathway to convert a C5 carbohydrate into ethanol in the microbial host cell. The recombinant microbial host cell comprises and natively expresses native proteins that function in a fourth native metabolic pathway to produce glycerol in the microbial host cell.

A method and cell line for producing phytocannabinoids and phytocannabinoid analogues in yeast. The method applies, and the cell line includes, a yeast cell transformed with a polyketide synthase CDS and a cytosolic prenyltransferase CDS. The polyketide synthase enzyme catalyzes synthesis of olivetol or methyl-olivetol, and may include Cannabis sativa olivetolic acid synthase or Dictyostelium discoideum polyketide synthase (“DiPKS”). The yeast cell may be modified to include a phosphopantethienyl transferase for increased activity of DiPKS. The yeast cell may be modified to mitigate mitochondrial acetaldehyde catabolism for increasing malonyl-CoA available for synthesizing olivetol or methyl-olivetol. The prenyltransferase enzyme catalyzes synthesis of cannabigerol or a cannabigerol analogue, and may include an αββα cytosolic prenyltransferase enzyme from Streptomyces sp CL190. The yeast cell may be modified to mitigate depletion of geranyl pyrophosphate for increasing available geranyl pyrophosphate for prenylation.

The present invention relates to methods of upgrading biomass to provide useful chemical intermediates, fuels, amino acids, nutrients, etc. In particular examples, the biomass is a by-product of ethanol production and is mainly used as high-protein feed. Described herein are methods for upgrading such biomass, such as by implementing pre-treatment conditions and by employing fermentation conditions including modified organisms.

A starch biosynthesis method may implement total artificial biosynthesis from simple compounds such as dihydroxyacetone, formaldehyde, formic acid and methanol to starch. By coupling with methods such as chemical reduction of carbon dioxide, even total artificial biosynthesis of starch taking carbon dioxide as a starting raw material can be implemented. The method can utilize carbon dioxide of high concentration and high density and electric energy and hydrogen energy of high energy density, is more suitable for an industrial production mode, and the production cycle is shortened from several months in farming to several days.

Methods for producing acetaldehyde from ethanol are provided. In embodiments, such a method comprises (a) exposing ethanol and furfural to a biocatalyst comprising yeast alcohol dehydrogenase 1, yeast alcohol dehydrogenase 2, and yeast alcohol dehydrogenase 3, and a biocatalyst cofactor under conditions that oxidize the ethanol to acetaldehyde and reduce the furfural to furfuryl alcohol to provide a product mixture comprising the acetaldehyde and the furfuryl alcohol; and (b) recovering the acetaldehyde from the product mixture as it is being produced in step (a).

The invention discloses an alcohol dehydrogenase mutant and use thereof. The alcohol dehydrogenase mutant of the present invention has high thermal stability and enables high catalytic efficiency and high conversion rate (i.e. space time yield) in the asymmetric reduction of prochiral diaryl ketones to produce chiral diaryl alcohols. Therefore, the alcohol dehydrogenase mutant of the present invention has extremely high prospect of application in the production of chiral diaryl alcohols, such as (S)-(4-chlorophenyl)-(pyridin-2-yl)-methanol, (R)-(4-chlorophenyl)-(pyridin-2-yl)-methanol.

The present invention relates to a yeast cell, in particular a recombinant yeast cell, the cell lacking enzymatic activity needed for the NADH-dependent glycerol synthesis or the cell having a reduced enzymatic activity with respect to the NADH-dependent glycerol synthesis compared to its corresponding wild-type yeast cell, the cell comprising one or more heterologous nucleic acid sequences encoding an NAD.sup.+-dependent acetylating acetaldehyde dehydrogenase (EC 1.2.1.10) activity. The invention further relates to the use of a cell according to the invention in the preparation of ethanol.

There is provided an acetogenic microbial cell which is capable of producing at least one higher alcohol from a carbon source, wherein the acetogenic microbial cell is genetically modified to comprise an increased expression relative to its wild type cell of at least one enzyme, E.sub.8, a butyryl-CoA:acetate CoA transferase (cat3). There is also provided a method and use of the cell to produce higher alcohols.

The disclosure discloses construction and application of an engineered strain of E. coli for producing malic acid by fixing CO.sub.2, and belongs to the field of fermentation. The engineered strain is obtained by performing genetic engineering transformation on Escherichia coli MG1655; the genetic engineering transformation includes knocking out a fumarate reductase gene, a fumarase gene, a lactate dehydrogenase gene and an alcohol dehydrogenase gene and freely overexpressing a formate dehydrogenase, an acetyl coenzyme A synthetase, an acylated acetaldehyde dehydrogenase, a formaldehyde lyase, a dihydroxyacetone kinase, a malic enzyme and a phosphite oxidoreductase to obtain a strain GH0407. The strain is used for producing malic acid by fermentation, anaerobic fermentation is performed for 72 hours with CO.sub.2 and glucose as a co-substrate, the production of malic acid reaches 39 g/L, the yield is 1.53 mol/mol, and accumulation of malic acid in the original strain is not achieved.

The present invention relates to a yeast cell, in particular a recombinant yeast cell, the cell lacking enzymatic activity needed for the NADH-dependent glycerol synthesis or the cell having a reduced enzymatic activity with respect to the NADH-dependent glycerol synthesis compared to its corresponding wild-type yeast cell, the cell comprising one or more heterologous nucleic acid sequences encoding an NAD.sup.+-dependent acetylating acetaldehyde dehydrogenase (EC 1.2.1.10) activity. The invention further relates to the use of a cell according to the invention in the preparation of ethanol.