The present invention discloses a transaminase mutant and application thereof in preparation of sitagliptin intermediates, the transaminase mutant is obtained by substitution of tyrosine with proline at position 74, substitution of glutamic acid with aspartic acid at position 228, substitution of leucine with alanine at position 254 and substitution of methionine with threonine at position 290 of the amino acid sequence shown in SEQ ID NO: 2. The present invention uses wet cells or a purified transaminase as a biocatalyst and a sitagliptin precursor ketone or a prochiral carbonyl compound as a substrate to prepare a sitagliptin intermediate or a sitagliptin ester intermediate; the total yield of the method reaches about 82%, and e.e. value of the product reaches 99%.

Provided are a novel tricyclic dilactone compound, a strain producing the same, a method of producing the tricyclic dilactone compound, and use of the tricyclic dilactone compound. The tricyclic dilactone compound has activity of inhibiting aggregation of amyloid-beta and tau proteins, activity of inhibiting apoptosis, and anti-inflammation activity, and thus may be used to prevent, treat, or improve various neurodegenerative brain diseases including Alzheimer's disease and cognitive impairment.

The present invention provides for a polyketide synthase (PKS) capable of synthesizing an even-chain or odd-chain diacid or lactam or diamine. The present invention also provides for a host cell comprising the PKS and when cultured produces the even-chain diacid, odd-chain diacid, or KAPA. The present invention also provides for a host cell comprising the PKS capable of synthesizing a pimelic acid or KAPA, and when cultured produces biotin.

A method for improving the production of Streptomyces polyketide compounds is provided. The method greatly improves the capability of the Streptomyces polyketide compounds by strengthening a triacylglycerol decomposition pathway in Streptomyces during the stationary phase. A method for switching the primary metabolism of Streptomyces to the secondary metabolism, Streptomyces producing polyketide compounds, and use thereof are also provided.

A method for improving the production of Streptomyces polyketide compounds is provided. The method greatly improves the capability of the Streptomyces polyketide compounds by strengthening a triacylglycerol decomposition pathway in Streptomyces during the stationary phase. A method for switching the primary metabolism of Streptomyces to the secondary metabolism, Streptomyces producing polyketide compounds, and use thereof are also provided.

Disclosed is a method for the manufacture of a spray-dried powder consisting essentially of 3-fucosyllactose, the spray-dried powder, its use for the manufacture of nutritional compositions, and nutritional compositions containing the spray-dried powder.

The present application relates to recombinant microorganisms useful in the biosynthesis of monoethylene glycol (MEG) or glycolic acid (GA), or MEG and one or more co-product, from one or more pentose and/or hexose sugars. Also provided are methods of producing MEG (or GA), or MEG (or GA) and one or more co-product, from one or more pentose and/or hexose sugars using the recombinant microorganisms, as well as compositions comprising the recombinant microorganisms and/or the products MEG (or GA), or MEG and one or more co-product.

The present application relates to recombinant microorganisms useful in the biosynthesis of monoethylene glycol (MEG) or glycolic acid (GA), or MEG and one or more co-product, from one or more pentose and/or hexose sugars. Also provided are methods of producing MEG (or GA), or MEG (or GA) and one or more co-product, from one or more pentose and/or hexose sugars using the recombinant microorganisms, as well as compositions comprising the recombinant microorganisms and/or the products MEG (or GA), or MEG and one or more co-product.

The invention generally relates to methods of producing loline alkaloids or precursors thereof, expression constructs, and host cells useful for producing loline alkaloids or precursors thereof, and methods for producing loline alkaloids or precursors thereof in a host cell.

Provided is use of immobilized transaminase in preparation of sitagliptin and/or (R)-3-amino-1-morpholine-4-(2,4,5-trifluorophenyl)-1-butanone. The immobilized transaminase comprises resin and a transaminase mutant, the amino acid sequence of the transaminase mutant is as shown in SEQ ID NO: 3 or SEQ ID NO: 7. Also provided is an immobilized transaminase, a transaminase mutant, a preparation method therefor and use thereof. The enzyme activity of the transaminase mutant in the catalysis of a ketoamide substrate is high, and the enzyme activity is still high after the transaminase mutant is prepared into the immobilized transaminase. When the transaminase mutant is used for catalyzing the ketoamide substrate to produce sitagliptin or an intermediate thereof, a screened solvent reaction system is combined, the immobilized transaminase is high in conversion rate and good in stereoselectivity and stability, the repeatability rate is improved, and the operation is simpler, thereby reducing the cost of production, and it is beneficial to industrial production.