The invention provides a method of producing a chemical product through continuous fermentation which includes filtering a culture of a microorganism or cultured cells with a separation membrane to recover a product from a filtrate and simultaneously retaining a nonfiltered fluid in, or refluxing it to, the culture, and adding fermentation materials to the culture, wherein a porous membrane having an average pore size of 0.01 m or more to less than 1 m is used as the separation membrane and the filtration is conducted with a transmembrane pressure difference in the range of 0.1 to 20 kPa. According to this method, the fermentation productivity of the chemical product can be largely elevated at high stability and a low cost.

A method of producing a chemical product by continuous fermentation utilizes a separation membrane under conditions at a pH of not more than 3.5, wherein yeast having vanillin resistance is used to enable efficient production of a chemical product without leaving a large amount of fermentation feedstock unused, is provided.

Methods and processes for producing aerobic digestion products, such as organic acids, from a low-rank coal substrate are provided. Also provided are multistage bioreactor systems for carrying out the described methods and processes. In another aspect, product compositions comprising organic acids produced by the described methods and processes are provided, as well as methods for their use, including for the improvement of soil quality and/or plant growth.

Methods and processes for producing aerobic digestion products, such as organic acids, from a low-rank coal substrate are provided. Also provided are multistage bioreactor systems for carrying out the described methods and processes. In another aspect, product compositions comprising organic acids produced by the described methods and processes are provided, as well as methods for their use, including for the improvement of soil quality and/or plant growth.

In a method for preparing a keto acid, an enzymatic reaction is carried out by using glycine and an alcoholic organic substance as substrates; the alcoholic organic substance is converted into an aldehyde organic substance, glycine and the aldehyde organic substance are converted into a -hydroxy--amino acid, and then the -hydroxy--amino acid is converted into a keto acid. The preparation method for a keto acid can also be used in the preparation of amino acids. The number of enzymes used is much less than that of enzymes used in a natural synthesis route, so that the production cost is low. An artificial metabolism platform for keto acids is established and can produce multiple important keto acids, such as phenylpyruvic acid, 4-methyl-2-oxopentanoic acid, pyruvic acid and 2-oxo-butyric acid.

In a method for preparing a keto acid, an enzymatic reaction is carried out by using glycine and an alcoholic organic substance as substrates; the alcoholic organic substance is converted into an aldehyde organic substance, glycine and the aldehyde organic substance are converted into a -hydroxy--amino acid, and then the -hydroxy--amino acid is converted into a keto acid. The preparation method for a keto acid can also be used in the preparation of amino acids. The number of enzymes used is much less than that of enzymes used in a natural synthesis route, so that the production cost is low. An artificial metabolism platform for keto acids is established and can produce multiple important keto acids, such as phenylpyruvic acid, 4-methyl-2-oxopentanoic acid, pyruvic acid and 2-oxo-butyric acid.

The present invention relates to processes for the formation of pyridinedicarboxylic acid (PDCA), in particular, 2,4-pyridinedicarboxylic acid (2,4-PDCA) and 2,5-pyridinedicarboxylic acid (2,5-PDCA), and mono- and diester derivatives thereof, from 3,4-dihydroxybenzoic acid, via a biocatalytic reaction using, for example, a protocatechuate dioxygenase such as protocatechuate 4,5-dioxygenase or protocatechuate 2,3-dioxygenase, and a nitrogen source. The invention also relates to copolymers that comprise the pyridinedicarboxylic acid monomers and derivatives thereof, processes for the formation of the copolymers and uses for the copolymers.

The present invention relates to processes for the formation of pyridinedicarboxylic acid (PDCA), in particular, 2,4-pyridinedicarboxylic acid (2,4-PDCA) and 2,5-pyridinedicarboxylic acid (2,5-PDCA), and mono- and diester derivatives thereof, from 3,4-dihydroxybenzoic acid, via a biocatalytic reaction using, for example, a protocatechuate dioxygenase such as protocatechuate 4,5-dioxygenase or protocatechuate 2,3-dioxygenase, and a nitrogen source. The invention also relates to copolymers that comprise the pyridinedicarboxylic acid monomers and derivatives thereof, processes for the formation of the copolymers and uses for the copolymers.

Methods and processes for producing aerobic digestion products, such as organic acids, from a low-rank coal substrate are provided. Also provided are multistage bioreactor systems for carrying out the described methods and processes. In another aspect, product compositions comprising organic acids produced by the described methods and processes are provided, as well as methods for their use, including for the improvement of soil quality and/or plant growth.

Methods and processes for producing aerobic digestion products, such as organic acids, from a low-rank coal substrate are provided. Also provided are multistage bioreactor systems for carrying out the described methods and processes. In another aspect, product compositions comprising organic acids produced by the described methods and processes are provided, as well as methods for their use, including for the improvement of soil quality and/or plant growth.