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EP-4739784-A1 - METHOD FOR PRODUCING AN AQUEOUS SOLUTION CONTAINING ETHYLENE GLYCOL

EP4739784A1EP 4739784 A1EP4739784 A1EP 4739784A1EP-4739784-A1

Abstract

A method for producing an aqueous solution containing ethylene glycol and/or a salt of pyruvic acid, by treating 2-keto-3-deoxy-D-xylonate (KDX) and/or 2-keto-3-deoxy-L-arabonate (KDA) in vitro with an aldolase (EC 4.1.2.55) to give an aqueous solution which contains glycol aldehyde and a salt of pyruvic acid, after which the glycol aldehyde is reduced using an NAD(P)H-dependent alcohol dehydrogenase (EC 1.1.1.1) or an NAD(P)H-dependent xylose reductase (EC 1.1.1.307) and subsequently optionally removing either the salt of pyruvic acid or the ethylene glycol from the solution.

Inventors

  • STAUNIG, Nicole
  • Frühwirt, Philipp

Assignees

  • Annikki GmbH

Dates

Publication Date
20260513
Application Date
20240708

Claims (8)

  1. 1. Process for the preparation of an aqueous solution containing ethylene glycol and a salt of pyruvic acid by treating 2-keto-3-deoxy-D-xylonate (KDX) and/or 2-keto-3-deoxy-L-arabonate (KDA) in vitro with an aldolase, whereby an aqueous solution is obtained which contains glycolaldehyde and a salt of pyruvic acid, after which the glycolaldehyde is reduced to ethylene glycol by treatment with an NAD(P)H-dependent alcohol dehydrogenase or with an NAD(P)H-dependent xylose reductase in vitro, wherein the oxidized cofactor NAD(P) + formed by the reduction with the alcohol dehydrogenase or together with the xylose reductase is reduced by means of a secondary alcohol to form a ketone and then, if appropriate, either the salt of pyruvic acid or the ethylene glycol is removed from the solution.
  2. 2. Process for the preparation of an aqueous solution containing ethylene glycol and a salt of lactic acid by treating 2-keto-3-deoxy-D-xylonate (KDX) and/or 2-keto-3-deoxy-L-arabonate (KDA) in vitro with an aldolase, whereby an aqueous solution is obtained which contains glycolaldehyde and a salt of pyruvic acid, after which the glycolaldehyde is reduced in vitro by treatment with an NAD(P)H-dependent alcohol dehydrogenase or with an NAD(P)H-dependent xylose reductase to ethylene glycol and the salt of pyruvic acid is reduced in vitro by means of a lactate dehydrogenase to a salt of lactic acid, wherein the oxidized cofactor NAD(P) + formed by the reduction with the alcohol dehydrogenase or together with the xylose reductase is reduced by means of a secondary alcohol to form a ketone and then optionally either the lactic acid salt or the ethylene glycol is removed from the solution.
  3. 3. Process for the preparation of an aqueous solution containing ethylene glycol, in which glycolaldehyde, which is dissolved in an aqueous solution, is reduced to ethylene glycol by treatment with an NAD(P)H-dependent alcohol dehydrogenase or together with an NAD(P)H-dependent xylose reductase in vitro and the oxidized cofactor NAD(P) + formed by the reduction is reduced by means of a secondary alcohol to form a ketone.
  4. 4. Process according to one of claims 1 to 3, characterized in that the secondary alcohol is 2-propanol.
  5. 5. Method according to one of claims 1 to 4, characterized in that the enzymes are present as a lysate of the corresponding cells producing them.
  6. 6. The method according to any one of claims 1 to 5, characterized in that the NAD(P)H-dependent alcohol dehydrogenase for reducing glycolaldehyde to ethylene glycol comprises an amino acid sequence selected from the group consisting of: i) an amino acid sequence having an identity to SEQ ID No. 1, 3 or 5 of at least 80%, ii) an amino acid sequence encoded by a nucleic acid having an identity to SEQ ID No. 2, 4 or 6 of at least 80%, and iii) an amino acid sequence encoded by a nucleic acid that binds under stringent conditions to a complementary strand of a nucleic acid molecule having the nucleic acid sequence SEQ ID No. 2, 4 or 6.
  7. 7. The method according to any one of claims 1 to 6, characterized in that the NAD(P)H-dependent xylose reductase for reducing glycolaldehyde to ethylene glycol comprises an amino acid sequence selected from the group consisting of: i) an amino acid sequence having an identity to SEQ ID No. 7 of at least 80%, ii) an amino acid sequence encoded by a nucleic acid having an identity to SEQ ID No. 8 of at least 80%, and iii) an amino acid sequence encoded by a nucleic acid that binds under stringent conditions to a complementary strand of a nucleic acid molecule having the nucleic acid sequence SEQ ID No. 8.
  8. 8. Use of a NAD(P)H-dependent alcohol dehydrogenase and/or a NAD(P)H-dependent xylose reductase for the reduction of glycolaldehyde to ethylene glycol, wherein the NAD(P)H-dependent alcohol dehydrogenase preferably comprises an amino acid sequence which is selected from the group consisting of: i) an amino acid sequence which has an identity to SEQ ID No. 1, 3 or 5 of at least 80%, ii) an amino acid sequence which is encoded by a nucleic acid which has an identity to SEQ ID No. 2, 4 or 6 of at least 80%, and iii) an amino acid sequence encoded by a nucleic acid that binds under stringent conditions to a complementary strand of a nucleic acid molecule having the nucleic acid sequence SEQ ID No. 2, 4 or 6, and the NAD(P)H-dependent xylose reductase preferably comprises an amino acid sequence selected from the group consisting of: i) an amino acid sequence having an identity to SEQ ID No. 7 of at least 80%, ii) an amino acid sequence encoded by a nucleic acid that has an identity to SEQ ID No. 8 of at least 80%, and iii) an amino acid sequence encoded by a nucleic acid that binds under stringent conditions to a complementary strand of a nucleic acid molecule having the nucleic acid sequence SEQ ID No. 8

Description

Process for preparing an aqueous solution containing ethylene glycol The invention relates to a process for producing an aqueous solution which contains ethylene glycol and a salt of pyruvic acid (pyruvate) or ethylene glycol and a salt of lactic acid (lactate). Background of the invention Ethylene glycol (ethane-l,2-diol), the simplest dihydric alcohol, is an important industrial chemical - it is used, for example, as an antifreeze or as a precursor for the polymers polyethylene terephthalate (PET) and polyethylene furanoate (PEF), a bio-based alternative to PET (Salusjärvi et al., 2019). Ethylene glycol is produced by the hydrolysis of ethylene oxide (at 200 °C), which in turn is obtained by the oxidation of ethylene (obtained from fossil raw materials). The resulting by-products (oligoethylene glycols) must be separated by distillation, which is energy-intensive. To avoid by-products, for example, Shell's OMEGA process (Only Mono Ethylene Glycol Advantage) can be used, in which ethylene oxide is first reacted with CO2 to form ethylene carbonate, which is then hydrolyzed to ethylene glycol with the release of CO2 (with Kl and K2MOO4 as catalysts). Other processes are the Rh- or Co-catalyzed hydrohydroxymethylation of formaldehyde or the hydroformylation of formaldehyde to glycolaldehyde, which is then reduced to ethylene glycol (Berger, 2016). Since the current large-scale processes cannot be described as sustainable due to the high energy consumption (high temperatures) as well as the fossil origin of the raw materials (ethylene) or the use of expensive, sometimes toxic catalysts, biotechnological processes are being and have been developed that are based on renewable raw materials and are carried out under milder reaction conditions. In order to develop sustainable production processes for chemicals from biomass, less energy-intensive methods are needed that make use of the existing diversity of the biomaterial. In addition to efficient, gentle methods for depolymerizing renewable raw materials into shorter-chain sugars, efficient technologies are needed to further convert these carbohydrate intermediates into chemical products. A particular challenge is to efficiently and as completely as possible convert the mixtures of substances resulting from depolymerization into valuable material streams. In general, straws, wood and other plant-based raw materials contain hemicelluloses and celluloses, from which monomer sugars can be released in varying compositions, primarily the pentoses D-xylose and L-arabinose, the hexoses D-glucose, D-mannose and D-galactose as well as acids derived from the sugars (e.g. D-glucuronic acid). Methods for the efficient separation of C 6 and C 5 sugars allow these material flow types to be treated separately (e.g. US 9970038 B2). In corn husks, for example, one finds, based on the total sugar, 10% L-arabinose, 16% D-xylose, 64% D-glucose, 4% D-galactose and 2% D-mannose (Hromädkovä & Ebringerovä, 1995), whereas in wheat straw it is 5% L-arabinose, 30% D-xylose, 56% D-glucose, 1% D-galactose and 2% D-mannose (Collins et al., 2014). These percentage values show that the ratios of L-arabinose and D-xylose in both biomasses differ greatly from each other (corn husks: 1:1.6 and wheat straw: 1:6). Currently, biotechnological efforts focus primarily on processes aimed at converting biomass into chemical products by means of fermentation, i.e. the conversion of substances during the growth of microbes in a reactor. Despite all the technical advances in the field, such as metabolism engineering and heterologous pathway expression, these fermentative whole-cell processes are limited by the physiological limitations of cellular production (tolerance to solvents, temperature, substance transport and to high substrate and product concentrations, but also by byproducts from other metabolic pathways in the cell) (Claassens et al., 2019). These intracellular processes and in particular the energy requirements for the metabolic (often also CC-emitting) steps lead to long process times on the one hand and to the achievable carbon yield being significantly below the theoretically possible one on the other. In addition, these processes generally use biosynthetic metabolic pathways that release CO2 from the substrate, so that even the theoretical carbon yield in the product is only a fraction of the carbon used: While 1 - 4 carbons are lost for Cg sugars, depending on the metabolic pathway, 1 - 3 are lost for C5 sugars. Typical key data of such processes are summarized in the literature (Salusjärvi et al., 2019). Alkim et al. describe a process for producing ethylene glycol from D-xylose via a synthetic metabolic pathway in Escherichia coli. D-xylose is first isomerized to D-xylulose using D-xylose isomerase, which is then phosphorylated to D-xylulose-l-phosphate using adenosine triphosphate (ATP) using D-xylulose-l-kinase. The aldol cleavage catalyzed by D-xylulose-1-phosphate aldolase yields di