One-pot, two-step transaminase and transketolase synthesis of l-gluco-heptulose from l-arabinose

Abstract

The use of biocatalysis for the synthesis of high value added chemical building blocks derived from biomass is becoming an increasingly important application for future sustainable technologies. The synthesis of a higher value chemical from l-arabinose, the predominant monosaccharide obtained from sugar beet pulp, is demonstrated here via a transketolase and transaminase coupled reaction. Thermostable transketolases derived from Deinococcus geothermalis and Deinococcus radiodurans catalysed the synthesis of l-gluco-heptulose from l-arabinose and β-hydroxypyruvate at elevated temperatures with high conversions. β-Hydroxypyruvate, a commercially expensive compound used in the transketolase reaction, was generated in situ from l-serine and α-ketoglutaric acid via a thermostable transaminase, also from Deinococcus geothermalis. The two steps were investigated and implemented in a one-pot system for the sustainable and efficient production of l-gluco-heptulose.

One‐Pot Cascade Synthesis of (3S)‐Hydroxyketones Catalyzed by Transketolase via Hydroxypyruvate Generated in Situ from d‐Serine by d‐Amino Acid Oxidase

“…[3] Enzymatic in situ generation of HPA has been previously described, in particular from l-serine using transaminases (TA) (Scheme 1A). [4][5][6] The reversibility of the TA-reaction requires the simultaneous coupling to an irreversible enzyme-catalyzed reaction to shift the overall equilibrium toward HPA formation and to avoid its accumulation and degradation, particularly at high temperature, and/or in buffered solution. [5] The irreversible TK-catalyzed decarboxylation of HPA is a powerful tool for such an approach.…”

“…[1] The coupling of the TA and the TK reactions in a one pot has been developed producing the expected ketose products. [4][5][6] The major drawback of this approach is the requirement of an α-keto acid as an amino group acceptor, which is a second substrate generating the corresponding amino acid as an additional by-product if not recycled. In addition, the equilibrium shift toward the formation of the product needs an excess of one of the two TA substrates, i. e., d-serine or α-keto acid, and in the latter case inhibition of TA was observed.…”

“…In addition, the equilibrium shift toward the formation of the product needs an excess of one of the two TA substrates, i. e., d-serine or α-keto acid, and in the latter case inhibition of TA was observed. [5,6] To circumvent all these limitations, another strategy consists in using an aminoacid oxidase (AAO) to catalyze the oxidative deamination of serine into HPA (Scheme 1B). Substrate specificity studies of AAOs have shown that the best substrates for lAAOs are hydrophobic aminoacids [7] while dAAOs display a broad aminoacid spectrum including d-serine.…”

Data on a thermostable enzymatic one-pot reaction for the production of a high-value compound from l-arabinose

“…l -Arabinose is a major monosaccharide of sugar beet pulp (SBP), a by-product of sucrose extraction which is currently produced and sold as a low value animal feed [1] . The main focus of this work was to create a value-added product from the monosaccharides that make up SBP via enzymatic routes.…”

Aminopolyols from Carbohydrates: Amination of Sugars and Sugar‐Derived Tetrahydrofurans with Transaminases

“…Thel atter was efficiently prepared by ao ne-step reaction catalyzed by amutant transketolase enzyme starting from larabinose. [36,37] Quantification of the TAmreactions was carried out using MBAa nd acetophenone detection by HPLC.T his method indicated conversion yields of up 54 %for d-ribose,29% for d-GalAc and l-sorbose,2 8% for d-xylose,a nd about 23 % for d-tagatose and l-glucoheptulose.N otably, Mv-TAm showed ac onversion yield of 40 %w ith d-fructose at 45 8 8C when (R)-MBAwas used as the amine donor.G enerally,the ketosugars were well accepted by Mv-TAm and the TAm encoded by pQR2191, although l-glucoheptulose was only accepted by pQR2191. Use of the cosolvent DMSO also seemed to be less relevant when aketo sugar was used as the substrate as high conversions could still be obtained in its absence.T he acceptance of d-GalAc (Figure 4) was interesting as this produces an w-aminoacid with potential as am onomer for the preparation of polyhydroxy polyamides as analogues of Nylon-6.…”