Low‐temperature synthesis of 2′‐deoxyadenosine using immobilized psychrotrophic microorganisms

Fernández‐Lucas, Jesús; Condezo, L.A.; Quezada, Michelle; Sinisterra, J. V.

doi:10.1002/bit.21756

Cited by 14 publications

(10 citation statements)

References 32 publications

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“…In Figure 2 we show that an excess in dUrd dramatically increases the productivity values. Similar results have been described [ 5 , 9 , 16 , 18 , 19 ], suggesting that the rate controlling step is the first one ( Scheme 3 ). The excess of adenine moderately increases the yield.…”

Section: Resultssupporting

confidence: 88%

Thermus thermophilus Strains Active in Purine Nucleoside Synthesis

Almendros¹,

Gago²,

Carlos

2009

Molecules

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Several strains of Thermus thermophilus were tested in order to detect purine nucleoside synthase activity using pyrimidine nucleosides as the sugar-donor and adenine or hypoxanthine as bases. High productivity values (t =1 hr) were obtained while completely avoiding adenosine-deaminase degradation of the products. N-2-deoxy-ribosyltransferase activity is described for the first time in hyperthermophilic bacteria.

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Section: Resultssupporting

confidence: 88%

Thermus thermophilus Strains Active in Purine Nucleoside Synthesis

Almendros¹,

Gago²,

Carlos

2009

Molecules

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“…Good yields were obtained with agar, κ -carrageenan and alginate matrices (Table 1). In order to allow comparison of catalyst effectiveness both in terms of productivity per mass of cells and productivity per mass of catalyst, two separate specific activities were calculated for each catalyst, with respect to dry weight (dw) of cells and wet weight (ww) of catalyst as follows [17]:…”

Section: Resultsmentioning

confidence: 99%

“…A dimensional parameter known as Thiele modulus ( ϕ ) can also be used to indicate the effect of mass transfer resistance on the overall reaction rate [17]. For a first order reaction and spherical biocatalyst, the Thiele modulus ( ϕ ) can be calculated according to Equation (6):…”

Section: Resultsmentioning

confidence: 99%

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Immobilization of Acetobacter sp. CCTCC M209061 for efficient asymmetric reduction of ketones and biocatalyst recycling

et al. 2012

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BackgroundThe bacterium Acetobacter sp. CCTCC M209061 is a promising whole-cell biocatalyst with exclusive anti-Prelog stereoselectivity for the reduction of prochiral ketones that can be used to make valuable chiral alcohols such as (R)-4-(trimethylsilyl)-3-butyn-2-ol. Although it has promising catalytic properties, its stability and reusability are relatively poor compared to other biocatalysts. Hence, we explored various materials for immobilizing the active cells, in order to improve the operational stability of biocatalyst.ResultsIt was found that Ca-alginate give the best immobilized biocatalyst, which was then coated with chitosan to further improve its mechanical strength and swelling-resistance properties. Conditions were optimized for formation of reusable immobilized beads which can be used for repeated batch asymmetric reduction of 4′-chloroacetophenone. The optimized immobilized biocatalyst was very promising, with a specific activity of 85% that of the free-cell biocatalyst (34.66 μmol/min/g dw of cells for immobilized catalyst vs 40.54 μmol/min/g for free cells in the asymmetric reduction of 4′-chloroacetophenone). The immobilized cells showed better thermal stability, pH stability, solvent tolerance and storability compared with free cells. After 25 cycles reaction, the immobilized beads still retained >50% catalytic activity, which was 3.5 times higher than degree of retention of activity by free cells reused in a similar way. The cells could be recultured in the beads to regain full activity and perform a further 25 cycles of the reduction reaction. The external mass transfer resistances were negligible as deduced from Damkohler modulus Da < <1, and internal mass transfer restriction affected the reduction action but was not the principal rate-controlling step according to effectiveness factors η < 1 and Thiele modulus 0.3<∅ <1.ConclusionsCa-alginate coated with chitosan is a highly effective material for immobilization of Acetobacter sp. CCTCC M209061 cells for repeated use in the asymmetric reduction of ketones. Only a small cost in terms of the slightly lower catalytic activity compared to free cells could give highly practicable immobilized biocatalyst.

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“…The main microbial source of NDTs for nucleoside enzymatic synthesis comes from different species of Lactobacillus , such as L. helveticus [7], L. leichmannii , L. fermentum [8], and L. reuteri [9]. In addition, extremophiles have also shown the presence of NDTs with applicability in nucleoside synthesis [10,11]. In this sense, cold-adapted microbial enzymes are described to be more productive at low temperatures than their mesophilic or thermophilic counterparts [12].…”

Section: Introductionmentioning

confidence: 99%

Nucleoside 2'-Deoxyribosyltransferase from Psychrophilic Bacterium Bacillus psychrosaccharolyticus — Preparation of an Immobilized Biocatalyst for the Enzymatic Synthesis of Therapeutic Nucleosides

et al. 2014

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Nucleoside 2'-deoxyribosyltransferase (NDT) from the psychrophilic bacterium Bacillus psychrosaccharolyticus CECT 4074 has been cloned and produced for the first time. A preliminary characterization of the recombinant protein indicates that the enzyme is an NDT type II since it catalyzes the transfer of 2'-deoxyribose between purines and pyrimidines. The enzyme (BpNDT) displays a high activity and stability in a broad range of pH and temperature. In addition, different approaches for the immobilization of BpNDT onto several supports have been studied in order to prepare a suitable biocatalyst for the one-step industrial enzymatic synthesis of different therapeutic nucleosides. Best results were obtained by adsorbing the enzyme on PEI-functionalized agarose and subsequent cross-linking with aldehyde-dextran (20 kDa and 70% oxidation degree). The immobilized OPEN ACCESSMolecules 2014, 19 11232 enzyme could be recycled for at least 30 consecutive cycles in the synthesis of 2'-deoxyadenosine from 2'-deoxyuridine and adenine at 37 °C and pH 8.0, with a 25% loss of activity. High conversion yield of trifluridine (64.4%) was achieved in 2 h when 20 mM of 2'-deoxyuridine and 10 mM 5-trifluorothymine were employed in the transglycosylation reaction catalyzed by immobilized BpNDT at 37 °C and pH 7.5.

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Low‐temperature synthesis of 2′‐deoxyadenosine using immobilized psychrotrophic microorganisms

Cited by 14 publications

References 32 publications

Thermus thermophilus Strains Active in Purine Nucleoside Synthesis

Thermus thermophilus Strains Active in Purine Nucleoside Synthesis

Immobilization of Acetobacter sp. CCTCC M209061 for efficient asymmetric reduction of ketones and biocatalyst recycling

Nucleoside 2'-Deoxyribosyltransferase from Psychrophilic Bacterium Bacillus psychrosaccharolyticus — Preparation of an Immobilized Biocatalyst for the Enzymatic Synthesis of Therapeutic Nucleosides

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