d-Tagatose production in the presence of borate by resting Lactococcus lactis cells harboring Bifidobacterium longum l-arabinose isomerase

Salonen, Noora J; Salonen, Kalle; Leisola, Matti; Nyyssölä, Antti

doi:10.1007/s00449-012-0805-2

Cited by 35 publications

(24 citation statements)

References 141 publications

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“…Boric acid has successfully been used for achieving high yields in enzymatic production of D‐psicose, D‐tagatose, L‐ribulose and lactulose (Kim et al ., , ; Zhang et al ., ; Salonen et al ., ). As shown in Fig.…”

Section: Resultsmentioning

confidence: 97%

Lactulose production from lactose by recombinant cellobiose 2‐epimerase in permeabilised Escherichia coli cells

Wang

Yang

Xiao

et al. 2015

Int J of Food Sci Tech

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Caldicellulosiruptor saccharolyticus cellobiose 2-epimerase (CsCE) catalyses the single substrate lactose into lactulose and is the most efficient enzyme ever found for the enzymatic synthesis of lactulose. Ethanol-permeabilised Escherichia coli cells containing CsCE were used as biocatalysts for lactulose production. The reaction conditions for maximum lactulose production were optimised to be 600 g L À1 lactose, pH 7.5, 80°C and 12.5 U mL À1 of whole-cell biocatalyst. After incubated at Na 2 HPO 4 -NaH 2 PO 4 buffer for 2 h, approximately 390.59 g L À1 lactulose was obtained with a conversion yield of 65.1%. The lowest production and conversion yield of epilactose were also found in Na 2 HPO 4 -NaH 2 PO 4 buffer with a final concentration of 11.7 g L À1 and a conversion yield <2%. The results represent a promising technology to attain high production and conversion yield of lactulose with a high purity on industrial scale.

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Section: Resultsmentioning

confidence: 97%

Lactulose production from lactose by recombinant cellobiose 2‐epimerase in permeabilised Escherichia coli cells

Wang

Yang

Xiao

et al. 2015

Int J of Food Sci Tech

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“…This result was strongly confirmed by a previous study that reported a positive effect of borate on the yield of conversion to D-tagatose by Bifidobacterium longum-derived L-AI. 23) Accordingly, a borate was confirmed to enhance the D-tagatose yield as well as L-ribulose production through an increase in the conversion ratio of L-AIs, including BTAI.…”

Section: )mentioning

confidence: 87%

Characterization of an L-Arabinose Isomerase from Bacillus thermoglucosidasius for D-Tagatose Production

Seo

2013

Bioscience, Biotechnology, and Biochemistry

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“…Cellular or abiotic encapsulation has shown to improve enzyme stability against thermal, pH, solvent, and impurity interactions 24,45 . In the context of tagatose production, whole cells expressing L-AI has also shown to improve conversion by preferentially partitioning substrate and product across the E. coli membrane barrier through active transport 25 ; however, the same was not observed in resting L. lactis cells 46 . Our results demonstrate that encapsulation of LAI in L. plantarum behaves in a manner similar to that in Gram-negative E. coli but not Gram-positive L. lactis .…”

Section: Discussionmentioning

confidence: 99%

“…This is the among the highest reported productivity (averaging ~ 11.4 g/L/h over 48 h) for biocatalytic tagatose production, and the highest conversion reported for a mesophilic enzyme (~85 %) 19,50 . Although further improvements to conversion may be possible by including borate in the reaction buffer, demonstrated previously, it would also increase purification costs 16,26,46 . The productivity and conversion reported here is the highest obtained for a mesophilic LAI under any conditions Further, this system nearly matches the conversion obtained in a recent study with a extremophilic LAI at 95 °C and pH 9.5 that required use of Ni 2+ and borate 51 but at 50 °C and without use of toxic metals and salts.…”

Section: Discussionmentioning

confidence: 99%

Surpassing thermodynamic, kinetic, and stability barriers to isomerization catalysis for tagatose biosynthesis

Bober

Nair

2019

Preprint

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3There are many enzymes that are relevant for making rare and valuable chemicals that 4 while active, are severely limited by thermodynamic, kinetic, or stability issues (e.g. 5 isomerases, lyases, transglycosidase etc.). In this work, we study an enzymatic reaction 6 system − Lactobacillus sakei L-arabinose isomerase (LsLAI) for D-galactose to D-tagatose 7 isomerizationthat is limited by all three reaction parameters. The enzyme has a low 8 catalytic efficiency for non-natural substrate galactose, has low thermal stability at 9 temperatures > 40 °C, and equilibrium conversion < 50%. After exploring several strategies 10 to overcome these limitations, we finally show that encapsulating the enzyme in a gram-11 positive bacterium (Lactobacillus plantarum) that is chemically permeabilized can enable 12 reactions at high rates, high conversion, and at high temperatures. The modified whole cell 13 system stabilizes the enzyme, differentially partitions substrate and product across the 14 membrane to shift the equilibrium toward product formation enables rapid transport of 15 substrate and product for fast kinetics. In a batch process, this system enables 16 approximately 50 % conversion in 4 h starting with 300 mM galactose (an average 17 productivity of 37 mM/h), and 85 % conversion in 48 h, which are the highest reported for 18 food-safe mesophilic tagatose synthesis. We suggest that such an approach may be 19 invaluable for other enzymatic processes that are similarly kinetically-, thermodynamically-20 , and/or stability-limited. 65We use the food-safe engineered probiotic bacterium Lactobacillus plantarum as the 66 expression host due to its increasing relevance to biochemical and biomedical research 30,31 . 67This approach enabled ~ 50 % conversion of galactose to tagatose in 4 h (productivity of ~ 68 38 mmol tagatose L -1 h -1 ) ultimately reaching ~ 85% conversion after 48 h at high galactose 69 loading (300 mM) in batch culture. This is among the highest conversions and 70 productivities reported to date for tagatose production using a mesophilic enzyme. Such an 71 approach is expected to be applicable to other biocatalytic systems where similar trade-offs 72 between kinetics, thermodynamics, and/or stability pose hurdles to process development. 73 74 Results: 75Characterizing L. sakei LAI (LsLAI) limitations. 76 At high substrate loading (400mM galactose) and 37 °C, the reported optimal temperature 77 for this enzyme 32 , LsLAI purified from L. plantarum exhibited an initial forward reaction 78 (turnover) rate (kinitial) of 9.3 ± 0.3 s -1 , which is lower than the maximum reaction rate 79 possible by this enzyme of 17.0 ± 1.3 s -1 min -1 with its preferred substrate, arabinose, at 400 80 mM. Increasing the reaction temperature to 50 °C increased the initial reaction rate to 11.2 81 s -1 ( Fig. 1a) but was accompanied by rapid enzyme inactivation, which is consistent with 82 previous reports of thermal instability of this enzyme 32 . The enzyme exhibited first-order 83 degradation with a half-life (t½) ...

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d-Tagatose production in the presence of borate by resting Lactococcus lactis cells harboring Bifidobacterium longum l-arabinose isomerase

Cited by 35 publications

References 141 publications

Lactulose production from lactose by recombinant cellobiose 2‐epimerase in permeabilised Escherichia coli cells

Lactulose production from lactose by recombinant cellobiose 2‐epimerase in permeabilised Escherichia coli cells

Characterization of an <small>L</small>-Arabinose Isomerase from <i>Bacillus thermoglucosidasius</i> for <small>D</small>-Tagatose Production

Surpassing thermodynamic, kinetic, and stability barriers to isomerization catalysis for tagatose biosynthesis

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