Development of a continuous-flow system with immobilized biocatalysts towards sustainable bioprocessing

Naramittanakul, Apisit; Buttranon, Supacha; Petchsuk, Atitsa; Chaiyen, Pimchai; Weeranoppanant, Nopphon

doi:10.1039/d1re00189b

Cited by 18 publications

(23 citation statements)

References 177 publications

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“…For example, throughout our (relatively) long-term column experiments that lasted 48 h, the measured current was 0.024 A when a constant 5 V cell potential was applied (40.0 mg of NO 3 – –N/L and 50.0 mg/L Cl – ); in the batch experiments (17.5 mg of NO 3 – –N/L and 1420 mg/L Cl – ), the current ranged between 0.028 and 0.030 A when a constant 5 V cell potential was applied. In the column experiments, this result is not surprising as fresh feed was continuously added to the system, leading to a relatively stable aqueous environment . In the batch experiments, the relatively large volume and short experimental duration likely maintained consistent conditions in the reactor that minimized changes to current.…”

Section: Resultsmentioning

confidence: 95%

“…In the column experiments, this result is not surprising as fresh feed was continuously added to the system, leading to a relatively stable aqueous environment. 59 In the batch experiments, the relatively large volume and short experimental duration likely maintained consistent conditions in the reactor that minimized changes to current. These results indicate that the electrodes in the system remained stable under the investigated conditions.…”

Section: −mentioning

confidence: 99%

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Nitrate Removal in an Electrically Charged Granular-Activated Carbon Column

Muller

Yoshihara-Saint

et al. 2021

Environ. Sci. Technol.

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Nitrate removal from groundwater remains a challenge. Here, we report on the development of a flow-through, electrically charged, granularactivated carbon (GAC)-filled column, which effectively removes nitrate. In this system, the GAC functioned as an anode, while a titanium sheet acted as a cathode. The high removal rate of nitrate was achieved through a combination of electrosorption and electrochemical transformation to N 2 . The column could be readily regenerated in situ by reversing the polarity of the applied potential. We demonstrate that in the presence of chloride, the mechanism responsible for the observed nitrate removal involves a combination of electroadsorption of nitrate to the anodically charged GAC, electroreduction of nitrate to ammonium, and the oxidation of ammonium to N 2 gas by reactive chlorine and other oxidative radicals (with nearly 100% N 2 selectivity). Given the ubiquitous presence of chloride in groundwater, this method represents a ready, green, and sustainable treatment process with significant potential for the remediation of contaminated groundwater.

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Section: Resultsmentioning

confidence: 95%

Section: −mentioning

confidence: 99%

Nitrate Removal in an Electrically Charged Granular-Activated Carbon Column

Muller

Yoshihara-Saint

et al. 2021

Environ. Sci. Technol.

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“…Flow chemistry is an important tool for process intensification and has been reported to reduce reaction times concomitantly improving enantioselectivities by suppressing undesired side reactions. Additionally, it enhances safety and among others reduces reaction volumes [25][26][27][28][29][30][31][32]. At the same time, it requires the enzymes to be immobilised, which often improves enzyme stability.…”

Section: Introductionmentioning

confidence: 99%

Batch and Flow Nitroaldol Synthesis Catalysed by Granulicella tundricola Hydroxynitrile Lyase Immobilised on Celite R-633

et al. 2022

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Granulicella tundricola hydroxynitrile lyase (GtHNL) catalyses the synthesis of chiral (R)-cyanohydrins and (R)-β-nitro alcohols. The triple variant GtHNL-A40H/V42T/Q110H (GtHNL-3V) was immobilised on Celite R-633 and used in monophasic MTBE saturated with 100 mM KPi buffer pH 7 for the synthesis of (R)-2-nitro-1-phenylethanol (NPE) in batch and continuous flow systems. Nitromethane was used as a nucleophile. A total of 82% of (R)-NPE and excellent enantioselectivity (>99%) were achieved in the batch system after 24 hours of reaction time. GtHNL-3V on Celite R-633 was successfully recycled five times. During more recycling steps a significant decrease in yield was observed while the enantioselectivity remained excellent over eight cycles. The use of a flow system enabled the continuous synthesis of (R)-NPE. A total of 15% formation of (R)-NPE was reached using a flow rate of 0.1 mL min−1; unfortunately, the enzyme was not stable, and the yield decreased to 4% after 4 hours on stream. A similar yield was observed during 15 hours at a rate of 0.01 mL min−1. Surprisingly the use of a continuous flow system did not facilitate the process intensification. In fact, the batch system displayed a space-time-yield (STY/mgenzyme) of 0.10 g L−1 h−1 mgenzyme−1 whereas the flow system displayed 0.02 and 0.003 g L−1 h−1 mgenzyme−1 at 0.1 and 0.01 mL min−1, respectively. In general, the addition of 1 M nitromethane potentially changed the polarity of the reaction mixture affecting the stability of Celite-GtHNL-3V. The nature of the batch system maintained the reaction conditions better than the flow system. The higher yield and productivity observed for the batch system show that it is a superior system for the synthesis of (R)-NPE compared with the flow approach.

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“…An important strategy that has been largely overlooked to increase the overall enzyme performance (i. e., activity, stability, usability) in sialo‐oligosaccharide synthesis is immobilization. Solid‐supported preparations of the CSS and SiaT would facilitate recycling of the enzymes and help paving a way towards a continuous (flow) synthesis of sialo‐oligosaccharides [16,17] . Additionally, the enzymes can acquire enhanced stability through immobilization [16,18,19] .…”

Section: Introductionmentioning

confidence: 99%

“…Solid-supported preparations of the CSS and SiaT would facilitate recycling of the enzymes and help paving a way towards a continuous (flow) synthesis of sialo-oligosaccharides. [16,17] Additionally, the enzymes can acquire enhanced stability through immobilization. [16,18,19] Structural stabilization can be significant especially with multimeric enzymes which upon immobilization dissociate less readily into subunits than in solution.…”

Section: Introductionmentioning

confidence: 99%

Immobilization of CMP‐Sialic Acid Synthetase and α2,3‐Sialyltransferase for Cascade Synthesis of 3′‐Sialyl β‐D‐Galactoside with Enzyme Reuse

et al. 2022

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Sialo‐oligosaccharides are often synthesized via cascade reaction of CMP‐sialic acid synthetase (CSS) and sialyltransferase (SiaT). Here, we studied individual enzyme immobilization to develop solid‐supported preparations of the CSS from Neisseria meningitis (NmCSS) and the α2,3‐SiaT from Pasteurella dagmatis (PdSiaT). Oriented immobilization via N‐terminal His‐tag as well as “random” (orientationally uncontrolled) immobilization via multipoint covalent coupling gave catalyst preparations of each enzyme with low activity and effectiveness factor (η). We therefore constructed N‐terminal fusions of NmCSS and PdSiaT with the cationic binding module Zbasic2 and show individual immobilization of even the unpurified enzymes on sulfonate carrier (ReliSorb SP400) in excellent yields (≥95 %) and binding selectivities. For both enzymes in individual reactions, the initial η (Z‐NmCSS: 90 %; Z‐PdSiaT: 25 %) declined sharply with increasing enzyme loading and the maximum immobilized activity was 110 U/g carrier (η=27 %) for Z‐NmCSS, 7.5 U/g (η≤5 %) for Z‐PdSiaT. Supplied with neuraminic acid and cytidine 5′‐triphosphate (20 mM each), the immobilized enzymes promoted α2,3‐sialylation of the model substrate 4‐nitrophenyl β‐D‐galactoside (20 mM) in 85 % yield and could be recycled 5 times with only small loss in their overall synthetic activity (≤10 %).

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Development of a continuous-flow system with immobilized biocatalysts towards sustainable bioprocessing

Abstract: Immobilization methods have emerged as feasible solutions for increasing the re-usability of biocatalysts, and for simplifying their separation from the desired products. Immobilized biocatalysts can directly be applied to a...

Cited by 18 publications

References 177 publications

Nitrate Removal in an Electrically Charged Granular-Activated Carbon Column

Nitrate Removal in an Electrically Charged Granular-Activated Carbon Column

Batch and Flow Nitroaldol Synthesis Catalysed by Granulicella tundricola Hydroxynitrile Lyase Immobilised on Celite R-633

Immobilization of CMP‐Sialic Acid Synthetase and α2,3‐Sialyltransferase for Cascade Synthesis of 3′‐Sialyl β‐D‐Galactoside with Enzyme Reuse

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