Purity control of simulated moving bed based on advanced fuzzy controller

Simulated moving bed (SMB) technology is considered one of the most successful techniques in chromatographic separation. However, due to the nonlinearity caused by discrete events and sensitivity to numerous separation performance parameters, purity control in SMB systems has been a challenging issue. Fuzzy controllers are increasingly popular in industrial environments due to their simplicity and effectiveness in handling nonlinearity. However, traditional fuzzy controllers used in industry often overlook considerations of error acceleration, resulting in slight deviations from target values under steady-state conditions and oscillatory behavior when system parameters change. This study proposes an advanced fuzzy controller, where in a series of experiments, the purity control targets for component B are set at 94% and 96%, and for component A are set at 96% and 96%, respectively. Experimental results indicate that the advanced fuzzy controller achieves higher precision, with an average deviation of around 0.1%, for both components B and A. Importantly, under variations in adsorbent parameter(from 0.01 to 0.03), feed concentration(from 4.5 to 5.2), and switching time(from 178 to 182), the experimental results demonstrate smoother control with the advanced controller, particularly when oscillations occur with conventional fuzzy controllers due to switching time variations, indicating robust control with the advanced fuzzy controller.

Highly Efficient Production of UDP-Glucose from Sucrose via the Semirational Engineering of Sucrose Synthase and a Cascade Route Design

Nucleotide sugars are essential precursors for carbohydrate synthesis but are in scarce supply. Uridine diphosphate (UDP)-glucose is a core building block in nucleotide sugar preparation, making its efficient synthesis critical. Here, a process for producing valuable UDP-glucose and functional mannose from sucrose was established and improved via a semirational sucrose synthase (SuSy) design and the accurate D-mannose isomerase (MIase) cascade. Engineered SuSy exhibited enzyme activity 2.2-fold greater than that of the WT. The structural analysis identified a latch-hinge combination as the hotspot for enhancing enzyme activity. Coupling MIase, process optimization, and reaction kinetic analysis revealed that MIase addition during the high-speed UDP-glucose synthesis phase distinctly accelerated the entire process. The simultaneous triggering of enzyme modules halved the reaction time and significantly increased the UDP-glucose yield. A maximum UDP-glucose yield of 83%, space-time yield of 70 g/L/h, and mannose yield of 32% were achieved. This novel and efficient strategy for sucrose value-added exploitation has industrial promise.

Applicant hierarchical fuzzy controller for concentration control of simulated moving bed

Simulated moving bed (SMB) is a kind of continuous process which can increase the efficiency of adsorbents in the adsorbent bed. It contains several sectors of flow rate, the switching time of valves and many other possible influencing variables, moreover, these parameters are highly sensitive, so it is very difficult to achieve precise prediction and control. Model predictive control and PID controller are often used in industrial system. Model predictive control needs a lot of accurate industry experience data, and PID controller depends on the selection of control parameters. Therefore, SMB needs an intelligent controller to bypass those complex mechanisms and parameter adjustment processes. This paper we propose the hierarchical fuzzy controller fuzzy controller which is applied to the SMB system to observe the final concentration. Compared with the PID and MPC controller, it is found that the hierarchical fuzzy controller can control good without knowing the system parameters too accurately.

Batch chromatography with recycle lag. I-Concept and design

This is the first of a two-part study in which we explore the concept of batch chromatography with recycle lag, concluding with the design, construction, and experimental validation of a prototype that embodies the physical realization of this concept. Moreover, the apparatus is simple to set up in particular in view of large-scale applications. Here the theory behind batch chromatography with recycle lag is revisited and extended, with emphasis on the mathematical formulation and procedure for deriving the single-column batch analogue of any variant of multicolumn simulated countercurrent chromatography. By resorting to selected examples, namely GE Healthcare Bio-science's three-column periodic countercurrent chromatography, Novasep's sequential multicolumn chromatography, and a few hypothetical multicolumn processes, we discuss how the theory can be operationalized. Finally, we conclude by describing the design of a device or apparatus-an eluate recycling device (ERD)-to physically realize the proposed concept. The ERD implements an approximate "first in, first out" method for organizing and manipulating the to-be-recycled fractions of eluate collected from the chromatography column, where the oldest (first) amount fluid, or 'head' of the fraction, is the first to exit and be recycled to the column.

Batch chromatography with recycle lag. II-Physical realization and experimental validation

This is the second of a two-part study in which we explore the concept of batch chromatography with recycle lag, concluding with the design, construction, and experimental validation of a prototype-an eluate recycling device (ERD)-that embodies the physical realization of this concept. The ERD implements an approximate "first in, first out" method of organizing and manipulating the to-be-recycled fractions of eluate collected from the chromatography column, where the oldest (first) amount fluid, or 'head' of the fraction, is the first to exit and be recycled back to the column. Moreover, the apparatus is simple to set up in particular in view of large-scale applications. Here we detail the construction of the ERD and assembly of a setup to interconnect the ERD and a chromatography column. Through the coordinated operation of two-way valves and two-position six-port switching valves it is possible to implement a diverse set of configurations or operating modes interconnecting the chromatography column and the ERD. The setup is validated experimentally with success using the separation of a nucleoside mixture by reversed phase chromatography as a model problem. It is also shown that by redesigning the fluid distributor using 3D printing technology the ERD performance can be improved.

Highly efficient recovery of xylobiose from xylooligosaccharides using a simulated moving bed method

Xylobiose (X2), which is currently available from xylooligosaccharides (XOS), has been reported to have outstanding prebiotic function and to be highly suitable for application in food industries. This has sparked an interest in the economical production of X2 of high purity (> 99%) in food and prebiotic industries. To address such issue, we developed a highly-efficient chromatographic method for the recovery of X2 from XOS with high purity and high recovery. As a first step for this work, an eligible adsorbent for a large-scale separation between X2 and other XOS components was selected. For the selected adsorbent, a single-column experiment was carried out to determine the intrinsic parameters of all the XOS components, which were then used in the optimal design of the continuous X2-recovery process based on a simulated moving bed (SMB) chromatographic method. Finally, the performance of the designed X2-recovery SMB process was verified by the relevant SMB experiments, which confirmed that the developed process in this study could recover X2 from XOS with the purity of 99.5% and the recovery of 92.3% on a continuous-separation mode. The results of this study will be useful in enabling the economical production of high-purity X2 on a large scale.

Continuous counter-current chromatography for capture and polishing steps in biopharmaceutical production

The economic advantages of continuous processing of biopharmaceuticals, which include smaller equipment and faster, efficient processes, have increased interest in this technology over the past decade. Continuous processes can also improve quality assurance and enable greater controllability, consistent with the quality initiatives of the FDA. Here, we discuss different continuous multi-column chromatography processes. Differences in the capture and polishing steps result in two different types of continuous processes that employ counter-current column movement. Continuous-capture processes are associated with increased productivity per cycle and decreased buffer consumption, whereas the typical purity-yield trade-off of classical batch chromatography can be surmounted by continuous processes for polishing applications. In the context of continuous manufacturing, different but complementary chromatographic columns or devices are typically combined to improve overall process performance and avoid unnecessary product storage. In the following, these various processes, their performances compared with batch processing and resulting product quality are discussed based on a review of the literature. Based on various examples of applications, primarily monoclonal antibody production processes, conclusions are drawn about the future of these continuous-manufacturing technologies.

Continuous recovery of valine in a model mixture of amino acids and salt from Corynebacterium bacteria fermentation using a simulated moving bed chromatography

The economical efficiency of valine production in related industries is largely affected by the performance of a valine separation process, in which valine is to be separated from leucine, alanine, and ammonium sulfate. Such separation is currently handled by a batch-mode hybrid process based on ion-exchange and crystallization schemes. To make a substantial improvement in the economical efficiency of an industrial valine production, such a batch-mode process based on two different separation schemes needs to be converted into a continuous-mode separation process based on a single separation scheme. To address this issue, a simulated moving bed (SMB) technology was applied in this study to the development of a continuous-mode valine-separation chromatographic process with uniformity in adsorbent and liquid phases. It was first found that a Chromalite-PCG600C resin could be eligible for the adsorbent of such process, particularly in an industrial scale. The intrinsic parameters of each component on the Chromalite-PCG600C adsorbent were determined and then utilized in selecting a proper set of configurations for SMB units, columns, and ports, under which the SMB operating parameters were optimized with a genetic algorithm. Finally, the optimized SMB based on the selected configurations was tested experimentally, which confirmed its effectiveness in continuous separation of valine from leucine, alanine, ammonium sulfate with high purity, high yield, high throughput, and high valine product concentration. It is thus expected that the developed SMB process in this study will be able to serve as one of the trustworthy ways of improving the economical efficiency of an industrial valine production process.

Simulated moving bed separation of agarose-hydrolyzate components for biofuel production from marine biomass

The economically-efficient separation of galactose, levulinic acid (LA), and 5-hydroxymethylfurfural (5-HMF) in acid hydrolyzate of agarose has been a key issue in the area of biofuel production from marine biomass. To address this issue, an optimal simulated moving bed (SMB) process for continuous separation of the three agarose-hydrolyzate components with high purities, high yields, and high throughput was developed in this study. As a first step for this task, the adsorption isotherm and mass-transfer parameters of each component on the qualified adsorbent were determined through a series of multiple frontal experiments. The determined parameters were then used in optimizing the SMB process for the considered separation. Finally, the optimized SMB process was tested experimentally using a self-assembled SMB unit with four zones. The SMB experimental results and the relevant computer simulations verified that the developed process in this study was quite successful in the economically-efficient separation of galactose, LA, and 5-HMF in a continuous mode with high purities and high yields. It is thus expected that the developed SMB process in this study will be able to serve as one of the trustworthy ways of improving the economic feasibility of biofuel production from marine biomass.

Step gradients in 3-zone simulated moving bed chromatography. Application to the purification of antibodies and bone morphogenetic protein-2

The simulated moving bed (SMB) technology is a proven tool for efficient separation of binary mixtures. However, relying on isocratic conditions limits the applicability of the classical SMB approach when considering the field of bioseparations. Here, the use of gradients opens up new possibilities. A gradient in a SMB process can be established by using different solvent strengths in the incoming feed and desorbent streams, resulting in two internal plateaus of elution strength. Thus, compared to the conventional process, the overall amount of solvent needed can be reduced, productivity can be increased and more concentrated product streams can be obtained. In this contribution, two case studies will be presented. At first, the separation of bovine IgG from lysozyme will be analyzed as a model system. Antibodies are a common target substance in bio-chromatography, as therapeutic monoclonal antibodies are among the most promising biopharmaceuticals. Using adsorption data obtained from single-column experiments, an appropriate SMB process was designed and implemented. The second target component is the active dimeric form of the bone morphogenetic protein-2 (BMP-2). This protein was isolated from a renaturation solution, which also contained its inactive monomeric form as well as other undefined proteins from the bacterial production strain. A 3-zone open-loop gradient-SMB approach was used successfully for both separations.

Optimal design and experimental validation of synchronous, asynchronous and flow-modulated, simulated moving-bed processes using a single-column setup

The performance of asynchronous (Varicol) and flow-modulated (PowerFeed) simulated moving-bed processes, as well as their combination into a single hybrid scheme, are studied both experimentally and by numerical simulation. A recently developed single-column experimental setup is employed to demonstrate the feasibility of the various schemes, explore the effect of their major operating parameters, and illustrate the performance enhancements that are obtained when these schemes are properly optimized. The experimental feasibility and effectiveness of the various schemes are assessed by running and comparing optimized configurations for the linear separation of two nucleosides on a high-performance reversed-phase stationary phase.

Experimental assessment of simulated moving bed and varicol processes using a single-column setup

A novel single-column setup for experimentally reproducing the steady periodic behavior of simulated countercurrent multicolumn chromatography is presented. The system relies on accurate online monitoring of the outlet effluent composition, processing the measured data through a node balance, and feeding it back into the column with an appropriate time delay using a multi-pump configuration to reproduce the desired inlet stream. The feasibility of the proposed system is demonstrated on the linear separation of two nucleosides using three different column configurations, which include both synchronous and asynchronous port switchings. By judiciously selecting the switching interval for process startup and applying a model-based startup procedure, the periodic state can be attained in just one or two cycles. Therefore, mobile phase and solute consumptions required to experimentally reproduce the periodic state of the equivalent multicolumn process are reduced to a minimum. This may be an economic, optimal manner of experimentally testing a set of operating conditions or cycle policy to achieve a given separation performance for a new multicolumn chromatographic separation.

Enantiomeric separation and determination of absolute stereochemistry of asymmetric molecules in drug discovery—Building chiral technology toolboxes

The application of Chiral Technology, or the (extensive) use of techniques or tools for the determination of absolute stereochemistry and the enantiomeric or chiral separation of racemic small molecule potential lead compounds, has been critical to successfully discovering and developing chiral drugs in the pharmaceutical industry. This has been due to the rapid increase over the past 10-15 years in potential drug candidates containing one or more asymmetric centers. Based on the experiences of one pharmaceutical company, a summary of the establishment of a Chiral Technology toolbox, including the implementation of known tools as well as the design, development, and implementation of new Chiral Technology tools, is provided.