Evaluating membrane technology for clarification of sugarcane juice

The sugar industry needs to find efficient methods in clarifying the raw sugarcane juice in order to improve the quality of the clarified juice and to reduce or eliminate the usage of chemicals (lime). Conventional clarifiers use heavy equipment which lead to high operating costs and associated environmental problems. In sugar mills, ensuring the production of juice of consistently high clarity and low colour through the clarification process is a challenging task. The variations in the incoming juice characteristics due to differences in cane variety, soil and growing conditions, weather patterns and season make this task even more challenging. Membrane filtration promises superior quality juice with better clarity, much lower viscosity and noticeable colour removal. Ultrafiltration of clarified sugarcane juice can be done through spiral wound or flat sheet filtration systems using polymeric membranes or tubular filtration systems using ceramic membranes. This review evaluates the applications of membrane technology in sugar industry all over the world and the need for it in the Australian sugar industry. This is an important first step to identify the appropriate types and applications of membranes.     

Studies on Pectolytic Enzymes of Molds

The process of apple juice clarification by pectolytic enzymes has been successfully observed turbidimetrically and macroscopically by heating of reaction mixtures. It has been shown that the process of apple juice clarification varies with the varieties and conditions of apple juices as well as with the sources of enzyme preparations. From a study of the turbidimetry of apple juice clarification, α method for determination of clarification values been described.     

Pectic Enzymes in the Clarification of Apple Juice

To know the role of pectic enzymes in the clarification reaction of apple juice, a simplified model for apple juice, that is, aqueous re-suspension of ultracentrifugal precipitates of apple juice, was employed. It was found that the precipitates (i.e., suspended materials) contained 36% of protein and that the surface of the suspended materials was negatively charged at pH 3.5. Positively charged colloids at pH 3.5 such as gelatin enhanced the clarification reaction or mutually coagulated with the suspended materials. While negatively charged colloids at pH 3.5, such as sodium alginate completely inhibited the clarification reaction. The direct participation of pectic enzymes in the clarification of apple juice was shown, and a supposed mechanism of the enzymic clarification was presented.     

Immobilization of polygalacturonase from Aspergillus niger onto activated polyethylene and its application in apple juice clarification

The present work is focused on efficient immobilization of polygalacturonase on polyethylene matrix, followed by its application in apple juice clarification. Immobilization of polygalacturonase on activated polyethylene and its use in apple juice clarification was not reported so far. Aspergillus niger Van Tieghem (MTCC 3323) produced polygalacturonase when grown in modified Riviere's medium containing pectin as single carbon source by fed-batch culture. The enzyme was precipitated with ethanol and purified by gel filtration chromatography (Sephacryl S-100) and immobilized onto glutaraldehyde-activated polyethylene. The method is very simple and time saving for enzyme immobilization. Various characteristics of immobilized enzyme such as optimum reaction temperature and pH, temperature and pH stability, binding kinetics, efficiency of binding, reusability and metal ion effect on immobilized enzymes were evaluated in comparison to the free enzyme. Both the free and immobilized enzyme showed maximum activity at a temperature of 45 degrees C and pH 4.8. Maximum binding efficiency was 38%. The immobilized enzyme was reusable for 3 cycles with 50% loss of activity after the third cycle. Twenty-four U of immobilized enzyme at 45 degrees C and 1 h incubation time increased the transmittance of the apple juice by about 55% at 650 nm. The immobilized enzyme can be of industrial advantage in terms of sturdiness, availability, inertness, low price, reusability and temperature stability.     

Use of a preparation from fungal pectin lyase in the food industry

A new enzyme preparation of fungal pectin lyase (EC 4.2.2.10) was shown to be useful for the production of cranberry juice and clarification of apple juice in the food industry. A comparative study showed that the preparation of pectin lyase is competitive with commercial pectinase products. The molecular weight of homogeneous pectin lyase was 38 kDa. Properties of the homogeneous enzyme were studied. This enzyme was most efficient in removing highly esterified pectin.     

Use of a preparation from fungal pectin lyase in the food industry

A new enzyme preparation of fungal pectin lyase (EC 4.2.2.10) was shown to be useful for the production of cranberry juice and clarification of apple juice in the food industry. A comparative study showed that the preparation of pectin lyase is competitive with commercial pectinase products. The molecular weight of homogeneous pectin lyase was 38 kDa. Properties of the homogeneous enzyme were studied. This enzyme was most efficient in removing highly esterified pectin.     

Pectic Enzymes in the Clarification of Apple Juice

Pectinesterase of Sclerotinia arachnidis was purified by 44 times. The clarification of apple juice with the purified pectinesterase and the formerly purified endo-polygalacturonase of Aspergillus saitoi was examined. The coexistence of pectinesterase and endo polygalacturonase was necessary for the complete clarification of apple juice. During the clarification reaction rapid decrease of viscosity and resultant coagulation of the suspended materials in apple juice were observed. The coagulated materials slowly precipitated leaving clear juice.

It was suggested from the result of electrophoresis that the positive charge existed inside of the suspended materials. The decrease in viscosity was supposed to correlate to pectin’s depolymerization which would result in revealing of positive charge inside. The probable mechanism of coagulation was attributed to the electrostatic neutralization between positive charge thus appeared and negative charge of still undegraded pectin.     

Studies on Pectolytic Enzymes of Molds

The clarification of apple juice has been studied using six pectolytic enzymes produced by Coniothyrium diplodiella, endo-PG (polygalacturonase) I, II and III, exo-PG and PE (pectinesterase) I and II. Each of these six enzymes had no effect on the clarification of apple juice when acted alone, whereas mixtures of any one of endo-PGs and PEs were all able to clarify the juice. Mixtures of exo-PG and either of PEs has no effect on the clarification. Clarifying activities of PG-PE mixtures were varied with the kind of endo-PG used in each mixture and not with the kind of PE. Clarifying activity of PG-PE mixture depended on either endo-PG or PE activities when the other was kept constant.

Crude enzyme from the mold and a mixture of the four PGs and PE in the ratio of the crude enzyme had essentially identical effect on apple juice as well as on artificial pectin and pectic acid.     

Membrane separations in biotechnology

Membranes have always been an integral part of biotechnology processes. The sterile filtration of fermentation media, purification buffers, and protein product pools is standard practice in industry. Microfiltration is also used extensively for medium exchange and harvest. Ultrafiltration can be found in virtually every biotechnology process. A significant number of mammalian cell processes use filtration as an integral part of the overall strategy for viral clearance. Depth filters have also seen widespread use for the clarification of both mammalian and bacterial feed streams. Improvements in membrane technology are now focused on high-resolution applications, including improved protein-virus separation, protein purification by high-performance tangential flow filtration and enhanced membrane chromatography. These developments will allow membranes to play an important role in the evolution of the next generation of biotechnology processes.     

Optimization and characterization of dextran membranes prepared by electrospinning

Dextran is soluble in both water and organic solvents, so it could be a versatile biomacromolecule for preparing nanofibrous electrospun membranes by blending with either water-soluble bioactive agents or hydrophobic biodegradable polymers for biomedical applications. We have formulated electrospun dextran membranes, and the effects of various processing parameters on the membrane properties were investigated. It was found that uniform nanofibrous dextran membranes could be formed by using water, DMSO/water, and DMSO/DMF mixtures as solvents through adjusting the processing conditions (solution concentration, voltage, and the distance between the electrode and the collecting plate). When water was used as a solvent, up to 10% (w/w) of bovine serum albumin (BSA) or lysozyme could be directly incorporated into the dextran electrospun membrane without compromising its morphology. No significant effect of the electrospinning process on lysozyme activity was observed. The composite electrospun membranes consisting of poly(D,L-lactide-co-glycolide) (PLGA) and dextran were obtained using DMSO/DMF (50/50, volume ratio) mixture as solvents. For cross-linking the electrospun membrane, dextran was modified by substitution of methacrylate groups at the hydroxyl sites. It was found that the electrospun membranes prepared from methacrylated dextran can be cured by UV irradiation in the presence of 1% of 2,2-dimethoxy-2-phenylacetophenone (DMPA) as a photoinitiator.     

聚氨酯泡沫固定化黑曲霉P-6021可同时产果胶酶和澄清果汁

以多孔聚氨酯泡沫(PUF)固定化黑曲霉P-6021可以实现菌丝体的摇瓶重复间歇发酵产酶,重复5个批次,菌体数目增多,产酶量上升,发酵液酶活达到664u/ml。以PUF固定化黑曲霉P-6021进行了同时产果胶酶和澄清苹果汁试验,以浑浊苹果汁基质发酵12h后, 产酶量可达到643u/ml,苹果汁基本澄清,透光率提高,粘度降低。表明固定化黑曲霉可以同时产果胶酶和澄清苹果汁,实现产酶与澄清过程的耦合。     

Single-stage chromatographic clarification of Chinese Hamster Ovary cell harvest reduces cost of protein production

A single-stage clarification was developed using a single-use chromatographic clarification device (CCD) to recover a recombinant protein from Chinese Hamster Ovary (CHO) harvest cell culture fluid (HCCF). Clarification of a CHO HCCF is a complex and costly process, involving multiple stages of centrifugation and/or depth filtration to remove cells and debris and to reduce process-related impurities such as host cell protein (HCP), nucleic acids, and lipids. When using depth filtration, the filter train consists of multiple filters of varying ratios, layers, pore sizes, and adsorptive properties. The depth filters, in combination with a 0.2-micron membrane filter, clarify the HCCF based on size-exclusion, adsorptive, and charge-based mechanisms, and provide robust bioburden control. Each stage of the clarification process requires time, labor, and utilities, with product loss at each step. Here, use of the 3M™ Harvest RC Chromatographic Clarifier, a single-stage CCD, is identified as an alternative strategy to a three-stage filtration train. The CCD results in less overall filter area, less volume for flushing, and higher yield. Using bioprocess cost modeling, the single-stage clarification process was compared to a three-stage filtration process. By compressing the CHO HCCF clarification to a single chromatographic stage, the overall cost of the clarification process was reduced by 17%–30%, depending on bioreactor scale. The main drivers for the cost reduction were reduced total filtration area, labor, time, and utilities. The benefits of the single-stage harvest process extended throughout the downstream process, resulting in a 25% relative increase in cumulative yield with comparable impurity clearance.     

Membrane processing of fruit juices and beverages: a review

Membrane technology for the processing of fruit juices and beverages has been applied mainly for clarification using ultrafiltration and microfiltration, and for concentration using reverse osmosis. The effects of product preparation, membrane selection, and operating parameters are important factors influencing filtration rate and product quality. Technological advances related to the development of new membranes, improvement in process engineering, and better understanding of fruit beverage constituents have expanded the range of membrane separation processes. Developments in novel membrane processes, including electrodialysis and pervaporation, increased the array of applications in combination with other technologies for alternate uses in fruit juices and beverages.     

Dissolution Improvement of Electrospun Nanofiber-Based Solid Dispersions for Acetaminophen

The objective of the present investigation was to prepare novel solid dispersions (SDs) of poorly water-soluble drugs with special microstructural characteristics using electrospinning process. With the hydrophilic polymer polyvinylpyrrolidone as the filament-forming polymer and acetaminophen (APAP) as the poorly water-soluble drug model, SDs having a continuous web structure, and in the form of non-woven nanofiber membranes, were successfully prepared. The electrospun nanofiber-based SDs were compared with those prepared from three traditional SD processes such as freeze-drying, vacuum drying, and heating drying. The surface morphologies, the drug physical status, and the drug-polymer interactions were investigated by scanning electron microscopy, differential scanning calorimetry, X-ray diffraction, and attenuated total reflectance Fourier transform infrared. In vitro dissolution tests demonstrated that the electrospun nanofibers released 93.8% of the APAP content in the first 2 minutes and that the dissolution rates of APAP from the different SDs had the following order: electrospun membrane > vacuum-dried membrane ≈ freeze-dried membrane > heat-dried membrane. Electrospun nanofiber-based SDs showed markedly better dissolution-improving effects than the other SDs, mainly due to their huge surface area, high porosity resulting from web structure, and the more homogeneous distribution of APAP in the nanofiber matrix.     

Downstream processing in the biotechnology industry

The biotechnology industry today employs recombinant bacteria, mammalian cells, and transgenic animals for the production of high-value therapeutic proteins. This article reviews the techniques employed in this industry for the recovery of these products. The methods reviewed extend from the centrifugation and membrane filtration for the initial clarification of crude culture media to the final purification of the products by a variety of membrane-based and chromatographic methods. The subject of process validation including validation of the removal of bacterial and viral contaminants from the final products is also discussed with special reference to the latest regulatory guidelines.     

Membrane Processing of Fruit Juices and Beverages: A Review

ABSTRACT:?

Membrane technology for the processing of fruit juices and beverages has been applied mainly for clarification using ultrafiltration and microfiltration, and for concentration using reverse osmosis. The effects of product preparation, membrane selection, and operating parameters are important factors influencing filtration rate and product quality. Technological advances related to the development of new membranes, improvement in process engineering, and better understanding of fruit beverage constituents have expanded the range of membrane separation processes. Developments in novel membrane processes, including electrodialysis and pervaporation, increased the array of applications in combination with other technologies for alternate uses in fruit juices and beverages.     

固定化果胶酶澄清果汁的条件及效果

利用固定化果胶酶对四种不同果汁澄清条件及效果进行研究,结果表明,固定化果胶酶澄清四种不同果汁的效果明显,其中澄清桔汁的果胶酶重复使用20次以上,酶活力及透光率仍可维持在80%以上,其最适反应条件是:果汁浓度50%;pH 3.0~3.5;温度45~50℃;反应时间2小时;酶量每毫升果汁0.05 g固定化果胶酶;澄清时间20小时。     

Anti-GA3-Me Antiserum with High Specificity toward the 13-Hydroxyl Group of C19-Gibberellins

Membrane clarification of green tea extract was studied as a treatment to reduce sediments in packaged drinks and as a pretreatment for concentration processes. The flux and variation of components were examined in dead-end and crossflow filtration with several types of membranes. In dead-end ultrafiltration, the flux reduction rate was small, although the initial flux was similar to the final flux in microfiltration. Prefiltration was effective in decreasing the reduction rate of flux. As the pore size of microfiltration membranes became smaller, the dry weight decreased gradually and the optical transmission at 660 nm increased. By ultrafiltration, 30–50% pectin, 3–11% catechins and, 7–20% caffeine were rejected. Crossflow filtration was effective in keeping the flux high. The ultrafiltration spiral membrane (pore size: 0.008 μm) was selected for repeated batch clarification of prefiltered green tea crude extract and showed reproducible performance.     

An effective,simple and low-cost pretreatment for culture clarification in tetanus toxoid production

Abstract

Chemically inactivated tetanus toxin (tetanus toxoid, TT), purified from cultures of a virulent Clostridium tetani strain, is the active pharmaceutical ingredient of anti-tetanus vaccines. Culture clarification for TT production and is usually performed by filtration-based techniques. Final clarification of the culture supernatant is achieved by passage through 0.2?µm pore size filtering membranes. Large particles removal (primary clarification) before final filtration (secondary clarification) reduces costs of the overall clarification process. With this aim, chitosan-induced particle aggregation was assessed as an alternative for primary clarification. Three chitosan variants were tested with similar results. Optimal clarification of culture supernatant was achieved by the addition of 8?mg chitosan per l of culture. Extrapolation analysis of filter sizing results indicate that 100?l of chitosan-treated supernatant can be finally filtered with a 0.6 m2 normal filtration cartridge of 0.45?+?0.2?µm pore size. The clarified material is compatible with current standard downstream processing techniques for TT purification. Thus, chitosan-induced particle aggregation is a suitable operation for primary clarification.     

Evaluation of membranes for use in on-line cell separation during mammalian cell perfusion processes

In this study two microporous hollow fibre membranes were evaluated for their use as cell retention device in continuous perfusion systems. A chemically modified permanent hydrophillic PTFE membrane and a hydrophilized PP membrane were tested. To investigate the filtration characteristics under process conditions each membrane was tested during a long term perfusion cultivation of a hybridoma cell line. In both cultivations the conditions influencing membrane filtration (e.g. transmembrane flux) were kept constant. Filtration behaviour was investigated by monitoring transmembrane pressure and protein permeability. Transmembrane pressure was measured on-line with an autoclavable piezo-resistive pressure sensor. Protein permeability was determined by quantitative evaluation of unreduced, Coomassie stained SDS-PAGE. The membrane fouling process influences the filtration characteristics of both membranes in a different way. After fermentation the PP membrane was blocked by a thick gel layer located in the big outer pores of the asymmetric membrane structure. The hydraulic resistance was higher but the protein permeability was slightly better than of the PTFE membrane. For this reason the PP membrane should be preferred. On the other hand, transmembrane pressure decreases slower when the PTFE membrane is used, which favours this membrane for long term cultivations, especially when low molecular weight proteins (<30 KD) are produced.Abbreviations PP Polypropylene - PTFE Polytetrafluoroethylene