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In this work, the laccase from Trametes versicolor was immobilized in highly porous silica monoliths (0.6-cm diameter, 0.5-cm length). These monoliths feature a unique homogeneous network of interconnected macropores (20 μm) with mesopores (20 nm) in the skeleton and a high specific surface area (330 m

International audience; elf-standing binderless FAU-X monoliths with hierarchical trimodal porosity have been synthesized for the first time by a double pseudomorphic transformation. Parent silica monoliths obtained by the combination of spinodal decomposition and sol-gel process have first been synthesized. The silica monoliths have been then transformed into silica-alumina monoliths (0.25

International audience; In the present work, pharmaceutical micropollutant degradation by laccase immobilized on silica through an innovative process is proposed. The influence of different parameters on the immobilization conditions was evaluated by a 23 full factorial design, and parameters leading to the highest activity were identified. Under these conditions, laccase activity reached 14 ± 2 U g-1 of silica with a protein immobilization yield of 35%. The biocatalyst characterization did not show any change in pH and thermal stabilities but enhanced the long-term storage of laccases. Immobilized T. versicolor laccases were then tested to remove four pharmaceutical micropollutants (amoxicillin, ciprofloxacin, carbamazepine, and sulfamethoxazole) in the presence of redox mediators (syringaldehyde, p-coumaric acid, and ABTS). High removal yields (50–100% according to the pollutant) were obtained within 4 h of treatment due to the synergistic effect of laccase-mediator biotransformation and adsorption on the support. Overall, the pharmaceuticals’ removal efficiency was highly influenced by their physicochemical properties; however, the presence of redox mediators impacted not only the oxidation mechanism but also the interactions between the biocatalyst and micropollutants. Finally, the reusability of the biocatalyst was proved during 7 degradation cycles.

International audience; Millimeter-size beads of gelatin are manufactured by dripping process to give enzyme supports qualified for micropollutants biodegradation in alternative wastewater treatment. The bead diameter is dependent on the tip diameter, the gelatin solution viscosity and the swelling of polymer chains in the collecting bath. Chemical crosslinking was performed with glutaraldehyde using optimal concentration to give mechanical and thermal properties suitable for application in stirred reactor in aqueous medium. Laccases from Trametes versicolor are grafted on the gelatin beads with glutaraldehyde. Sixty percentage of the initial enzymatic activity, evaluated by the oxidation of 2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt (ABTS) is maintained after 10 successive cycles of reaction. Thermal stability at 60°C of immobilized biocatalysts is improved when compared to free enzymes (45% vs 10% of relative activity after 6 h of incubation). The simplicity of the procedure to form gelatin beads and their properties make them promising bio-based and biodegradable support for enzyme immobilization.

Spent brewer’s yeast (Saccharomyces sp.), the second most generated by-product from the brewing industry, contains bioactive and nutritional compounds with high added value such as proteins (40–50%), polysaccharides, fibers and vitamins. Molecules of interest from agro-industrial by-products need to be extracted, separated, concentrated, and/or purified so that a minimum purity level is achieved, allowing its application. Enzymatic hydrolysis has been successfully used in the production of peptides and protein hydrolysates. The obtained hydrolysates require efficient downstream processes such as membrane technology, which is an important tool for the recovery of thermolabile and sensitive compounds from complex mixtures, with low energy consumption and high specificity. The integration of membrane techniques that promote the separation through sieving and charge-based mechanisms is of great interest to improve the purity of the recovered fractions. This review is specifically addressed to the application of membrane technologies for the recovery of peptides from yeast protein hydrolysates. Fundamental concepts and practical aspects relative to the ultrafiltration of agro-industrial protein hydrolysates will be described. Challenges and perspectives involving the recovery of peptides from yeast protein hydrolysates will be presented and thoroughly discussed.

High-performance liquid chromatography with diode array (HPLC-DAD) and liquid chromatograph triple quadrupole mass spectrometry (HPLC-MS/MS) were used to characterize raw and fermented coffee pulps in terms of their phenolic composition and caffeine content. The qualitative analysis showed no significant differences between the raw and the fermented pulps. Free hydroxycinnamic acids (HAs) were mainly chlorogenic acids, with 5-caffeoylquinic acid as the major compound. Bound HAs released caffeic acids during alkaline hydrolysis, and no bound ferulic and p-coumaric acids were detected. The fermentation process allowed the detoxification of the pulp from caffeine by 50%, while significantly reducing the amounts of residue by 64%. Moreover, the fermented products could be further processed to provide high added-value molecules with potential industrial applications, providing a new source of income for the small coffee producers.

Carbon dioxide constitutes one of the largest carbon feedstocks for fuel production. This work demonstrates that an environmental bacterial consortium grown on methane is able to directly and selectively reduce CO2 into formate. The conversion was carried out at 30°C and atmospheric pressure, without any the addition of organic molecules (such as cofactor), photons or H2 to the reaction medium. When exposed to a CO2:air (1:1 v/v) mixture, the consortium was able to produce 280 ± 10 mg·g dry cell−1 of formate in 15 days. A control experiment performed solely with air coupled to NMR analysis suggested that at least 17% of the formate was produced from direct CO2 reduction. The formate produced could be used as a precursor for methanol production from methane by methanotrophic bacteria or it could be acidified to feed Direct Formic Acid Fuel Cells.

Development of new strategies to add-value to agro-industrial by-products are of environmental and economical importance. Innovative and low-cost sources of protein and bioactive peptides have been explored worldwide. Spent brewer's yeast (SBY) is the second most relevant by-product from the brewing industry, and despite its nutritional (about 50% protein, dry weight) and technological potential, it is still underused or needs to be disposed of. SBY cells need to be disrupted to release intracellular and cell wall proteins. This procedure has been performed using autolysis, glass bead milling, enzymatic hydrolysis and ultrasound processing. Enzymatic treatment is usually performed without prior purification and is a challenging process, which involves multiple factors, but has been successfully used as a strategy to add value to agro-industrial by-products. Scope and approach: in this review, we particularly focused on enzymatic hydrolysis as a strategy to promote SBY valorisation, illustrating the state-of-the-art processes used to produce protein extracts from this material as well as exploring fundamental concepts related to the particularities of yeast cell disruption and protein hydrolysis. Furthermore, innovative applications of value-added yeast by-products in food, biotechnological and pharmaceutical industries are presented and discussed. Key findings and conclusions: the discovery of valuable compounds found in spent yeasts as well as the development of new processing methodologies have been widening the possibilities of reuse and transformation of SBY as an ingredient and innovative matrix. Once released, yeast proteins and peptides may be applied as an innovative non-animal protein source or a functional and bioactive ingredient.

Spent brewer's yeast (SBY) application as a new source of peptides depends on the development of proper downstream processes. This work aimed to separate yeast hydrolysate peptides from sugars and ribonucleic acids (RNA) by a 3-step designed fractionation process using ceramic ultra and nanofiltration following two sequences: (1) 50, 8 and 1 kDa and (2) 15, 8 and 1 kDa molecular weight cut-off (MWCO) membranes. In step one, 15 kDa MWCO membrane retained more components and increased performance of subsequent steps, when compared to 50 kDa. Peptide composition of the initial hydrolysate was gradually changed until 90% of the peptides smaller than 1 kg mol−1 were found in the final permeate. Fractionation increased peptide purity regarding RNA and total sugars up to 1.7 and 2.7-fold, respectively. Innovative protein-rich ingredients from SBY residue with an RNA content as low as 1.4% were produced by membrane separation technology. High quality ingredients presented different peptide profiles and great potential in food and pharmaceutical industries applications.

This work concerns the intensification of membrane processes by coupling the Joule effect with two membrane processes: pervaporation and sweeping gas membrane distillation. For this purpose, conducting metallic hollow fibers impregnated or coated with polydimethyl siloxane were simultaneously used as membrane and heating electric resistance. The application of an electrical potential resulted in an enhancement of 40% of the water vapor permeate flux in sweep gas membrane distillation. However, the flux enhancement is the result not only of the heating on the membrane vicinity but also on the enhancement of the feed temperature. In the case of pervaporation of aqueous ethanol solutions (20%), the direct heating of fibers allowed improving by 100% the ethanol permeate flux while increasing the process selectivity.

This work investigated membrane selectivity and fouling after the dead-end ultrafiltration of protein hydrolysate from spent brewer's yeast, a high protein brewing by-product. Ultrafiltration (UF) experiments were carried out with regenerated cellulose (RC) and polyethersulfone (PES) membranes of 30 kDa molecular weight cut-off at different pH values (5 and 8). Higher peptide retention (60% of total solids and 83% of peptides) was achieved using PES and a feed pH of 5. Ribonucleic acids were successfully separated from the peptide-rich fraction. The protein hydrolysate at pH 8 showed less susceptibility to the adsorption of proteins and smaller resistance to mass transfer. Similarities in the zeta potential of membranes and feed solution suggested that foulants aggregated in the surface of membranes by weak physical adsorption. Peptides were confirmed by FT-IR analysis as the main foulants. Hydrophilic membranes and feed at pH 8 increased UF performance of spent brewer's yeast hydrolysate.

In this study the enzymatic degradation of hormones and endocrine disrupting compounds (EDCs) was investigated in artificial mixtures and in real wastewater by fungal laccases (Trametes versicolor, Myceliophthora thermophila). Several studies have already reported the successful enzymatic degradation of EDCs. However, with regards to a large-scale application, the influence of some factors such as enzyme immobilization and costs are often lacking. Furthermore, the majority of studies investigated the removal of EDCs by chemical analysis only, while our main interest was to use bioassays to study the decrease in the endocrine activity. The removal of estrogenic, androgenic, and antiandrogenic activity was assessed by yeast-based reporter gene assays and the degradation of industrial chemicals by an additional chemical analysis. It was demonstrated that the degradation of hormones and EDCs by laccases is feasible even at very low enzyme concentrations (2.8 ABTS U/L). In the artificial mixtures the main remo...

In this study, coffee pulp was used as carbon source in solid-state fermentation to produce a phenol-rich extract for industrial applications. Fermentations were carried out at laboratory (0.4 kg), semi-pilot (12 kg) and pilot (90 kg) scales in presence of 2.5 g kg−1 yeast strains and with three different coffee pulp materials. The extract stability was investigated using different stabilizing agents: SO2, ascorbic and acetic acids. Then, a study was conducted to determine the effect of ultrasound treatment on extraction yields. Results showed that higher concentrations of chlorogenic acids were obtained with fermentation without ultrasound treatment and by adding sulfite at 0.5 wt% at 8 h of fermentation. Despite of variations in coffee pulp composition, the process was validated at semi-pilot and pilot scales, providing an extract 400% richer in chlorogenic acids (600 mg kg of coffee pulp) and with lower sugar amounts to separate during the downstream processing. Universidad de Costa Rica/[735-A2-502]/UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro Nacional de Ciencia y Tecnología de Alimentos (CITA)

Bio-catalytic processes have recently attracted attention as an interesting option for the degradation of persistent pollutants as they are capable to catalyze specific reactions at mild conditions and low environmental impact. In this work the potential to transform pharmaceutical micropollutants of a novel laccase from Pycnoporus sanguineus CS43 was compared to the commercial laccases Trametes versicolor and Myceliophtora thermophila. In the absence of redox mediators micropollutants were resistant to degradation, except for the antibiotic amoxicillin that was transformed by all laccases. The influence of natural and synthetic redox mediators (syringaldehyde, p-coumaric acid and ABTS) on the laccase oxidation system was investigated. Results showed the degradation of a complex mixture of pharmaceuticals is both compound and redox mediator dependent. Syringaldehyde resulted as the best redox mediator allowing the highest degradation yields of the antibiotics amoxicillin (80%), sulfamethoxazole (100%) and ciprofloxacin (40%) within 3 h treatment. Overall, commercial laccases showed better catalytic performance in comparison to P. sanguineus CS43 laccase especially in the presence of redox mediators. The successful transformation of pharmaceuticals by the combined action of different laccases and redox mediators demonstrate the potential of these systems for the removal of complex pollutant matrices.

Erythromycin is an antibiotic considered as a recalcitrant pollutant because it is currently found in treated wastewaters. In addition, traces of antibiotics are a threatening ecological issue as these compounds are biologically active even at very low concentrations (ng L ⿿1 ). In this work, we studied enzymatic degradation of this antibiotic in model aqueous solutions containing 20 mg L ⿿1 erythromycin. We used as the biocatalyst an EreB esterase obtained from a genetically modified Escherichia coli W3110 strain carrying the EreB overexpression plasmid. Experiments were carried out with different reactor and biocatalyst configurations (free and immobilized by covalent grafting or adsorption). Free enzymes showed very high activity leading to erythromycin depletion. Experiments with the biocatalyst immobilized by adsorption using an enzymatic membrane reactor showed that even if EreB initially lost part of its activity, it was stabilized and able to continuously degrade erythromycin at a rate of 15.8 mg h ⿿1 for 100 h.

This work aimed to further investigate microfiltration with diafiltration to obtain a rich carotenoid extract from the solid by-product of cashew apple (Anacardium occidentale L.) juice processing. This solid residue called cashew fibers is rich in bioactive compounds, especially carotenoids. After mixing with water and pressing, an aqueous suspension was obtained and processed by crossflow microfiltration (40 °C) using tubular ceramic membrane with 0.2 μm pore diameter. Permeate flux, which increased with transmembrane pressure, could be maintained above 100 L·h−1·m−2 at high volume reduction ratio by coupling mechanical extraction with enzyme liquefaction. The concentration step led to an increase of the carotenoid content by up to 19-fold and the diafiltration step allowed the carotenoid purity to be multiplied by 5. The impact of the process on the retentate characteristics was assessed using a model based on simple assumptions. This calculation tool can easily be implemented and is helpful for choosing the operating conditions, to minimize water consumption as well as effluent production.

International audience; In the whole food production chain, from the farm to the fork, food manufacturing steps have a large environmental impact. Despite significant efforts made to optimize heat recovery or water consumption, conventional food processing remains poorly efficient in terms of energy requirements and waste management. Therefore, in the few last decades, much research has focused on the development of alternative non-thermal technologies. Some of them, such as membrane separation processes, hydrostatic or dynamic high pressure, dense phase or high-pressure carbon dioxide, and pulsed electric fields (PEFs) have been extensively studied for cold pasteurization, concentration, extraction, or food functionalization. However, it is still difficult to evaluate the actual advantages or limits of these innovative processing technologies to replace conventional processes. Thus, the overall aim of this paper is to present an overview of the most relevant studies dealing with the potentialities and limits of these non-thermal technologies to improve sustainability of food processing. After a brief presentation of the physical principles of these technologies, the paper illustrates how these technologies could play a decisive role for sustainable food preservation or valorization of raw materials and by-products.

This work revolves around the use of porous metal hollow fibers in membrane distillation. Various stages are covered, starting from membrane synthesis up to the testing of a pilot scale membrane module. Mechanically stable metal hollow fibers have been synthesized by phase inversion of a stainless steel particle loaded polymer solution, followed by thermal treatment to remove the polymer and sinter the particles together. The pore surface of the metal fibers has been made hydrophobic by functionalization with polydimethylsiloxane or stearic acid. A water evaporation flux of 0.2 kg h−1 m−2 was obtained at a feed water temperature of 333 K and a sweep gas flow rate of 135 L h−1 (Reair=2458) with pure water as feed. Under similar operating conditions, an evaporation flux of 0.14 kg h−1 m−2 was achieved when a 600 g L−1 sucrose solution was used as feed.

A mathematical model to simulate the performance of enzymatic membrane reactors was developed. It was applied to investigate the effectiveness of laccase immobilized over ceramic membranes for the degradation of tetracycline, a common antibiotic appearing as micropollutant in effluents of WWTPs. A process based on large-scale enzymatic membrane reactors in series was proposed for the treatment of the effluents from municipal, hospital and industrial wastewater treatment plants (WWTPs). The obtained results demonstrated the need for high improvements in the amount of enzyme grafted on the membranes or on enzymatic kinetics to afford the technical and economic competitiveness of the investigated designs and the possibility to be implemented within existing installations.

This paper describes the characterization of gelatin–ceramic membranes grafted with laccase from Trametes versicolor for the degradation of pharmaceutical pollutants. Tetracycline was chosen as a model substrate to confirm the optimization of the grafting protocol using two kinds of microfiltration membranes with pore diameters equal to 0.2 and 1.4 µm. The preparation of the enzymatic membranes was optimized by varying the concentrations of the enzyme and gelatin solutions used as well as by measurement of active support permeability. An immunogold labeling method coupled with scanning electron microscopy was applied for a first time to determine the spatial distribution of enzymes on the membranes. The amount and distribution of the grafted enzymes were then correlated with the tetracycline depletion observed with the enzymatic membranes.

A model was developed to simulate tubular enzymatic membrane reactors under three different configurations: dead-end, tangential flow with a porous enzymatic membrane and a non-permeable enzymatic wall. The simulations were applied to analyze the influence of reactor configuration, kinetics and mass transport conditions over the reactor performance in order to identify the main aspects to be taken into consideration for attaining optimal designs. The non-permeable enzymatic wall configuration under the evaluated conditions seems to be more valuable than the dead-end case in terms of substrate conversion and the tangential configuration looked more favorable to promote the best conversion in the permeate but not in the retentate. It was demonstrated that for a similar value, the Damkohler number can result in very dissimilar performances. The simulated results demonstrated that the most significant variable of the global performance of the enzymatic membrane reactors is the reaction kinetics: fast reactions attained very considerable conversion values under very different conditions.

Herein, we report the development of immobilized laccase based membrane bioreactor as a novel bio-catalytic system for the degradation of emerging endocrine disruptor i.e., Bisphenol A. Two laccase forms i.e. (1) in-house isolated and purified from an indigenous white-rot fungi Pycnoporus sanguineus (CS43) and (2) Trametes versicolor (commercial laccase from Sigma-Aldrich®) were immobilized on a multi-channel ceramic membrane (1.4μm in diameter) using 4% glutaraldehyde as a cross-linking agent. The immobilization yield and bisphenol A degradation activities of immobilized laccases were recorded at various pH levels. The surface topographies of immobilized-laccase membranes were accessed by scanning electron microscopy. In this study, 100% degradation of bisphenol A (20mg/L) was achieved in less than 24h in the presence of laccase from P. sanguineus (CS43) (620.55±14.85U/L) and T. versicolor (620.55±14.85U/L). The enzymes showed an optimal activity at pH 5 and 5.4 with a degradation rate of 204.8±1.8 and 79.0±0.1μmol/min/U for P. sanguineus (CS43) and T. versicolor, respectively. In conclusion, the highest immobilization of unit per square centimeter and efficient degradation potentiality strongly recommend the newly developed immobilized laccase based membrane bioreactor as a novel tool to tackle emerging contaminants degradation issues.

The production of fish protein hydrolysates (FPH) is a promising route to add value to fish by-products due to their potential application as a source of interest peptide fractions. Using Alcalase for hydrolysis of tuna dark muscle by-product, the influence of enzyme/substrate ratio and hydrolysis time on the rate of interest peptide fractions (1–4 kDa) was studied. The rate of this fraction obtained under optimized conditions (temperature 55 °C, pH 8.5, enzyme/substrate ratio of 1% and 60 min of hydrolysis reaction) was 26%. The performance of the combined process associating ultrafiltration and nanofiltration membranes was evaluated for fractionation of produced hydrolysate in order to isolate fractions enriched in peptides of specific molecular weight (MW). The interest peptide fraction (1–4 kDa) was isolated and the positive effect of diafiltration on peptide purification process was underlined. The peptide fractions produced have a high nutritional quality which can be used in human nutrition and they have a potential for applications in aquaculture diets.

The aim of this work is to develop a two-step membrane separation process enabling the fractionation of protein hydrolysates obtained from enzymatic hydrolysis of tuna by-products. A screening of the more appropriate UF and NF membranes was first performed in dead-end and tangential filtration cells with a model solution prepared from a commercial fish hydrolysate (Prolastin®). Optimization of UF and NF steps was then investigated through the impact of operating parameters including pressure, peptide concentration and pH of the solution on performance of two selected membranes. Finally, the coupling of UF and NF steps was investigated for the fractionation of a raw hydrolysate prepared from tuna by-products. Three different operation modes coupling UF and NF steps in batch and diafiltration configurations were tested. A fraction rich in peptides of molar mass between 1 and 4 kg mol −1 was isolated and the positive effect of diafiltration on peptide purification process was underlined.

International audience

In this study, the performance of immobilised laccase (Trametes versicolor) was investigated in combination with the mediator syringaldehyde (SYR) in removing a mixture of 38 antibiotics in an enzymatic membrane reactor (EMR). Antibiotics were spiked in osmosed water at concentrations of 10μg·L(-1) each. Laccase without mediator did not reduce the load of antibiotics significantly. The addition of SYR enhanced the removal: out of the 38 antibiotics, 32 were degraded by >50% after 24h. In addition to chemical analysis, the samples' toxicity was evaluated in two bioassays (a growth inhibition assay and the Microtox assay). Here, the addition of SYR resulted in a time-dependent increase of toxicity in both bioassays. In cooperation with SYR, laccase effectively removes a broad range of antibiotics. However, this enhanced degradation induces unspecific toxicity. If this issue is resolved, enzymatic treatment may be a valuable addition to existing water treatment technologies.

The present work proposes the design of cascades that integrate ultrafiltration (UF) and nanofiltration (NF) membranes to separate the different protein fractions from the protein hydrolysate obtained after hydrolysis of tuna byproducts. Experimental data (permeate flux and rejection of protein fractions under different applied pressures) previously obtained and published by this research group were fitted to empirical models, which were the basis for a process simulation model. High recovery rates (0.9) in the UF stages implied high process yields by reduced desired fraction losses, while similar recovery rates in the NF stages were required for high product purity. However, the applied pressures were not so influential over the performance of the system. Optimization problems were solved to identify the optimal design and operation conditions to maximize the product purity or the process yield. Maximal purity of the preferred 1-4 kDa fraction (49.3% from 19.0% in feed stream) obtained by the configuration with 3 UF stages and another 3 NF stages implied 2 and 5 bar pressures applied in the UF and NF stages, respectively, while 0.9 was the optimal recovery rate value for all the stages. These maximal purity conditions resulted in 62.6% process yield, defined as the percentage of the 1-4 kDa fraction in the feed stream recovered in the product stream. In addition, multiobjective optimization of the process was also carried out to obtain the Pareto graphs that represent the counterbalance between maximal yields and purities.

Alkanes constitute one of the vastest reserves of raw materials for the production of fine chemicals. This paper focuses on recent advances in alkane biohydroxylation, i.e. the bioactivation of alkanes into their corresponding alcohols. Enzyme and whole-cell biocatalysts have been reviewed. Process considerations to implement such biocatalysts in bioreactors at large scale by coupling the bioconversion with cofactor regeneration and product removal are also discussed.

A quasi-total loss of the bacterial hydroxylating activity was identified to be responsible for methanol production stop. Different strategies acting on the reaction mixture were implemented to apprehend the biocatalyst behavior in view to extend methanol production. Activity monitoring showed first that sodium formate addition did not maintain the biocatalyst activity and even disrupted bacterial equilibrium when added into the reaction mixture with still active biocatalysts. Reaction medium renewals had no influence on methanol production and highlighted a limited hydroxylating potential of the biocatalyst while addition of fresh biocatalysts in the reaction mixture resulted in methanol consumption. Finally, performing hydroxylation directly in the native bacterial culture appeared as a way to enhance methanol production by both release of intracellular methanol accumulated in the cells during cultivation and effective production by methane hydroxylation.

Osmotic evaporation (OE) is a membrane contactor process which can be used to concentrate aqueous solutions with minimal thermal or mechanical damage. Generally OE is carried out with hydrophobic polymeric membranes, but these membranes can be easily deformed under operating conditions causing the wetting of the pores. In this study we modify the surface of tubular ceramic membranes in order to be used in OE process. Flat and tubular ceramic macroporous alumina membranes with 2×10-7 m of mean pore size were modified by grafting with fluoroalkylsilane. Scanning electron microscopy, mercury porosimetry, contact angle measurements and water penetration pressure (WPP) were used to characterize the porous structure and the hydrophobicity of grafted membranes. The resistance of the hydrophobic layer to cleaning agents (1% NaOH, 1% HNO3, 1% Ultrasil-10, 200 ppm Cl-1 and vapour sterilization) was evaluated by WPP and the performance in OE process was measured after each cycle of cleaning. The cleaning with 1% NaOH and 1% Ultrasil-10 produced a reduction of 15 and 21% of the WPP, respectively. Indeed, the membranes can be used in the OE process while the WPP is higher than the transmembrane pressure applied. © 2006 Elsevier B.V. All rights reserved.

The juice of noni fruit (Morinda citrifolia L.) is claimed to be a natural functional beverage with a growing market both in the USA and Europe. It is traditionally produced by keeping harvested fruit in closed containers for several weeks as the fruit senesces or ages. Little is known about the changes that occur in the juice's microbiological, physicochemical, and functional characteristics during this treatment. Traditional processing was simulated in the laboratory, with samples being recovered and analyzed at various time intervals. At first, fermentation occurred and populations of molds, yeasts, and mesophilic bacteria increased significantly. After 2 weeks, microbial growth changed abruptly, stopping for yeasts, molds, and mesophilic bacteria, and decreasing suddenly for lactic bacteria. Analyses of pH, soluble solids, ethanol, and lactic acid in the fruits confirmed the microbial analyses, indicating initial sensitive variations, followed by values remaining comparatively steady during aging. Vitamin C and total phenol contents also remained constant at 300 ± 60 mg and 50 ± 20 mg GAE, respectively, per 100 g of pulp. Antioxidant capacity likewise remained relatively high at 8 ± 1.5 µmol Trolox  g −1 . All phenolic compounds, including scopoletin and rutin, varied significantly immediately after harvest but remained more or less steady during aging.  2007 Society of Chemical Industry

A new technology based on laccase immobilized over ceramic membranes was formerly developed for the degradation of antibiotics from wastewaters. This work has been pointed to the determination of the economic aspects of this new enzymatic decontamination technology. These calculations have been based on previous modeling and simulations of real scale processes for tetracycline degradation in municipal, hospital and industrial WWTP effluents. A mathematical cost estimation model, originally developed for petrochemical wastewater treatment by ceramic membranes, has been adapted for the proposed enzymatic technology and applied to the subsequent economic viability analysis of the different designed processes in order to determine the competitiveness of this new technology compared to alternative decontamination technologies. Finally, some aspects where the new investigation efforts should be focused on to improve the process competitiveness and overcome the identified economic drawbacks have been proposed. Multi-objective optimization tools were employed to determine the magnitude of the required improvements in three main reactor characteristics: enzymatic kinetics, reactor effective lifetime, and membrane conditioning or regeneration costs. Under these improved conditions, the technology could be considered as a competitive alternative with specific total costs around 1 €/m3.

In this work we studied the synthesis of butyl acetate in an enzymatic packed bed reactor using lipase B, from Candida antarctica , immobilized by simple physical adsorption on porous pellets. The enzymatic reaction was carried out in two different solvents: a conventional organic solvent (n-hexane) and a green solvent (supercritical carbon dioxide). The highest ester productivity in hexane ( 119 μ mol min − 1 g pellets − 1 ) was reached at 323 K, whereas in supercritical CO 2 , a maximum productivity of 501 μ mol min − 1 g pellets − 1 was achieved at 333 K and under 12 MPa. The environmental impacts of each process were estimated by means of the E -factor (mass ratio of amount of waste produced divided by amount of desired product) and the values obtained under the previous conditions were 28.7 and 12.0 respectively. Results show that replacing hexane by supercritical CO 2 in a continuous process increases ester productivity and reduces environmental impact, thus allowing making a more environmentally friendly process.

Several active membranes were prepared by immobilization of Candida antarctica lipase B (CALB) onto the surface of ceramic membranes via three different ionic liquids (ILs): [bmim + ][PF 6 − ], [emim + ][NTf 2 − ] and [bmim + ][NTf 2 − ] and compared to an active membrane obtained by simple enzyme adsorption. The performances of these various membranes were evaluated by studying the synthesis of butyl laurate by the acidolysis between butyl acetate and lauric acid in a hexane/water mixture (98:2, v/v). The results obtained show that all the membranes prepared with or without ILs were active and maintained their activity after several runs and during some months.

The enzymatic membrane reactor (EMR) consists on a coupling of a membrane separation process with an enzymatic reaction. The selective membrane aims to separate the biocatalyst from the reaction products. The main objective of EMR is to ensure the complete rejection of the enzyme in order to maintain the full activity inside the reacting volume. Depending on the case, enzyme molecules may be freely circulating on the retentate side or immobilised onto the membrane surface or inside its porous structure. This article intends to report some significant information showing the last progress realised in the knowledge of the phenomena which limit the performances of EMR, and to mention openings towards new and more efficient systems. A special attention is also paid to new catalytic membrane devices that could result in improved enzyme stability and high performance particularly in non-conventional solvents. © 2004 Elsevier B.V. All rights reserved.