Manuel Rendueles

Effect of processing on functional properties of animal blood plasma

A number of functional and physical properties such as solubility, foam capacity, emulsifying stability and interfacial tension were compared for standard plasma, plasma decationed by ion exchange and plasma deionized by ultrafiltration (UF). The changes in functional properties can determine the use of a protein as an additive to a food product or invalidate its use. All samples had good functional properties and hence could be used in the formulation of food products. Results showed that ion exchange and UF improved emulsifying capacity while having little effect on the other functional properties.

Efficient lactobionic acid production from whey by Pseudomonas taetrolens under pH-shift conditions.

Lactobionic acid finds applications in the fields of pharmaceuticals, cosmetics and medicine. The production of lactobionic acid from whey by Pseudomonas taetrolens was studied in shake-flasks and in a bioreactor. Shake-flask experiments showed that lactobionic acid was a non-growth associated product. A two-stage pH-shift bioconversion strategy with a pH-uncontrolled above 6.5 during the growth phase and maintained at 6.5 during cumulative production was adopted in bioreactor batch cultures. An inoculation level of 30% promoted high cell culture densities that triggered lactobionic acid production at a rate of 1.12 g/Lh. This methodology displayed efficient bioconversion with cheese whey as an inexpensive substrate for lactobionic acid production.

Coupling process for plasma protein fractionation using ethanol precipitation and ion exchange chromatography

Blood is one of the most polluting by-products of the meat industries. Technologies have been developed to recover the proteins contained in blood, and in this study, a process coupling chemical precipitation with ion exchange chromatography was developed to separate and purify the main protein fractions of blood plasma. Ethanol was used as the agent for precipitation and Q-HyperD was used to purify the proteins by chromatography. To monitor all the steps and operations, analytical methods of electrophoresis and HPLC were stablished to identify the fractionated proteins. The results show that this process can recover the main plasma proteins with a high degree of purity for use in the pharmaceutical and food industries.

Bio-production of lactobionic acid: Current status, applications and future prospects

Lactobionic acid has appeared on the commercial scene as a versatile polyhydroxy acid with numerous promising applications in the food, medicine, pharmaceutical, cosmetics and chemical industries. This high value-added bio-product has recently received growing attention as a bioactive compound, providing an excellent chemical platform for the synthesis of novel potentially biocompatible and biodegradable drug delivery vehicles. Recent advances in tissue engineering and nanomedicine have also underlined the increased importance of this organic acid as a key biofunctionalization agent. The growing commercial relevance of lactobionic acid has therefore prompted the development of novel systems for its biotechnological production that are both sustainable and efficient. The present review explores recent advances and studies related to lactobionic acid bio-production, whether through microbial or enzymatic approaches, highlighting the key bioprocessing conditions for enhanced bio-production. Detailed overviews of the current microbial cell factories as well as downstream processing methodologies for lactobionic acid production are also presented. Furthermore, the potential prospects and current applications of this polyhydroxy acid are also discussed, with an emphasis on the role of lactobionic acid as a key platform in the development of novel drugs, biomaterials, nanoparticles and biopolymer systems.

Demineralization of animal blood plasma by ion exchange and ultrafiltration.

The blood waste from slaughterhouses is strictly controlled due to its high pollutant load, the treatment for its purification being of great economic interest. The separation of proteins, the most valuable components of blood, in a chromatographic column requires the use of well treated plasma, in particular the removal of inorganic salts. Accordingly, a demineralization process is usually required. In this paper, ion exchange and ultrafiltration demineralization techniques were tested and the results compared. In the ion exchange experiments, the blood plasma was treated with cationic and anionic resins in packed columns, studying the removal of the major cations and anions, protein loss and pH evolution in both the loading and elution steps. In the demineralization process by means of membranes, a 10KDa ultrafiltration membrane was used, the blood plasma being filtered to concentrate all the proteins in the retentate while removing the inorganic ions and other compounds in the permeate. The evolution of the major anions and cations in the plasma and the protein loss were studied at different volumetric concentration factors. The results obtained enable us to draw conclusions as regards the advantages and disadvantages of each technique at a laboratory scale and to offer some considerations regarding the operation at an industrial scale.

Straining phenomena in bacteria transport through natural porous media

Background, aim, and scopeTransport of bacteria through natural porous media is an issue of increasing concern arising in several very important environmental processes. These include the percolation of bacteria from fecal waste to drinking water reservoirs, thus leading to a risk for human health, or the bioremediation of contaminated soils in which the bacteria are expected to travel long distances underground in order to reach contaminated areas and degrade chemicals originating from accidental spills. An understanding of bacterial retention and transport mechanisms in porous media would be of great help in the development of models able to predict the distance covered by bacterial suspensions in these situations.Materials and methodsExperiments were carried out preparing columns filled of soil and sand, introducing bacteria culture (Escherichia coli, Pseudomona putida, and Listeria innocua) solutions by the top of the column. Breakthrough curves were obtained to see the transport of the bacteria in the column.ResultsThe transport of different bacteria in the two soils aimed at establishing the relative importance of straining in different conditions. This has enabled us to obtain certain parameters, such as the sticking coefficients derived from the filtration theory or bacterial recoveries after multi-step elution, which aid our understanding of how bacteria are retained by mechanisms different to those usually included in the physico-chemical filtration theory.DiscussionSeveral indicators may be used to determine the degree of relevance of straining as a mechanism acting during bacterial transport through porous media. Usually, in natural media, neither straining nor physico-chemical filtration is the sole mechanism contributing to bacterial retention. The retention of bacteria by straining mechanisms can be assessed by means of elution profiles under varying conditions. The inversion of flow in our experiments gave rise to secondary elution peaks, probably originating from bacteria retained in narrow poresConclusionsAccording to experimental observations, straining was shown to contribute highly to bacterial retention in all the soils tested, in particular in the soils with a broader grain size distribution and more irregular shape. In both media, an increase in ionic strength did not lead to significant differences in bacterial retention, possibly due to the lack of relevance of ionic repulsion as a barrier to physico-chemical attachment of particlesRecommendation and perspectivesThe study of bacteria transport in natural soil is an important step in the development of decontamination processes. The importance of the straining in the transport process has been revealed in the work carried out in this paper.

Microbial production of specialty organic acids from renewable and waste materials

Abstract Microbial production of organic acids has become a fast-moving field due to the increasing role of these compounds as platform chemicals. In recent years, the portfolio of specialty fermentation-derived carboxylic acids has increased considerably, including the production of glyceric, glucaric, succinic, butyric, xylonic, fumaric, malic, itaconic, lactobionic, propionic and adipic acid through innovative fermentation strategies. This review summarizes recent trends in the use of novel microbial platforms as well as renewable and waste materials for efficient and cost-effective bio-based production of emerging high-value organic acids. Advances in the development of robust and efficient microbial bioprocesses for producing carboxylic acids from low-cost feedstocks are also discussed. The industrial market scenario is also reviewed, including the latest information on the stage of development for producing these emerging bio-products via large-scale fermentation.

Role of dissolved oxygen availability on lactobionic acid production from whey by Pseudomonas taetrolens.

The influence of dissolved oxygen availability on cell growth and lactobionic acid production from whey by Pseudomonas taetrolens has been investigated for the first time. Results from pH-shift bioreactor cultivations have shown that high agitation rate schemes stimulated cell growth, increased pH-shift values and the oxygen uptake rate by cells, whereas lactobionic acid production was negatively affected. Conversely, higher aeration rates than 1.5 Lpm neither stimulated cell growth nor lactobionic acid production (22% lower for an aeration rate of 2 Lpm). Overall insights into bioprocess performance enabled the implementation of 350 rpm as the optimal agitation strategy during cultivation, which increased lactobionic productivity 1.2-fold (0.58-0.7 g/Lh) compared to that achieved at 1000 rpm. Oxygen supply has been shown to be a key bioprocess parameter for enhanced overall efficiency of the system, representing essential information for the implementation of lactobionic acid production at a large scale.

Uptake of copper and cobalt in a complexing resin: shrinking-core model with two reaction fronts

The kinetics of simultaneous ion exchange of copper and cobalt with iminodiacetic chelating resins has been studied. Microscopic studies of the ion-exchange process clearly show two different reaction fronts allowing the use of shrinking-core type models. The influence of system parameters is studied both theoretically and experimentally. Experimental results obtained at different total ion concentrations for various copper-cobalt ratios and particle diameters are reasonably predicted by the shrinking-core model, allowing diffusivity calculations.

Production of porcine hemoglobin peptides at moderate temperature and medium pressure under a nitrogen stream. Functional and antioxidant properties.

A new hydrolysis method for producing peptides from porcine hemoglobin has been developed. Current processes are based on the use of expensive enzymes or high hydrostatic pressures. In the present study, a cheap and effective process has been assayed to produce peptides from purified porcine hemoglobin. A solution of purified hemoglobin is heated at different temperatures and pressurized at 4 MPa while a stream of nitrogen is injected into the reactor. A total of 82% of initial hemoglobin was transformed into peptides presenting an average size of 3.2 kDa. Some preferential hydrolyzed bonds have been detected. The peptide size distribution was evaluated at different times and temperatures. It has been demonstrated that this technique produces large amounts of peptides possessing good antioxidant properties. Furthermore, functional properties are conserved, and a desirable decrease in color (80%) is achieved.