Zinc, manganese, and copper amino acid complexes improve performance and bone characteristics of layer-type chicks under thermoneutral and cold stress conditions.

Two experiments were designed to evaluate the effect of mineral-amino acid complexes (AACM) as a partial replacement of inorganic mineral (IM) in layer-type chicks' diets. Both studies had the same dietary treatments, where in experiment 1 (Exp. 1) was conducted under thermoneutral conditions from 0 to 35 D and chicks in experiment 2 (Exp. 2) were exposed to cold stress conditions at nighttime during the first 15 D and to thermoneutral condition from 16 to 35 D. For each trial, 1,200 one-day-old Lohmann Brown chicks were used, with 20 cage replicates with 30 chicks per cage. Treatments consisted of the control diet (IM; with 70, 70, and 8 mg/kg of zinc [Zn], manganese [Mn], and copper [Cu], respectively) and the treatment diet (AACM, with 40, 40, and 2.75 mg/kg of Zn, Mn, and Cu, respectively, from IM sources, along with 30, 30, and 5.25 mg/kg of Zn, Mn, and Cu, respectively). Data were submitted to analysis of variance, and means were compared using the t-test (P < 0.05). In Exp. 1, there were no significant differences between treatments on chick performance. However, AACM-fed chicks had higher thymus (P = 0.03) and cecum weight (P < 0.01), superior micromineral deposition in the tibias (P < 0.01), and reduced phosphorus excretion (P = 0.03). In Exp. 2, chicks fed with AACM had higher body weight gain (P = 0.04), better average daily feed intake (P = 0.03), lower phosphorus excretion (P = 0.02), and higher liver and pancreas weight (P < 0.01) in the last week of the study. In conclusion, chicks fed with AACM under thermoneutral conditions had higher bone mineralization and reduced excretion of phosphorus, and in adverse conditions, AACM improves performance and liver and pancreas weight, also reducing phosphorus excretion.

New record of the invasive snail Melanoides tuberculata (Gastropoda, Thiaridae) - Ceará State, Brazil / Novo registro do gastropode invasor Melanoides tuberculata (Gastropoda, Thiaridae) - Estado do Ceará, Brasil

Abstract Melanoides tuberculata is a freshwater gastropod native to Africa and Asia, and currently presents distributed worldwide. The first record of Melanoides tuberculata in South America occurred in Brazil, in the city of Santos, state of São Paulo, in 1967. Therefore, the objective of the present study is to report the occurrence of Melanoides tuberculata for Banana Lagoon and to characterize the current population situation. The gastropods were collected through direct visualization of shells, morphometric measurements of Melanoides tuberculata shells were determined using a digital caliper. After identifying the gastropod and its first distribution in the area, a preliminary descriptive analysis of the population was carried out. The gastropods were classified by grouping the individuals into four classes according to the shell width (mm). This is the first record of the occurrence of Melanoides tuberculata, in Banana Lagoon, Caucaia municipality, Ceará state, Northeast Brazil, being the largest specimen cited in the literature (33.77 mm) and 92.65% of the gastropods present in sizes above the first reproduction stages.

Resumo Melanoides tuberculata é um gastrópode de água doce nativo da África e da Ásia e atualmente apresenta-se distribuído mundialmente. O primeiro registro de Melanoides tuberculata na América do Sul ocorreu no Brasil, na cidade de Santos, estado de São Paulo, em 1967. Portanto, o objetivo do presente estudo é relatar a ocorrência de Melanoides tuberculata para Lagoa do Banana, caracterizando a situação atual da população no local. Os gastrópodes foram coletados através da visualização direta de conchas, e as medidas morfométricas das conchas de Melanoides tuberculata foram determinadas por meio de um paquímetro digital. Após identificar o gastrópode e constando sua primeira distribuição na área, realizou-se uma análise preliminar descritiva da população. Os gastrópodes foram classificados agrupando os indivíduos em quatro classes de acordo com a largura da concha (mm). Este é o primeiro registro da ocorrência de Melanoides tuberculata, na Lagoa da Banana, município de Caucaia, estado do Ceará, Nordeste do Brasil, sendo o maior exemplar citado na literatura (33,77 mm) já registrado e 92,65% dos gastrópodes apresentam-se em tamanhos acima do primeiro estágios de reprodução.

New record of the invasive snail Melanoides tuberculata (Gastropoda, Thiaridae) - Ceará State, Brazil.

Melanoides tuberculata is a freshwater gastropod native to Africa and Asia, and currently presents distributed worldwide. The first record of Melanoides tuberculata in South America occurred in Brazil, in the city of Santos, state of São Paulo, in 1967. Therefore, the objective of the present study is to report the occurrence of Melanoides tuberculata for Banana Lagoon and to characterize the current population situation. The gastropods were collected through direct visualization of shells, morphometric measurements of Melanoides tuberculata shells were determined using a digital caliper. After identifying the gastropod and its first distribution in the area, a preliminary descriptive analysis of the population was carried out. The gastropods were classified by grouping the individuals into four classes according to the shell width (mm). This is the first record of the occurrence of Melanoides tuberculata, in Banana Lagoon, Caucaia municipality, Ceará state, Northeast Brazil, being the largest specimen cited in the literature (33.77 mm) and 92.65% of the gastropods present in sizes above the first reproduction stages.

Aspecto médico veterinário legal das lesões em aves silvestres promovidas por colisões com aeronaves / Medico-legal veterinary aspect of lesions in bird strike

The objective of this study was to describe lesions in four birds, victims of collisions with aircraft, coming from the International Airport of Recife/Guararapes Gilberto Freyre, Pernambuco, Brazil. Contused wounds were predominant in birds in this study, characterized by the presence of fractures, bruises and hematomas and justified by the blunt action promoted by the type of vulnerant agent involved (aircraft). The analysis under medico-legal veterinary aspect of lesions in bird strike is essential, because in addition to the attempt to establish a standard for differentiating the aircraft lesions, it can guide the bird strike hazard management programs at airports, since the necropsy allows the identification of the species involved or at least facilitates the obtaining biological material for identification.(AU)

Determination of partition coefficients of biomolecules in a microfluidic aqueous two phase system platform using fluorescence microscopy.

Aqueous two phase systems (ATPS) offer great potential for selective separation of a wide range of biomolecules by exploring differences in molecular solubility in each of the two immiscible phases. However, ATPS use has been limited due to the difficulty in predicting the behavior of a given biomolecule in the partition environment together with the empirical and time-consuming techniques that are used for the determination of partition and extraction parameters. In this work, a fast and novel technique based on a microfluidic platform and using fluorescence microscopy was developed to determine the partition coefficients of biomolecules in different ATPS. This method consists of using a microfluidic device with a single microchannel and three inlets. In two of the inlets, solutions containing the ATPS forming components were loaded while the third inlet was fed with the FITC tagged biomolecule of interest prepared in milli-Q water. Using fluorescence microscopy, it was possible to follow the location of the FITC-tagged biomolecule and, by simply varying the pumping rates of the solutions, to quickly test a wide variety of ATPS compositions. The ATPS system is allowed 4min for stabilization and fluorescence micrographs are used to determine the partition coefficient.The partition coefficients obtained were shown to be consistent with results from macroscale ATPS partition. This process allows for faster screening of partition coefficients using only a few microliters of material for each ATPS composition and is amenable to automation. The partitioning behavior of several biomolecules with molecular weights (MW) ranging from 5.8 to 150kDa, and isoelectric points (pI) ranging from 4.7 to 6.4 was investigated, as well as the effect of the molecular weight of the polymer ATPS component.

The application of microbeads to microfluidic systems for enhanced detection and purification of biomolecules.

This paper describes microbead-based microfluidic systems. Several aspects of bead assays in microfluidics make them advantageous for bioassays in simple microchannels, including enhanced surface-to-volume ratio, improved molecular recognition reaction efficiency, and the wide range of surface functionalization available with commercial microbeads. Two-level SU-8 molds are used to fabricate PDMS microchannels that can hydrodynamically trap different types of microbeads, with characteristic dimensions of tens of microns. The use of these microbead-based microfluidic systems in the biosensing of antibodies, toxins and nucleic acids, as well as in antibody purification will be presented and discussed in this paper.

A point-of-use microfluidic device with integrated photodetector array for immunoassay multiplexing: Detection of a panel of mycotoxins in multiple samples.

For a point-of-use analytical device to be successful in real-world applications, it needs to be rapid, simple to operate and, ideally, able to multiplex the detection of several analytes and samples. Mycotoxin detection in food and feedstock in particular has become increasingly relevant as these toxins, such as ochratoxin A (OTA), aflatoxin B1 (AFB1) and deoxynivalenol (DON), are subject to strict regulations and recommendations in the European Union. A novel, simple, negative pressure-driven device with manually operated magnetic valves was developed and the simultaneous immunodetection of these three mycotoxins was demonstrated via the laminar flow patterning of probes in an area of ≈0.12mm2 and subsequent chemiluminescence generation via HRP-labeled antibodies. The three mycotoxins were detected in less than 20min at concentrations of 100ng/mL for OTA and DON and 3ng/mL for AFB1, spiked in a sample under analysis and simultaneously compared to a toxin-free reference and a standard contaminated with critical target concentrations. The on-chip optical detection was performed in a single acquisition step by integrating a microfabricated array of 25×25µm2 hydrogenated amorphous silicon (a-Si:H) photosensors below the microfluidic chip. The device presented in this work is simple and effective for point-of-use multiplexing of immunoassays and was applied in this work to the screening of mycotoxins.

New record of the invasive snail Melanoides tuberculata (Gastropoda, Thiaridae) - Ceará State, Brazil

Abstract Melanoides tuberculata is a freshwater gastropod native to Africa and Asia, and currently presents distributed worldwide. The first record of Melanoides tuberculata in South America occurred in Brazil, in the city of Santos, state of São Paulo, in 1967. Therefore, the objective of the present study is to report the occurrence of Melanoides tuberculata for Banana Lagoon and to characterize the current population situation. The gastropods were collected through direct visualization of shells, morphometric measurements of Melanoides tuberculata shells were determined using a digital caliper. After identifying the gastropod and its first distribution in the area, a preliminary descriptive analysis of the population was carried out. The gastropods were classified by grouping the individuals into four classes according to the shell width (mm). This is the first record of the occurrence of Melanoides tuberculata, in Banana Lagoon, Caucaia municipality, Ceará state, Northeast Brazil, being the largest specimen cited in the literature (33.77 mm) and 92.65% of the gastropods present in sizes above the first reproduction stages.

Resumo Melanoides tuberculata é um gastrópode de água doce nativo da África e da Ásia e atualmente apresenta-se distribuído mundialmente. O primeiro registro de Melanoides tuberculata na América do Sul ocorreu no Brasil, na cidade de Santos, estado de São Paulo, em 1967. Portanto, o objetivo do presente estudo é relatar a ocorrência de Melanoides tuberculata para Lagoa do Banana, caracterizando a situação atual da população no local. Os gastrópodes foram coletados através da visualização direta de conchas, e as medidas morfométricas das conchas de Melanoides tuberculata foram determinadas por meio de um paquímetro digital. Após identificar o gastrópode e constando sua primeira distribuição na área, realizou-se uma análise preliminar descritiva da população. Os gastrópodes foram classificados agrupando os indivíduos em quatro classes de acordo com a largura da concha (mm). Este é o primeiro registro da ocorrência de Melanoides tuberculata, na Lagoa da Banana, município de Caucaia, estado do Ceará, Nordeste do Brasil, sendo o maior exemplar citado na literatura (33,77 mm) já registrado e 92,65% dos gastrópodes apresentam-se em tamanhos acima do primeiro estágios de reprodução.

Determination of aqueous two phase system binodal curves using a microfluidic device.

Aqueous two phase systems (ATPS) offer great potential for selective separation of a wide range of biomolecules by exploring differences in solubility in each of the two phases. However, their use has been greatly hindered due to poor theoretical understanding of the principles behind ATPS formation and the empirical and time-consuming techniques used for the determination of optimal extraction parameters including the binodal curves. In this work, characteristic ATPS binodal curves were determined by a novel technique in which the formation of an ATPS system is measured in a microfluidic device. Two solutions containing separate ATPS solution precursors were loaded into the side inlets of a three inlet microfluidic channel while milli-Q water was loaded into the middle inlet. By varying the flow rates of the three solutions, a wide range of concentrations inside the microchannel could be rapidly tested using limited volumes. Using optical microscopy, depending on the concentrations inside the microchannel, three different states could be observed at the end of the microchannel (i) the presence of an interface; (ii) no presence of an interface; or (iii) the presence of an unstable interface. The binodal curve was calculated using the points corresponding to unstable interfaces and compared to binodal curves obtained through the standard turbidometric titration method for both PEG/salt and PEG/dextran systems.

On-chip sample preparation and analyte quantification using a microfluidic aqueous two-phase extraction coupled with an immunoassay.

Immunoassays are fast and sensitive techniques for analyte quantification, and their use in point-of-care devices for medical, environmental, and food safety applications has potential benefits of cost, portability, and multiplexing. However, immunoassays are often affected by matrix interference effects, requiring the use of complex laboratory extraction and concentration procedures in order to achieve the required sensitivity. In this paper we propose an integrated microfluidic device for the simultaneous matrix clean-up, concentration and detection. This device consists of two modules in series, the first performing an aqueous two-phase extraction (ATPE) for matrix extraction and analyte pre-concentration, and the second an immunoassay for quantification. The model analyte was the mycotoxin ochratoxin A (OTA) in a wine matrix. Using this strategy, a limit of detection (LoD) of 0.26 ng mL(-1) was obtained for red wine spiked with OTA, well below the regulatory limit for OTA in wines of 2 ng mL(-1) set by the European Union. Furthermore, the linear response on the logarithmic concentration scale was observed to span 3 orders of magnitude (0.1-100 ng mL(-1)). These results are comparable to those obtained for the quantification of OTA in plain buffer without an integrated ATPE (LoD = 0.15 ng mL(-1)). The proposed method was also found to provide similar results for markedly different matrices, such as red and white wines. This novel approach based on aqueous two-phase systems can help the development of point-of-care devices that can directly deal with real samples in complex matrices without the need for extra extraction processes and equipment.

Aqueous two-phase systems for enhancing immunoassay sensitivity: simultaneous concentration of mycotoxins and neutralization of matrix interference.

Immunoassays have a broad application range, from environmental and food toxicology to biomedical analysis, providing rapid and simple methods for analyte quantification. Immunoassays, however, are often challenging at nM and sub nM concentrations and are affected by detrimental matrix interference effects, as is the case of the detection of ochratoxin A (OTA) and Aflatoxin B1 (AFB1). These are widespread mycotoxins found in food and feed, with serious potential implications for human health. This work demonstrates the use of polymer-salt aqueous two phase systems (ATPSs) for the simultaneous concentration of mycotoxins and neutralization of matrix interference. In particular, polyethylene glycol (PEG)-phosphate salt ATPSs were used to enhance the detection sensitivity of OTA and AFB1 in wines and beer by an indirect competitive ELISA. Using this methodology it was possible to quantify both analytes spiked in red wine with limits-of-detection (LoD) down to 0.19 ng/mL and 0.035 ng/mL, respectively, with results comparable to those obtained using solutions of toxins in phosphate buffered saline (PBS) buffer (0.7 ng/mL and 0.009 ng/mL, respectively). Furthermore, a very low matrix-to matrix variability was observed, with LoD and half inhibitory concentration (IC50) values of 5.17 ± 1.08 and 33.2 ± 3.5 ng/mL (±SD) obtained in the detection of OTA spiked in red and white wines, beer or PBS buffer. These results indicate the potential of ATPS as a fast and simple concentration step and in providing matrix-independent analyte quantification for enhanced immunoassay sensitivity below regulatory levels.

Magnetic separations in biotechnology.

Magnetic separations are probably one of the most versatile separation processes in biotechnology as they are able to purify cells, viruses, proteins and nucleic acids directly from crude samples. The fast and gentle process in combination with its easy scale-up and automation provide unique advantages over other separation techniques. In the midst of this process are the magnetic adsorbents tailored for the envisioned target and whose complex synthesis spans over multiple fields of science. In this context, this article reviews both the synthesis and tailoring of magnetic adsorbents for bioseparations as well as their ultimate application.

Carotenoid and lipid production by the autotrophic microalga Chlorella protothecoides under nutritional, salinity, and luminosity stress conditions.

Today microalgae represent a viable alternative source for high-value products. The specie Chlorella protothecoides (Cp), heterotrophically grown, has been widely studied and provides a high amount of lutein and fatty acids (FA) and has a good profile for biodiesel production. This work studies carotenoid and FA production by autotrophic grown Cp. Cp was grown until the medium's nitrogen was depleted, then diluted in NaCl solution, resulting in nutritional, luminosity, and salinity stresses. Different NaCl concentrations were tested (10, 20, 30 g/L) at two different dilutions. After dilution, a color shifting from green to orange-red was noticed, showing carotenoid production. The best production of both carotenoids and FA was attained with a 20 g/L NaCl solution. The total carotenoid content was 0.8 % w/w (canthaxanthin (23.3 %), echinenone (14.7 %), free astaxanthin (7.1 %), and lutein/zeaxanthin (4.1 %)). Furthermore, the total lipid content reached 43.4 % w/w, with a FA composition of C18:1 (33.64 %), C16:0 (23.30 %), C18:2 (11.53 %), and less than 12 % of C18:3, which is needed to fulfill the biodiesel quality specifications (EN 14214).

Fishing human monoclonal antibodies from a CHO cell supernatant with boronic acid magnetic particles.

In this work we have evaluated the potential of boronic acid functionalized magnetic particles for the one-step capture of a human monoclonal antibody (mAb) from a Chinese hamster ovary (CHO) cell culture supernatant. For comparison, Protein A coated magnetic particles were also used. The most important factor influencing the overall process yield and product purity in boronic acid particles was found to be the binding pH. Basic pH values promoted higher purities while resulting in decreased yields due to the competing effects of molecules such as glucose and lactate present in the cell culture supernatant. After optimization, the particles were successfully used in a multi-cycle purification process of the mAb from the CHO feedstock. Boronic acid particles were able to achieve an average overall yield of 86% with 88% removal of CHO host cell proteins (HCP) when the binding was performed at pH 7.4, while at pH 8.5 these values were 58% and 97%, respectively. In both cases, genomic DNA removal was in excess of 97%. Comparatively, Protein A particles recorded an average overall yield of 80% and an HCP removal greater than 99%. The adsorption of the mAb to the boronic acid particles was shown to be mediated by strong affinity interactions. Overall, boronic acid based purification processes can offer a cost-effective alternative to Protein A as the direct capturing step from the mammalian cell culture.

Design of a microfluidic platform for monoclonal antibody extraction using an aqueous two-phase system.

The use of monoclonal antibodies (mAbs) in medical treatments and in laboratory techniques has a very important impact in the battle against many diseases, namely in the treatment of cancer, autoimmune diseases and neural disorders. Thus these biopharmaceuticals have become increasingly important, reinforcing the demand for efficient, scalable and cost-effective techniques for providing pure antibodies. Aqueous two-phase systems (ATPS) have shown potential for downstream processing of mAbs. In this work, an ATPS in a microfluidic platform was designed and tested for mAbs extraction. The system demonstrated the potential to be an effective tool to accelerate bioprocess design and optimization. The partition of immunoglobulin G (IgG) tagged with fluorescein isothiocyanate (FITC) in an ATPS of polyethylene-glycol (PEG)/phosphate buffer with NaCl was investigated using a PDMS microfluidic device fabricated using soft lithography techniques. Different structures were tested with different values of microchannel length (3.14-16.8 cm) and flow rates of the salt (1-2 µL/min) and PEG-rich phases (0.2-0.5 µL/min). A stable interphase between the phases was obtained and the phenomena of diffusion and of partition of the IgG from the salt-rich phase to the PEG-rich phase were measured by fluorescence microscopy. Process simulation allowed the modeling of the IgG diffusion and partitioning behavior observed in the microstructure. The reduction to the microscale does not greatly affect the antibody extraction yield when compared with macroscale results, but it does reduce the operation time, demonstrating the potentiality of this approach to process optimization.

Continuous aqueous two-phase extraction of human antibodies using a packed column.

The performance of a pilot scale packed differential contactor was evaluated for the continuous counter-current aqueous two-phase extraction (ATPE) of human immunoglobulin G (IgG) from a Chinese hamster ovary (CHO) cells supernatant (CS) enriched with pure protein. Preliminary studies have been firstly performed in order to select the dispersed phase (phosphate-rich or polyethylene glycol 3350 Da (PEG)-rich phase) and the column packing material. The PEG-rich phase has been selected as the dispersed phase and the stainless steel as the preferred material for the column packing bed since it was not wetted preferentially by the selected dispersed phase. Hydrodynamic studies have been also performed, and the experimental results were successfully adjusted to the Richardson-Zaki and Mísek equations, typically used for the conventional organic-aqueous two-phase systems. An experimental set-up combining the packed column with a pump mixer-settler stage showed to have the best performance and to be advantageous when compared to the IgG batch extraction. An IgG recovery yield of 85% could be obtained with about 50% of total contaminants and more than 85% of contaminant proteins removal. Mass transfer studies have revealed that the mass transfer was controlled by the PEG-rich phase. A higher efficiency could be obtained when using an extra pump mixer-settler stage and higher flow rates.

Potential of boronic acid functionalized magnetic particles in the adsorption of human antibodies under mammalian cell culture conditions.

In this work, we systematically evaluated the potential of using boronic acid functionalized magnetic particles in the capturing of human immunoglobulin G under typical mammalian cell culture conditions. For comparison, Protein A coated magnetic particles were also used. The binding pH was found to significantly influence the adsorption isotherms of boronic acid particles with the higher capacities (0.216 g IgG/g support) being observed at pH 7.4. Comparatively, this value was 0.109 g IgG/g support, for Protein A particles under the same conditions. Both particles revealed very fast adsorption kinetics with more than 70% of the maximum binding capacity being achieved in a few seconds. The effect of glucose and lactate, which are known to interact with boronic acid, was evaluated. For glucose, the binding capacity was significantly influenced by the pH and decreased as pH increased. At pH 9.5, a 70% lower binding capacity was observed for glucose concentrations as low as 0.5 g/l. The effect of lactate was less pronounced and almost pH independent reaching at most 20% decrease in binding capacity. Nevertheless, the effect of both molecules was always lower at pH 7.4. The optimization of the elution conditions enabled complete recovery of bound IgG from boronic acid particles using 50mM Tris-HCl, 200 mM sorbitol, 200 mM NaCl at pH 8.5.

Aqueous two-phase extraction as a platform in the biomanufacturing industry: economical and environmental sustainability.

The biotech industry is, nowadays, facing unparalleled challenges due to the enhanced demand for biotechnology-based human therapeutic products, such as monoclonal antibodies (mAbs). This has led companies to improve substantially their upstream processes, with the yield of monoclonals increasing to titers never seen before. The downstream processes have, however, been overlooked, leading to a production bottleneck. Although chromatography remains the workhorse of most purification processes, several limitations, such as low capacity, scale-related packing problems, low chemical and proteolytic stability and resins' high cost, have arisen. Aqueous two-phase extraction (ATPE) has been successfully revisited as a valuable alternative for the capture of antibodies. One of the important remaining questions for this technology to be adopted by the biotech industries is, now, how it compares to the currently established platforms in terms of costs and environmental impact. In this report, the economical and environmental sustainability of the aqueous two-phase extraction process is evaluated and compared to the currently established protein A affinity chromatography. Accordingly, the ATPE process was shown to be considerably advantageous in terms of process economics, especially when processing high titer cell culture supernatants. This alternative process is able to purify continuously the same amount of mAbs reducing the annual operating costs from 14.4 to 8.5 million (US$/kg) when cell culture supernatants with mAb titers higher than 2.5 g/L are processed.

Minimal state tomography of spatial qubits using a spatial light modulator.

We report minimal quantum state tomography with spatial qubits created by a pair of parametric down converted twin-photons passing through a double-slit. A novel experimental setup is used, which includes a Spatial Light Modulator, as a fundamental tool, to reconstruct the state density matrix. The theory needed to perform a minimal quantum tomography is described. The density matrix is experimentally obtained for the two-qubit photonic states in spatial variables.

Capture of human monoclonal antibodies from a clarified cell culture supernatant by phenyl boronate chromatography.

In this work, we investigated the feasibility of using phenyl boronate (PB) chromatography for the direct capture of monoclonal antibodies from a CHO cell supernatant. Preliminary results, using pure protein solutions have shown that PB media can bind to human antibodies, not only at strong alkaline conditions but also at acidic pH values. In fact, antibodies have been found to bind in the pH range 5.5-8.5. On the other hand, insulin and human serum albumin did not bind at alkaline pH but at lower pH, which reflects the importance of non-specific interactions with the matrix. Different binding and eluting buffers were evaluated for the capture of immunoglobulin G (IgG) from a CHO cell supernatant and the most promising results were obtained using 20 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid at pH 8.5 as binding buffer and 1.5 M Tris-HCl as eluting buffer. Using a step elution, all IgG was recovered in the elution pool with a maximum purification factor of 56. A gradient elution allowed a further increase of the final purity, yet achieving a slightly lower yield. IgG recovery was around 85% and the purification factor was 76. The highest purity was obtained when the pH of the cell supernatant feed was previously adjusted to 8.5. Starting from an initial protein purity of 1.1% and high-performance liquid chromatography (HPLC) purity of 2.2%, after PB adsorption, a final protein purity of 85% and a HPLC purity of 88% was achieved.