There has been much interest generated in the recovery of nanoparticulate (nanoparticle) bioproducts (Second generation of biotechnological products) such as plasmid DNA and viruses as putative gene therapy vectors, macromolecular assemblies as drug delivery vehicles and virus-like particles as vaccine components. Such product must be manufactured in advanced stages of purity, material definition and sophisticated formulation to rival those demanded of the pharmaceutical macromolecules which dominate as the first generation products. Nanoparticulates are characterized by a critical size range (10-300 nm diameter) and complexity of surface chemistry and internal organisation which pose new challenges in separation science and engineering, controlled chemistries of modification and material measurement not readily addressed by extant technologies. Current review article is concerns with structural characterisations of nanoparticulate bioproducts as well as redesign of their downstream processing techniques which are common to all programmes. This focus is upon candidate partition systems which can contribute to the fractionation, recovery and purification of nanoparticulate assemblies from their soluble components (capsid proteins from virus, polynucleotides from plasmid DNA, soluble, agglomerated forms of protein etc.). The mechanistic design of new separation and formulation technologies based upon a sound understanding of quantifiable structural features of these nanoparticle bioproducts is strongly indicated.

Production of human proteins in Pichia pastoris has significant advantages. However, there is still need for improvement of various stages of its downstream processing like clarification and purification. In fact downstream processes are usually the most critical part of production of biotech products. This work aimed to evaluate the effect of two steps added to the downstream processes of human growth hormone (hGH) production in Pichia pastoris. Firstly, the effect of clarification, with activated carbon, on capture of hGH by ion exchange chromatography (IEC) was investigated. For this purpose, a clarification process using activated carbon was used to remove process contaminants like pigments. The clarified sample was applied to the IEC column and the recovery of hGH, following IEC, was assessed using SDS-PAGE, Bradford protein assay, and area under the curve (AUC). The obtained results showed that the AUC values were 2. 81 and 5. 61 for the with-and without-treatment samples, respectively. Protein recovery of clarified sample with activated carbon was 541 mg in comparison with 328 mg for the sample without treatment. The yield of IEC was also improved from 50. 46% to 83. 23% following treatment with activated carbon. Secondly, the effect of three concentrations of ammonium sulfate in the binding buffer on resolution of hGH upon elution on hydrophobic interaction chromatography (HIC) was investigated. Biological activity was used as the main criterion for evaluation of purified hGH using HIC. The obtained results indicated that by increasing the concentration of ammonium sulfate form 1 to 3 mol/L, resolution of hGH was improved, as the purified fraction using 3 mol/L of ammonium sulfate showed a specific activity of 3. 1IU/mg. So, the results of the present study demonstrated that activated carbon is a promising candidate for efficient clarification of recombinant hGH and for improving the efficiency of the capture step. Therefore, it can be considered by biotech companies as a cost-effective and sustainable clarification procedure of recombinant proteins from high cell density cultures. This study also revealed that 3% ammonium sulfate has a positive effect on the separation of hGH variants with the desired biological activity.

Newcastle disease virus from the Paramyxoviridae family is a single-stranded negative-sense RNA virus. NDV is an infection of domestic poultry and nearly all bird species. It has been a very severe difficulty for the poultry industry all over the world Even though it remains a potential threat to poultry industries, this virus is a powerful oncolytic virus as well. In this study a process was accomplished to achieve concentrated and highly purified NDV V4 strain particles. Downstream processing of Newcastle virus strain V4 was characterized by amplifying virus in embryonated chicken eggs. Through a sequence of steps, harvesting allantoic fluid, clarification by centrifuge, concentration by ultrafiltration, size exclusion separation, the reduced volume and pure virus particles were considered for the amount of ovalbumin, hemagglutinin activity, electron microscopy (TEM), electrophoresis, and additionally immunogenicity of prepared antigens. The results presented a high recovery of HA activity in concentrated and pure virus with removing of ovalbumin and the typical morphology based on TEM. Sepharose CL-4B was determined as the best media among all used resins to purify the virus. Prepared formulations as vaccines demonstrated a positive hemagglutinin inhibition for 6 months duration and stable for two years. Organized study provided strong evidence that this method was quite appropriate in concentrating and purifying of intact Newcastle disease virus to use in vaccine research, also in antiserum preparation, or probably like an oncotic agent as an alternative to conventional procedures. Though additional studies are being tested, this procedure can be used practically on a semi-industrial scale in the production of multiple vaccine components.