Biological product recovery

A membrane filter which can uniformly remove all viral agents regardless of the size of the viral agent is not available. Part of the difficulty is that the efficient recovery of the biological product diminishes as the size difference between the vims and biological product lessens. Thus a balance needs to be met where vims removal and product recovery are optimized. 

Albertsson (Paiiition of Cell Paiiicle.s and Macromolecules, 3d ed., Wiley, New York, 1986) has extensively used particle distribution to fractionate mixtures of biological products. In order to demonstrate the versatility of particle distribution, he has cited the example shown in Table 22-14. The feed mixture consisted of polystyrene particles, red blood cells, starch, and cellulose. Liquid-liquid particle distribution has also been studied by using mineral-matter particles (average diameter = 5.5 Im) extracted from a coal liquid as the solid in a xylene-water system [Prudich and Heniy, Am. Inst. Chem. Eng. J., 24(5), 788 (1978)]. By using surface-active agents in order to enhance the water wettability of the solid particles, recoveries of better than 95 percent of the particles to the water phase were obsei ved. All particles remained in the xylene when no surfactant was added. 

Initially fermentation broth has to be characterised on the viscosity of the fluid. If the presence of the biomass or cells causes trouble, they have to be removed. Tire product is stored inside the cells, the cells must be ruptured and the product must be freed. Intracellular protein can easily be precipitated, settled or filtered. In fact the product in diluted broth may not be economical enough for efficient recovery. Enrichment of the product from the bioreactor effluents for increasing product concentration may reduce the cost of product recovery. There are several economical methods for pure product recovery, such as crystallisation of the product from the concentrated broth or liquid phase. Even small amounts of cellular proteins can be lyophilised or dried from crude solution of biological products such as hormone or enzymes.2,3... 

B. Bubela. In situ biological production of surfactants for enhanced oil recovery. Australia Dep Resources Energy End of Grant Rep 151, March 1983. 

Single-Pass TFF Single-pass TFF or NFF operation is typical of water treatment. Low sofids allow high fluxes with high permeate product recovery and low retentate disposal costs. NFF operation is also used for virus retention in small-batch biologicals processing where low NFF fluxes (high areas) are compensated by ease of use, low residence time, and low capital costs. 

Dos Santos AB, Bisschops LAE, Cervantes FJ (2006) Closing process water cycles and product recovery in textile industry perspective for biological treatment. In Cervantes FJ, Van Haandel AC, Pavlostathis SG (eds) Advanced biological treatment processes for industrial wastewaters, vol 1. International Water Association, London, pp 298-320... 

Nicoud RM (1996) Recovery of Biological Products VIII, ACS, Tuscon, Arizona... 

Reft, M.E., Adams, K., and Anderson, D.R., Comparison of recombinant chimeric immunoglobulin secreted and purified from Chinese hamster ovary (CHO) and murine SP2/0 myeloma cells, in American Chemical Society Conference Recovery of Biological Products Vll, American Chemical Society, San Diego, CA, September 25-30, 1994, p. 26. 

Finally, it should be noted that this general technique may be used for a wide variety of separation processes in addition to immunoassays, where the isolation of a specific component in a biological fluid, industrial process stream or body of water is desired. Thus, product recovery and/or toxin or pollutant removal processes are possible with this methodology. 

The PHOSter II system is only applicable to contaminants that can be biologically degraded. In addition, it is only effective in settings where microbial activity is phosphorus limited. At sites with high contaminant concentrations, product recovery may be required during the initial treatment stage. Hydraulic conductivity and moisture content also determine the effectiveness of the PHOSter II technology. 

The complexity of biological processes generally requires many stages to produce a final, purified product from a particular composition of raw materials. Although a typical bioprocess consists of two main parts, upstream fermentation and downstream product recovery, it is not unusual to have between 10 and 20 steps in the overall process. This reflects the complex nature of a typical fermentation broth, which will consist of an aqueous mixture of cells, intracellular or extracellular products, unreacted substrates, and by-products of the fermentation process. From this mixture, the desired... 

The various steps in recovery of biological products from their natural environment have been divided into four categories.1 These are separation of solubles from insolubles, isolation, purification, and polishing. Separation of solubles from insolubles is a common chemical engineering operation and... 

Included here are short summaries of various oral presentations made at the Ninth Conference on Recovery of Biological Products, held on May 23-28, 1999, in Whistler, Canada. This conference has become the preeminent meeting in the field of bioseparations, and it provides exposure to the latest developments in the state-of-the-art downstream processing. Dr. S. Cramer of Rensselaer Polytechnic Institute was kind enough to cover this meeting, and his report follows. Various session titles are listed in the order of presentation. 

After biological reactions have generated a product of interest, it is necessary to recover this product from a liquid mixture that typically contains several undesirable components. The treatment of any culture broth after bioreactor cultivation is known as downstream processing. Downstream processing can account for 60-80%) of the total production cost, particularly in the production of modern recombinant proteins and monoclonal antibodies. A typical downstream process requires several steps in the areas of solid-liquid separation, cell rupture, product recovery, and product purification. It is important to minimize the number of downstream processing steps required because significant product losses inevitably occur during each step.f ... 

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