Fermentation product recovery costs

Process developers should check existing patents and patent applications in order to avoid patent infringement with any use or process patent. On the other hand, there may be possibilities to patent the particular process newly developed or critical elements of it. Economic aspects such as yields from cell culture or fermentation, product recovery after purification and cost of materials and equipment also need constant attention. Production cost forecasts should be calculated and updated regularly. 

High reaction rates could thus be maintained, and more concentrated feeds were allowed for fermentation [58,59]. The integration of part of the downstream processing in the bioreactor, allowing for ISPR-decreased product recovery costs [58], thus increased the competitiveness of the biochemical process. 

Some of the economic hurdles and process cost centers of this conventional carbohydrate fermentation process, schematically shown in Eigure 1, are in the complex separation steps which are needed to recover and purify the product from the cmde fermentation broths. Eurthermore, approximately a ton of gypsum, CaSO, by-product is produced and needs to be disposed of for every ton of lactic acid produced by the conventional fermentation and recovery process (30). These factors have made large-scale production by this conventional route economically and ecologically unattractive. 

The ultimate goal of process development is to achieve feasibility where it is possible to produce amino adds on a large scale at a production cost per kg of amino add comparable to, or cheaper than, the processes currently used by other companies. If we presume that the technical performance (fermentation and recovery) are sorted out on a laboratory scale and scaling up looks promising, then it is time to find out whether it is possible to operate economically on a large scale. 

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... 

Fine and specialty chemicals can be obtained from renewable resonrces via multi-step catalytic conversion from platform molecules obtained by fermentation. An alternative method decreasing the processing cost is to carry out one-pot catalytic conversion to final product without intermediate product recovery. This latter option is illustrated by an iimovative oxidation method developed in our laboratory to oxidize native polysaccharides to obtain valuable hydrophilic end-products useful for various technical applications. 

The fermentation step to produce penicillin GA is the major cost element in the overall process to produce 6-APA. This is substantially due to the high cost of sterile engineering (Table 4.6 and 4.7). Clarification, extraction and solvent recovery steps are also significant, a reflection of the dilute and impure composition of fermentation broths. The concentration of 6-APA in the final broth has a big effect on total process costs. Thus increasing final 6-APA concentrations from 1.2-6.0% have been calculated to reduce production costs by over 50% (Table 4.8). By contrast the 6-APA production step cost is quite small, and is less that half the cost of the solvent recovery process (Table 4.6). The costs of the immobilized enzyme is not insignificant in a recent calculation it was estimated at 2.5 /kg 6-APA (Rasor and Tischer, 1998). 

The isolation and purification of fermentation products is often collectively referred to as downstream processing. The early part of the separation of a bioproduct is the primary recovery process, whereas the elements further downstream may include purification, concentration, and formulation. The overall goal of downstream processing and formulation is to recover the product of interest cost effectively at high yield, purity, and concentration, and in a form that is stable, safe, and easy to use in a target application. 

Another important problem in the production of chemicals by fermentation is that the products are obtained in diluted form in an aqueous soup that contains many components. Concentrating the solutions and separating the products from the other products of the fermentation broth is tedious and often the main cost factor. About 60 to 95 percent of the total cost is for product recovery. 

Monosodium glutamate (MSG) is a flavor enhancer. U.S. 2,877,160 (to Pfizer) and U.S. 2,978,384 (to Koichi Yamada) describe fermentation processes for glutamic acid. U.S. 5,907,059 (to Amylum Belgium A. E. Staley Manufacturing) describes recovery of the fermentation product and conversion to MSG. Estimate the cost of production via this route. 

Cyclosporins are a group of cyclic nonpolar oligopeptides that are immunosuppressants and are produced by Tolypodadium inflatum Gams and other fungi. U.S. 4,117,118 gives details of the fermentation and product recovery. Estimate the cost of production and determine which species is preferred. 

The process of recovering and purifying fermentation products in the biochemical industries is generally difficult and costly. The product can exist intracellularly or extracellularly and it may be sensitive to temperature change, extremes of pH, certain chemicals and enzyme activities of the microorganisms. Frequently, the energy and labor costs spent on recovery and purification of the fermentation product far exceed the cost of fermentation. This is especially true for intracellular recombinant protein products ... 

Although the partition coefficients of ABE fermentation products was smaller in MFA (1.4 to 4-fold smaller) as compared to oleyl alcohol [92], cheap sources of esters, such as palm oil, were found. Furthermore, effluents from the palm oil industry provided adequate substrates for ABE fermentations [93], and since MFA could be employed as biodiesels, coupling ABE production with MFA to yield biodiesels, thus avoiding the costly solvent recovery step, was suggested [92]. 

Capital costs include the cost for the reaction equipment such as reactors or fermenters, as well as for separation devices such as membrane systems and all the other apparatuses for product recovery and feed pretreatment. 

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