Fumaric acid fermentative production

In the present study, we evaluated a two-step process for succinic acid production. The first process was fumaric acid production by Rhizopus sp. using rice bran, and the second process was succinic acid production by Enterococcus faecalis RKY1 (5-7) using fungal culture broth obtained in the first process. We investigated the effects of rice bran on fumaric acid production and optimized the culture medium for fumaric acid fermentation. Furthermore, we optimized the culture conditions for succinic acid conversion from fumaric acid produced by the first process. 

The principal operating costs associated with fermentation processes of low value compounds are the costs of the fermentation substrate, which for fumaric acid amounts to about 50-55% of total production costs. The small differential that normally exists between substrate and the product prices is one of the major intrinsic limitations of commercial fumaric acid fermentation. The break-even price for production is dependent on the price that can be obtained for the product, compared to the price paid for the substrate. The current prices commanded by purpose-grown crops in most developed countries make it difficult for the fermentation route to compete economically. The use of lower value agricultural, industrial, and domestic wastes could help improve the economics but the variable nature of these types of materials makes them much less attractive as fermentation substrates. For the idealized case described by Gangl et al. (1990), substrate cost was 75% of the total cost, mainly due to reduction in equipment cost and also taking into account the higher productivity for formation of fumaric acid. 

Aspects determining the productivity of fumaric acid fermentation include the microbial strain used and its morphology, the use of a neutralizing agent, and the applied feedstock. 

Continuous pH neutralization is necessary for optimal yields in fumaric acid fermentation. At low pH, excreted fumaric acid will passively diffuse back through the plasma membrane of the fungus and decrease its intracellular pH as a result, the fermentation will fail. In addition, free fumaric acid accumulated in the medium decreases the pH, which exerts a progressive inhibitory effect on fumaric acid production. O ... 

Usually submerged batch fermentation is used for fumaric acid fermentation. Table 11.2 includes important results achieved with Rhizopus strains, and as is shown there R. arrhizus NRRL 1526 gave the highest volumetric productivity, product titer and product yield values (Ling and Ng 1989). 

Foster and Waksman (1938) supplied ethanol as the only carbon source and found that 70% was converted to fumaric acid. Using glucose, transient accumulation of ethanol is often observed, and apparently this might later be converted into fumaric acid. Glycerol, another potential side-product of fumaric acid fermentation, can also serve as carbon source for formation of fumaric acid (Moon et al. 2004). 

A novel immobilization device using net and wire for filamentous R. arrhizus RH-07-13 for fumaric acid fermentation was developed. Abundant mycelia grew on a large surface of the net and consumed glucose rapidly with a transit of nutrients across the net, resulting in rapid fumaric acid production. The result was around 32.03 g/L of fumaric acid production, in comparison to free-cell fermenfafion (31.23g/L), and a further reduction in fermentation time from 144 fo 24h (Gu et al., 2013). 

Fumaric acid is used in the plastics industry, in the food industry and as a source of malic add. Although demand has increased rapidly over the last 30 years its production from fermentation has been totally replaced by a chemical method. It is now produced far more cheaply by the catalytic oxidation of hydrocarbons, particularly benzene. With the continuing uncertainties concerning the availability and cost of petroleum, however, fermentation may yet be a viable alternative. 

Fumaric acid, a metabolite of many fungi, lichens moss and some plants, and mainly used as the diacid component in alkyd resins, is produced commercially to some extent by fermentation of glucose in Rhizopus arrhizus yet productivity improvements appear essential for the product to be an option for replacing its petrochemical production by catalytic isomerization of maleic acid. 

Carta, E. S. Soccol, C. R. Ramos, L. P. Fontana, J. D. Production of fumaric acid by fermentation of enzymic hydrolyzates derived from cassava bagasse, Bioresour. Technol, 1999, 68, 23-28. 

To optimize the culture medium for fumaric acid production, we investigated the effects of rice bran concentrations and various carbon sources. When rice bran was used as a nitrogen source, the effects of additional elements (phosphate, magnesium, zinc, and iron) on fumaric acid production were also investigated. The medium previously reported by Zhou et al. (11) was used as the basal medium. Fermentations were performed in 250-mL Erlenmeyer flasks containing 100 mL of medium. 

Batch fermentations were carried out using rice bran and glucose as nitrogen and carbon sources, respectively. Figure 4 shows the profile of fumaric acid production in a 2.5-L jar fermentor. The fumaric acid concentration reached 25.3 g/L. The yield (fumaric acid produced/glucose consumed) and the productivity were 52% and 0.21 g/(L-h), respectively. For the following experiment, the fungal culture broth was used as a medium for the bioconversion of fumaric acid into succinic acid. 

Malic acid (hydroxybutanedioic acid) is a chemical intermediate and is also used as a food flavor enhancer. It can be made by several routes. U.S. 5,210,295 (to Monsanto) describes a nonenzymatic process. U.S. 4,772,749 (to Degussa) describes recovery of malic acid from the product of enzymatic conversion of fumaric acid. U.S. 4,912,042 (to Eastman Kodak) describes an enzymatic separation process for separating the L- and D-isomers. U.S. 5,824,449 (to Ajinomoto Co.) describes a selective fermentation from maleic acid. Estimate the cost of production of D-malic acid by each process and determine which is cheapest. 

Under anaerobic conditions, in the absence of alternative and much more energetically favorable electron acceptors, such as nitrate or fumarate, Ecoli utilizes the mixed acid fermentation pathway. Since the fermentation products are not only carbon dioxide and... 

Besides the production of L-lactic acid, the fermentation process can simultaneously produce various other metabolites such as acetic acid, f umaric acid, ethanol, malic acid, etc. However, the amount of these metabolites can have a significant influence on the downstream process and the quality of the L(+)-lactic acid produced (Wang et al., 2005). Fumaric acid is the main by-product and its accumulation is affected by many factors,... 

Although the production of fumaric acid from either glucose, sucrose, starch, or molasses by fermentation using Rhizopus was in commercial operation during the 1940s, it was discontinued due to low productivity and the cheap source of petroleum-derived feedstock. 

Fumaric acid can also be produced from xylose. The rate of xylose fermentation is much slower than with glucose with a specific productivity of only about 0.075 g fumaric acid/h/g biomass. Kautola and Linko [73] used immobilized R. arrhizus with polyurethane foam to ferment xylose. A specific productivity of 0.087 g/l/h was obtained when the initial xylose concentration was 100 g/1 and the resident time was 10.25 days. 

Fumaric acid production from starch hydrolysate by R. arrhizus NRRL 1526 was studied by Federici et al. [75] in a 3-1 stirred-tank fermentor with CaCO, and KOH/KCO3 as the neutralizing agent and CO2 source. The fermentation conditions for fumaric acid production by this fungus from potato flour has been optimized by Moresi et al. [76]. 

The first commercial production of L-aspartic acid was started in 1973 by the Tanaba Seiyaku Company, Japan. The process uses aspartase contained in whole microorganisms and involves the immobilization of E. coli on polyacrylamide gel or carrageenan. The immobilized cells are then subjected to treatment in order to increase cell permeability. The substrate, fumaric acid, is dissolved in a 25 % ammonia solution and the resulting ammonium fumarate is then passed through the reactor containing the immobilized E. coli. The reaction is exothermic and the reactor has to be designed to remove the heat produced. The conversion of fumaric acid to aspartic acid is more economical than the direct fermentation of sugars. The key to economical production of L-aspartic acid for expanded use is a cheaper and more abundant source of fumaric acid. 

The fermentation is carried out according to the procedure in Example 1. After 7-9 days incubation, the production of alkaloids reaches the value of 1000 ug./mL. The same yield is obtained if tartaric acid, citric acid, malic acid, acetic acid, fumaric acid, succinic acid are used. 

Brief attention has been directed in Chapter 4, Section 4.3.4 to anaerobic bacteria that are important in the decarboxylation of dicarboxylic acids including oxalate and malonate—and succinate that is produced as a fermentation product of carbohydrates, and in anaerobic respirations involving fumarate. The various anaerobic organisms, and their metabolic capabilities are briefly summarized here ... 

---