Fermentation fumaric acid

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. 

Problems Encountered During Fumaric Acid Fermentation. 265... 

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. 

Enzymatic amination of fumaric acid, fermentation route (under development)... 

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 ... 

ZhouY. Fumaric acid fermentation by Rhizopus oryzae in submerged systems. [Ph.D. thesis]. West Lafayette, Indiana, USA Purdue University 1999. 

Biological studies had indicated a role of folic acid and />-aminobenzoic acid in the transfer of single carbon units , and the isolation and proof of structure of a factor having folic acid activity for 5. faecalis R (S. lactis R) but not for L. casei gave chemical evidence for such a role - . This factor was named rhizopterin because it was isolated from Rhizopus nigricans fumaric acid fermentation liquors . The structure of rhizopterin was established as... 

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). 

Takao, S., Hotta, K., 1976. Conversion of fumaric acid fermentation to L-malic acid fermentation by the association of Rhizopus arrhizus and Proteus vulgaris. Journal of Fermentation Technology 54,197-204. 

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