engleski

Fully integrated biotransformation of fumaric acid by permeabilized baker's yeast cells with in situ separation of L-malic acid using ultrafiltration, acidification and electrodialysis

L-malic acid is a dicarboxylic acid and an intermediate of cell metabolism. It belongs to a group of “bulk“ chemicals with estimated consumption of 40, 000 tons per year. It can be prepared by extraction from natural fruit juices or by bioconversion of fumaric acid with an enzyme fumarase. In this work a completely integrated production of L-malic acid from fumaric acid with in situ separation of L-malic acid was developed. Whole permeabilized cells of baker's yeast were used as biocatalyst. Baker's yeast was chosen in this biochemical reaction as an inexpensive and accessible source of the enzyme fumarase. The process of biotransformation of fumaric acid with in situ separation of product was composed of five process steps connected in series: biotransformation, crystallization with acidification, sedimentation, concentration using electrodialysis and dissolution by neutralization. The average conversion of fumaric acid has been increased from 77.5 % recorded in the continuous process to 91.3 % in the continuous process with in situ separation of product. At the same time, volumetric productivity of 15.1 g dm-3 day-1 achieved in the continuous process has been increased to 26.1 g dm-3 day-1 in the continuous process with in situ separation of product.

L-malic acid ; fumaric acid ; fumarase ; Saccharomyces cerevisiae ; in situ product separation

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