Fractionation of dicarboxylic acids produced by Rhizopus oryzae using reactive extraction

Lenuta Kloetzer,Anca-Irina Galaction,Alexandra Tucaliuc,Dan Caşcaval

doi:10.1038/s41598-022-06069-y

Lenuta Kloetzer, Anca-Irina Galaction + Show 2 more

Open Access

https://doi.org/10.1038/s41598-022-06069-y

Copy DOI

Abstract

Fumaric, malic, and succinic acids have been selectively separated from their mixture obtained by Rhizopus oryzae fermentation using reactive extraction with Amberlite LA-2 dissolved in three solvents with different dielectric constants (n-heptane, n-butyl acetate, and dichloromethane). This technique allows recovering preferentially fumaric acid from the mixture, the raffinate containing only malic and succinic acids. The extractant concentration and organic phase polarity control the efficiency and selectivity of acids extraction. The increase of aqueous phase viscosity reduces the extraction yield for all studied acids, but exhibits a positively effect on separation selectivity. By using Amberlite LA-2 concentration equal to that stoichiometrically required for interfacial reaction with fumaric acid and mixing intensity which does not allow higher diffusion rates for larger molecules (malic and succinic acids), the maximum value of fumaric acid extraction rate exceeds 90%, while the selectivity factor value becomes 20. Regardless of the extraction system, the complete separation of fumaric acid from their mixture is possible by multi-stage extraction process, adjusting the extractant concentration in each stage. At higher values of aqueous phase viscosity, more extraction stages are required, while the increase of solvent polarity reduce the required number of stages for total recovery of fumaric acid.

Highlights

Fumaric, malic, and succinic acids have been selectively separated from their mixture obtained by Rhizopus oryzae fermentation using reactive extraction with Amberlite LA-2 dissolved in three solvents with different dielectric constants (n-heptane, n-butyl acetate, and dichloromethane)
If the mechanism of the interfacial reaction is not changed by varying the dielectric constant value, the increase of the solvent polarity induces a positive effect on the extraction constant, due to the improvement of the solubilisation capacity of the interfacial complex by the organic phase[8,10]
The study on the reactive extraction with Amberlite LA-2 of fumaric, malic, and succinic acid from their mixture obtained by Rhizopus oryzae fermentation, using three solvents with different dielectric constants (n-heptane, n-butyl acetate and dichloromethane), indicated the possibility to remove selectively the fumaric acid from the mixture, malic and succinic acids remaining in the raffinate

Summary

Introduction

Malic, and succinic acids have been selectively separated from their mixture obtained by Rhizopus oryzae fermentation using reactive extraction with Amberlite LA-2 dissolved in three solvents with different dielectric constants (n-heptane, n-butyl acetate, and dichloromethane). This technique allows recovering preferentially fumaric acid from the mixture, the raffinate containing only malic and succinic acids. Rhizopus oryzae fermentation processes leads to the accumulation into the broth of a mixture of carboxylic acids, containing fumaric acid as the main product and small amounts of by-products, such as malic and succinic a cids[6,7]. Acids mixture includes: 85–90% fumaric acid, 7–9% malic acid, and 2–7% succinic a cid[6,7]

Methods

Results

Conclusion