Parametric optimization of separation of succinic acid in groundnut oil with Tri‑n‑butyl phosphate using response surface methodology with central composite design

ABSTRACT

Succinic acid (SA) is a platform chemical for producing biofuel and other green chemicals. Fermentative SA production is a cost – effective and eco – friendly method, with quite a few downstream challenges. The recovery method of reactive extraction shows promise but faces toxicity issues with the diluent and extractant, especially concerning microorganisms in the fermentation broth. Hence, a non – toxic diluent and extractant, or less toxic combinations, are needed for efficient acid recovery. Hence, non – toxic diluents, groundnut oil and sesame oil, were evaluated. Based on the superior extraction efficiency (E%) achieved with groundnut oil, the study conducted reactive extraction of SA from the aqueous phase using tri-n-butyl phosphate (TBP) dissolved in groundnut oil. Using response surface methodology with central composite rotatable design, E% was maximized by optimizing independent variables, which were: initial SA concentration– 0.2525 mol L⁻¹, TBP concentration in groundnut oil as the extractant– 50%, shaking time–4 h, pH– 3. These conditions resulted in a distribution coefficient of 0.951 and E% of 48.75%, which are closely aligned with the predicted values of 0.953 and 50.21%, respectively. Fourier Transform Infrared Spectroscopy analysis confirmed a 1:1 complex formation in the organic phase. The results provide insights into the efficient recovery of SA from the fermentation broth.

Research Highlights

• Groundnut oil can be used as nontoxic diluent in succinic acid reactive extraction.

• CCD based RSM can be used to design the reactive extraction system.

• FTIR was used to analyze the interactions between the acid and extractant.

KEYWORDS:

• Succinic acid
• response surface methodology
• natural oil
• reactive extraction
• Fourier transform infrared spectroscopy

Acknowledgments

Science and Engineering Research Board (SERB), New Delhi, India for providing National Post–doctoral Fellowship (PDF/2021/004264) to Ms. Suvidha Gupta to carry out this research work. The authors would like to thank Norwegian University of Life Sciences (NMBU), Norway for its financial support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author’s contributions

SG: conception of idea and design of the experiments, experimentation and interpretation of data, writing the manuscript. FMA, AK: helped in the analysis of samples. JMM: Editing and proof – reading of the manuscript. KLW: conception of theory and experiments, supervision, editing and proof – reading of the manuscript.

Availability of data and material

The datasets analyzed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

This research work was supported by Science and Engineering Research Board (SERB), New Delhi, India [Grant No. PDF/2021/004264].