Author ORCID Identifier
https://orcid.org/0000-0003-2455-3024
Date of Award
17-8-2025
Document Type
Thesis
School
School of Chemical & Biotechnology
Programme
Ph.D.-Doctoral of Philosophy
First Advisor
Dr.R.Senthilkumar
Keywords
Extractive Fermentation, Deep Eutectic Solvents, Enzymes, Reactor design, Purification
Abstract
The increasing demand for sustainable and efficient bioprocessing techniques has prompted the development of novel separation strategies integrating bioproduction with downstream processing. Extractive fermentation has emerged as a promising process intensification to overcome product inhibition and enhance productivity by constantly removing target biomolecules from the fermentation medium. Although the extractive fermentation of acids and alcohols has been extensively studied, less attention has been focused on green solvents and their compatibility, phase-forming abilities, and reactor configurations.
Therefore, advancing extractive fermentation technology necessitates comprehensive studies on solvent systems and the development of modified bioreactor configurations to aid future optimization. Initially, 22 DESs were prepared under four sub-classes (SDES, GDES, PNDES, and PDES), and their physical properties were characterized as a function of temperature, followed by the screening of DESs for the extractive fermentation process based on their partition coefficient and phase ratio.
Among the four groups, GDES was observed to perform better, exhibiting a density (1.005 to 1.071 g/cm3), viscosity (0.004 to 0.483 kg/m/s), and excess molar volume (-20.108 to - 46.926 cm3/mol). Additionally, GDES achieved a partition coefficient of 3.6 and a phase ratio of 3.9. The process feasibility was demonstrated using fibrinolytic protease (FLP) as a model bioproduct, facilitated by customizing reactor configurations to support extractive fermentation.
Hydrodynamic parameters were evaluated as they directly influence mass transfer, phase separation, and overall process efficiency with an enhanced hold-up volume of 67 %, a residence time of 11.3 min, and a mass transfer coefficient rate of 9.78 min-1. The interfacial area (804 m2/m3) revealed the total surface area available for the mass transfer between the aqueous and solvent phases for the efficient transfer of biomolecules. ΔG°E (-8.95 KJ/mol), ΔH (6.389 KJ/mol), and ΔS (0.0490 KJ/mol K) data were evident that the product partitioning was thermodynamically favorable and spontaneous, ensuring the phase behavior and solvent stability.
The activation energy (48.3 kJ/mol), deactivation constant (0.055 min-1), and half-life time (12.6 min) determine the enzyme transition and stability in the DES environment. In addition, a life cycle analysis was conducted for sustainability improvement and to quantify the environmental impacts of the integrated process. The obtained outcomes underscore the potential of extractive fermentation to revolutionize industrial and pharmaceutical production by enhancing yield and reducing costs. Thus, eco-friendly bioprocessing with green solvents has a significant breakthrough in sustainable bioprocessing.
Recommended Citation
M, Ramya Ms, "Design and Investigation of Deep Eutectic Solvent-Assisted Extractive Fermentation of Biomolecules" (2025). Theses and Dissertations. 134.
https://knowledgeconnect.sastra.edu/theses/134