Eco-efficient recovery of bio-based volatile C2–6 fatty acids

Abstract

Background Volatile fatty acids (VFAs) are produced by fermentation of various bio-sources and human wastes at minimal cost; sometimes, even sources having a prepaid processing fee were used. However, low concentrations of VFAs in water have prevented their commercial production, even with modern separation technologies, due to the high operating costs. We have applied newly developed solvents, selected by chemical structure similarity, to the separation of five different VFAs. Results Since most of the water was separated by extraction using hexyl acetate and nonyl acetate, the utilities necessary for solvent recovery and product purification were a fraction of those required by the existing VFAs’ separation processes. The solvents separated almost all the water in the feed at the extraction stage, consuming no energy. The energy use in this study is only 34% of the lowest case use among various processes of either distillation-only or combined extraction–distillation. Conclusions The performance evaluation of the proposed VFAs separation process showed that product recovery was 99% and acid purity was 99.5% with eco-scores of 70% lower than those of the current processes. Electronic supplementary material The online version of this article (10.1186/s13068-019-1433-8) contains supplementary material, which is available to authorized users.

Valorization of volatile fatty acids from the dark fermentation waste Streams-A promising pathway for a biorefinery concept

“…At the end of the acidogenic process, the effluents, which mainly consist of volatile fatty acids, alcohols, and other residues, are used as precursors for secondary bioprocesses [2,16]. Volatile fatty acids (VFAs) are reported as being the most critical precursors in biorefinery owing to their functional groups which allows them to be used in various industrial applications including chemicals [17], bioplastics [18], biofuels [16], and wastewater treatment [19]. The demand for VFAs is expected to increase rapidly over the next years due to their numerous applications [19].…”

Integrating torrefaction of pulp industry sludge with anaerobic digestion to produce bioenergy and biochemicals: Techno-economic and environmental feasibility analysis

“…The high pressure water scrubbing was considered for biogas purification. In case of VFA recovery, the multi-step solvent extraction presented by [14] was considered. As the condensate is highly inhibitory to the AD, diluting it with water at a rate of 50% was considered.…”

Valorisation of CO2 into Value-Added Products via Microbial Electrosynthesis (MES) and Electro-Fermentation Technology

“…The process of protraction is generally employed for extracting VFAs. It is the favoured process over liquid-liquid extraction as it is a simultaneous process, solvent stripping occurs, it is not expensive and the amount of solvent required is also little [209].…”