Organic phase screening for in‐stream reactive extraction of bio‐based 3‐hydroxypropionic acid: biocompatibility and extraction performances

Abstract

BACKGROUND 3‐Hydroxypropionic acid (3‐HP) production through glycerol bioconversion by Lactobacillus reuteri suffers from low yields and productivities due to product inhibition. Reactive extraction assisted by a Hollow Fibre Membrane Contactor (HFMC) is a promising strategy for process intensification. However, the use of this integrated system is hindered by extraction phase toxicity towards the microorganism. This study describes a solvent selection strategy based on extraction performance (extraction yield and viscosity, related to mass transfer), and a low solvent toxicity, in order to find an extraction phase composition that allows continuous in stream extraction of 3‐HP. RESULTS Inert diluent addition to a trioctylamine (TOA)‐decanol mixture decreased its toxicity and viscosity but decreased extraction yield. The linear and ramified long‐chain alcohols tested showed that increasing the number of carbon atoms decreased extraction performance as well as toxicity. Ramified alcohols showed the lowest extraction performance. Didodecylmethylamine (DDMA) gave higher extraction yield and lower solvent toxicity than TOA. Flow cytometry with dual staining for cell membrane integrity and enzymatic activity proved to give concordant and complementary information with cell bioconversion ability, being an adequate and quick method for solvent toxicity assessment. The selected organic phase consisted of 20% DDMA, 47% dodecanol and 33% dodecane by volume, and can be used for in‐stream extraction of 3‐HP produced by L. reuteri. CONCLUSIONS The integrated selection criteria proposed in this study – extraction yield, solvent viscosity and toxicity – provide key information for choosing an organic phase with the best trade‐off between extraction performance and biocompatibility. © 2019 Society of Chemical Industry

Solvent Selection for the Extraction of 2-Phenylethanol from Aqueous Phases: Density and Viscosity Studies

“…Figure A presents that mixtures of 2-phenylethanol with methyl isobutyl ketone and 2-methyl-3-buten-2-ol have the more negative excess volumes, and Figure B shows that these solvents have lower viscosities than 2-phenylethanol. These characteristics indicate that these solvents could be good extracting agents for ISPR of 2-phenylethanol from fermentation broth in terms of their volumetric and transport properties. , Moreover, methyl isobutyl ketone and 2-methyl-3-buten-2-ol are categorized as ”recommended” based on CHEM21 methodology (Table ) because they have flash points higher than 333.15 K, boiling points between 343.15 K and 412.15 K, and according to GHS, do not have any significant risk . Also, methyl isobutyl ketone is relatively inexpensive and is cataloged as recommended for green processes based on the list published by Esteban et al The biggest challenge for the incorporation of the solvents in an ISPR is related to the biocompatibility or low-toxicity on the yeast, , so further studies are required for understanding the yeast–solvent behavior.…”

“…Also, methyl isobutyl ketone is relatively inexpensive and is cataloged as recommended for green processes based on the list published by Esteban et al The biggest challenge for the incorporation of the solvents in an ISPR is related to the biocompatibility or low-toxicity on the yeast, , so further studies are required for understanding the yeast–solvent behavior. Nevertheless, these problems might be overcome by using coupled liquid–liquid extraction with membrane systems to avoid direct contact between the microorganisms and solvents in the case of the lack of biocompatibility. ,− …”

“…However, an adequate and meticulous solvent selection is required. Thus, the extracting solvent must be poorly soluble in water, nonflammable, inexpensive, selective, and biocompatible. ,− …”

Reactive liquid–liquid extraction of bio-based 3-hydroxypropionic acid using a biocompatible organic phase containing a tertiary amine: A model-based approach to elucidate dominant mechanisms

“…The main drawback of reactive liquid-liquid extraction as ISPR technique remains the toxicity of the extraction phases in close contact with culture media. Recently, several studies have been published on the screening and formulation of organic phases accounting for the biocompatibility with some bacteria of the genus Lactobacillus [15,16]. In spite of the identification of more biocompatible organic phases, most experimental and equilibrium modeling studies so far focused on trioctylamine (TOA)…”

“…The objective of this work is thus to propose an equilibrium model of the extraction of 3-hydroxypropionic acid using a new formulation of organic phase that has been identified from literature to be more biocompatible than other organic phases employed for 3-HP extraction [15,17]. Among promising biocompatible organic phases, we chose to focus on N,N-didodecylmethylamine (DDMA) diluted in a mixture of 1-dodecanol and dodecane as active and inactive diluent, respectively, according to the recent study of Sánchez-Castañeda et al [15]. The authors found that DDMA showed better performances than TOA in terms of distribution coefficient as well as biocompatibility towards the natural 3-HP producer microorganism Lactobacillus reuteri.…”