Diversity of Lactobacillus reuteri Strains in Converting Glycerol into 3-Hydroxypropionic Acid

J. Chem. Technol. Biotechnol.

Burgé

Chemarin

et al. 2015

BACKGROUND: Bioconversion is a promising route to produce bio-based building blocks such as 3-hydroxypropionic acid (3-HP). Reactive extraction can be used for 3-HP recovery, and ultimately integrated to the bioconversion process. To the best of our knowledge, there is no published experimental data about the reactive extraction of 3-HP. This work aimed to study the extraction of 3-HP using tri-n-octylamine and Aliquat 336 as extractants in n-decanol. Comparison was also made with its positional isomer, lactic acid. Finally, the extraction of 3-HP from model and real bioconversion broths was examined.

Section: Resultsmentioning

confidence: 91%

Reactive extraction of 3-hydroxypropionic acid from model aqueous solutions and real bioconversion media. Comparison with its isomer 2-hydroxypropionic (lactic) acid

J. Chem. Technol. Biotechnol.

Burgé

Chemarin

et al. 2015

“…Even if the production performance of these genetically modified microorganisms (GMM) has been significantly improved (yield around 0.5 g g −1 and final titer around 70 g L −1 ) compared with natural producers, 3‐HP biotechnological production at industrial scale is still difficult to consider. Observed limitations can be in part attributed to the fact that bacteria are subjected to product inhibition …”

Section: Introductionmentioning

confidence: 99%

“…Despite its promising and diverse applications, 3‐HP remains so far of limited use due to the low yield and high production cost of these chemicals routes . Nevertheless, several studies have demonstrated that a few microorganisms, including the Gram‐positive Lactobacillus reuteri , are naturally able to produce 3‐HP by glycerol bioconversion . Several works on the biotechnological production of this organic acid from glucose or glycerol using recombinant strains of Escherichia coli and Klebsiella pneumoniae and more recently by modified yeast strains of Saccharomyces cerevisiae have also been investigated .…”

Section: Introductionmentioning

confidence: 99%

Towards an extractive bioconversion of 3‐hydroxypropionic acid: study of inhibition phenomena

Burgé

J of Chemical Tech & Biotech

Saulou‐Bérion

et al. 2017

BACKGROUND: 3-hydroxypropionic acid (3-HP) microbial synthesis through glycerol bioconversion byLactobacillus reuteri is at the moment characterized by too low performances to consider production at industrial scale. To avoid its toxic accumulation in the medium and to recover this molecule of interest, 3-HP in situ reactive extraction from bioconversion broth was investigated using a hollow fiber membrane contactor (HFMC) in order to intensify its production. The so-called integrated system was compared with the conventional bioconversion system. The impact of the extractive bioconversion on the overall production performance and on cell physiological state was studied. RESULTS: Results underlined drastic inhibitory effects on the producing bacteria, especially under extractive bioconversion conditions despite the use of a HFMC supposed to avoid direct contact between organic phase and bacteria. Indeed, the extractant phase components (trioctylamine in n-decanol) were found to be toxic for the cells (due to solubility and by direct contact). These phenomena were increased by the presence of 3-hydroxypropionaldehyde (3-HPA) and 3-HP produced during glycerol bioconversion. These cumulative effects induced complete loss of the cell membrane integrity and esterase activity after 1.5 h of extractive bioconversion. When the bioconversion was conducted alone, the bacterial inhibition was lower, as around 50% of L. reuteri cells remained active with unaltered membrane after 3 h. Hypotheses concerning the mechanisms of action of the observed inhibitions were proposed and discussed.CONCLUSIONS: This work highlighted the importance of performing such an integrative approach to address specific questions prior to the optimization of the whole process.

“…Among the few microorganisms that can naturally produce 3‐HP, Lactobacillus reuteri is able to perform the bioconversion of glycerol, yielding only 3‐HP and 1,3‐propanediol (1,3‐PDO) . Although this pathway passes through 3‐hydroxypropionaldehyde (3‐HPA) production as an intermediate, which is toxic for the strain, its accumulation in the medium can be avoided by progressively supplying glycerol .…”

Section: Introductionmentioning

confidence: 99%

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

Sánchez-Castañeda

J of Chemical Tech & Biotech

Ngansop

et al. 2019

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