Bio-based 3-hydroxypropionic- and acrylic acid production from biodiesel glycerol via integrated microbial and chemical catalysis

Abstract

Background3-Hydroxypropionic acid (3HP) and acrylic acid (AA) are industrially important platform- and secondary chemical, respectively. Their production from renewable resources by environment-friendly processes is desirable. In the present study, both chemicals were almost quantitatively produced from biodiesel-derived glycerol by an integrated process involving microbial and chemical catalysis.ResultsGlycerol was initially converted in a fed-batch mode of operation to equimolar quantities of 3HP and 1,3-propanediol (1,3PDO) under anaerobic conditions using resting cells of Lactobacillus reuteri as a biocatalyst. The feeding rate of glycerol was controlled at 62.5 mg/gCDW.h which is half the maximum metabolic flux of glycerol to 3HP and 1,3PDO through the L. reuteri propanediol-utilization (pdu) pathway to prevent accumulation of the inhibitory intermediate, 3-hydroxypronionaldehyde (3HPA). Subsequently, the cell-free supernatant containing the mixture of 3HP and 1,3PDO was subjected to selective oxidation under aerobic conditions using resting cells of Gluconobacter oxydans where 1,3PDO was quantitatively converted to 3HP in a batch system. The optimum conditions for the bioconversion were 10 g/L substrate and 5.2 g/L cell dry weight. Higher substrate concentrations led to enzyme inhibition and incomplete conversion. The resulting solution of 3HP was dehydrated to AA over titanium dioxide (TiO2) at 230 °C with a yield of >95 %.ConclusionsThe present study represents the first report on an integrated process for production of acrylic acid at high purity and -yield from glycerol through 3HP as intermediate without any purification step. The proposed process could have potential for industrial production of 3HP and AA after further optimization.Graphical abstractIntegrated three-step process for conversion of biodiesel glycerol to 3-hydroxypropionic acid (3HP) and acrylic acid (AA). Glycerol was initially converted to equimolar quantities of 3HP and 1,3-propanediol (1,3PDO) using resting cells of Lactobacillus reuteri. Subsequently, the cell-free supernatant containing the mixture of 3HP and 1,3PDO was subjected to selective oxidation using resting cells of Gluconobacter oxydans where 1,3PDO was quantitatively converted to 3HP. The resulting solution of 3HP was dehydrated to AA over titanium dioxide (TiO2) at 230 °C.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-015-0388-0) contains supplementary material, which is available to authorized users.

Biological Production of 3-Hydroxypropionic Acid: An Update on the Current Status

“…Under optimal conditions, 3.3 g/L 3HP was produced during fed-batch feeding of the immobilized cells. Finally, a two-step process involving the cultivation of L. reuteri and G. oxydans has also been proposed [41]. More specifically, in the first step, the anaerobic cultivation of L. reuteri in fed-batch mode resulted in the production of equimolar quantities of 3HP and 1,3-propanediol, whereas in the second step, the 1,3-propanediol in the cell-free supernatant was selectively oxidized to 3HP by G. oxydans under aerobic batch cultivation.…”

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

“…3‐HP and 1,3‐PDO are the only products, at equimolar proportions . The feeding rate is adjusted to maintain a low glycerol concentration and avoid 3‐HPA accumulation, which is highly toxic for the strain . It was previously observed that glycerol and 3‐HPA did not have a significant effect on 3‐HP reactive extraction yield .…”

“…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 . This pathway has the advantage that no other by‐products are present, which simplifies further purification of the desired product.…”

Bio‐Acrylates Production: Recent Catalytic Advances and Perspectives of the Use of Lactic Acid and Their Derivates

“…The authors proposed γ‐alumina and silica catalysts with high surface area, whereas TiO 2 catalyst showed lower catalytic performance . In contrast, other patents reported an excellent performance of TiO 2 (anatase) with 99 % AA selectivity and full substrate conversion at 180–230 °C . Although no data on catalyst stability was mentioned in the original patents, Kamei et al.…”

“…[20] In contrast, other patents reported an excellent performance of TiO 2 (anatase) with 99 % AA selectivity and full substrate conversion at 180-230°C. [21][22][23] Although no data on catalyst stability was mentioned in the original patents, Kamei et al pointed to the presence of severe coking and thus poor stability performance of the alumina, titania and silica catalysts in function of time (on stream). [24] The deposition of alkaline and alkaline-earth metal salts was suggested to overcome this stability problem.…”