Bio-based 3-hydroxypropionic- and acrylicacid production from biodiesel glycerol via integrated microbial and chemicalcatalysis

[摘要] Background3-Hydroxypropionic acid (3HP) and acrylic acid (AA) are industriallyimportant platform- and secondary chemical, respectively. Their production fromrenewable resources by environment-friendly processes is desirable. In thepresent study, both chemicals were almost quantitatively produced frombiodiesel-derived glycerol by an integrated process involving microbial andchemical catalysis.ResultsGlycerol was initially converted in a fed-batch mode of operation toequimolar quantities of 3HP and 1,3-propanediol (1,3PDO) under anaerobicconditions using resting cells of Lactobacillusreuteri as a biocatalyst. The feeding rate of glycerol wascontrolled at 62.5 mg/gCDW.h which is half the maximummetabolic flux of glycerol to 3HP and 1,3PDO through the L. reuteri propanediol-utilization (pdu) pathway to prevent accumulation of the inhibitoryintermediate, 3-hydroxypronionaldehyde (3HPA). Subsequently, the cell-freesupernatant containing the mixture of 3HP and 1,3PDO was subjected to selectiveoxidation under aerobic conditions using resting cells of Gluconobacter oxydans where 1,3PDO wasquantitatively converted to 3HP in a batch system. The optimum conditions forthe bioconversion were 10 g/L substrate and 5.2 g/L cell dry weight. Highersubstrate concentrations led to enzyme inhibition and incomplete conversion. Theresulting 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 integratedprocess for production of acrylic acid at high purity and -yield from glycerolthrough 3HP as intermediate without any purification step. The proposed processcould have potential for industrial production of 3HP and AA after furtheroptimization.Graphical abstractIntegrated three-step process forconversion of biodiesel glycerol to 3-hydroxypropionic acid(3HP) and acrylic acid (AA). Glycerol was initially converted toequimolar quantities of 3HP and 1,3-propanediol (1,3PDO) usingresting cells of Lactobacillusreuteri. Subsequently, the cell-free supernatantcontaining the mixture of 3HP and 1,3PDO was subjected toselective oxidation using resting cells of Gluconobacter oxydans where 1,3PDOwas quantitatively converted to 3HP. The resulting solution of3HP was dehydrated to AA over titanium dioxide (TiO2) at 230°C.

[发布日期] 2015-12-21

[关键词] Biocatalysis;Cascade enzymatic reaction;Lactobacillus reuteri;Gluconobacter oxydans;Catalytic dehydration;Titanium dioxide;3-Hydroxypropionic acid;Acrylic acid;1,3-Propanediol;Biodiesel glycerol