Production of high amounts of 3-hydroxypropionaldehyde from glycerol byLactobacillus reuteriwith strongly increased biocatalyst lifetime and productivity

Krauter, Hendrik; Willke, Thomas; Vorlop, Klaus-Dieter

Production of high amounts of 3-hydroxypropionaldehyde from glycerol byLactobacillus reuteriwith strongly increased biocatalyst lifetime and productivity

2012

Krauter, Hendrik | Willke, Thomas | Vorlop, Klaus-Dieter

3-Hydroxypropionaldehyde (3HPA) is a promising versatile substance derived from the renewable feedstock glycerol. It is a product of glycerol metabolism in Lactobacillus reuteri. Because of toxic effects, the biotechnological production is poor. In this work the biocatalyst lifetime and product formation could be drastically increased. In the established two-step process already applied, cells are grown in the first step under anaerobic conditions, and in the second step the immobilised or suspended biocatalyst is used for 3HPA-production under strict anaerobic conditions. In the first step it was possible to reach a biomass concentration of 5.5 g CDW/L (OD600 23.4). In the second step, normally, 3HPA accumulates to a toxic concentration and the reaction stops in less than 60 min because of the interaction of 3HPA with cell components. To prevent this, the toxic product is bound to the newly found scavenger carbohydrazide to form the hydrazone. For the first time it was possible to recycle the immobilised biocatalyst for at least ten cycles (overall life time >33 hours) in a repeated batch biotransformation with an overall production of 67 g 3HPA. The optimal pH-value was between 6.8 and 7.2 at an optimal temperature of 40458C. In a single batch biotransformation with suspended resting cells it was possible to produce 150 g/L 3HPA as carbohydrazone at an overall productivity of 10.7 g L -1 hours -1. In a single fed-batch biotransformation at 458C 138 g/L glycerol was converted into 108 g/L 3HPA with an overall productivity of 21.6 g L -1 hours -1. This is the highest 3HPA concentration and productivities reported so far for the microbial production of 3HPA from glycerol.

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