1,3-Propanediol dehydrogenases in Lactobacillus reuteri: impact on central metabolism and 3-hydroxypropionaldehyde production

Microbial Cell Factories

Research

Marc JA Stevens¹  Leo Meile¹  Christophe Lacroix¹  Sabine Vollenweider² 

[1] Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich,, Schmelzbergstrasse 7, 8092, Zurich, Switzerland;Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich,, Schmelzbergstrasse 7, 8092, Zurich, Switzerland;Flavour Science & Technology, Natural Flavour Ingredients, Givaudan Schweiz AG, Ueberlandstrasse 138, CH-8600, Dübendorf, Switzerland;

关键词: Lactic Acid Bacterium;    Ethanol Production;    Early Stationary Phase;    Glycerol Conversion;    Lactobacillus Reuteri;   

DOI  :  10.1186/1475-2859-10-61

 received in 2011-01-31, accepted in 2011-08-03,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundLactobacillus reuteri metabolizes glycerol to 3-hydroxypropionaldehyde (3-HPA) and further to 1,3-propanediol (1,3-PDO), the latter step catalysed by a propanediol dehydrogenase (PDH). The last step in this pathway regenerates NAD+ and enables therefore the energetically more favourable production of acetate over ethanol during growth on glucose.ResultsA search throughout the genome of L. reuteri DSM 20016 revealed two putative PDHs encoded by ORFs lr_0030 and lr_1734. ORF lr_1734 is situated in the pdu operon encoding the glycerol conversion machinery and therefore likely involved in 1,3-PDO formation. ORF lr_0030 has not been associated with PDH-activity so far. To elucidate the role of these two PDHs, gene deletion mutant strains were constructed. Growth behaviour on glucose was comparable between the wild type and both mutant strains. However, on glucose + glycerol, the exponential growth rate of Δlr_0030 was lower compared to the wild type and the lr_1734 mutant. Furthermore, glycerol addition resulted in decreased ethanol production in the wild type and Δlr_1734, but not in Δlr_0030. PDH activity measurements using 3-HPA as a substrate revealed lower activity of Δlr_0030 extracts from exponential growing cells compared to wild type and Δlr_1734 extracts.During biotechnological 3-HPA production using non-growing cells, the ratio 3-HPA to 1,3-PDO was approximately 7 in the wild type and Δlr_0030, whereas this ratio was 12.5 in the mutant Δlr_1734.ConclusionThe enzyme encoded by lr_0030 plays a pivotal role in 3-HPA conversion in exponential growing L. reuteri cells. The enzyme encoded by lr_1734 is active during 3-HPA production by non-growing cells and this enzyme is a useful target to enhance 3-HPA production and minimize formation of the by-product 1,3-PDO.

【 授权许可】

Unknown   
© Stevens et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.