title: Influence of environmental parameters on production of the acrolein precursor 3-hydroxypropionaldehyde by Lactobacillus reuteri DSMZ 20016 and its accumulation by wine lactobacilli.
abstract: Lactic acid bacteria belonging to the genus Lactobacillus are known to convert glycerol into 3-hydroxypropionaldehyde (3-HPA) during anaerobic glycerol fermentation. Wine quality can be gravely compromised by the accumulation of 3-HPA, due to its spontaneous conversion to acrolein under wine making conditions. Acrolein is not only a dangerous substance for the living cell, but has been implicated in the development of unpleasant bitterness in beverages. This study evaluates the effect of individual environmental parameters on 3-HPA production by Lactobacillus reuteri DSMZ 20016, which only proved possible under conditions that allow accumulation well below the threshold concentration affecting cell viability. 3-HPA production was optimal at pH 6 and in the presence of 300 mM glycerol. Production increased with an increase in cell concentration up to an OD(600) of 50, whereas higher cell concentrations inhibited accumulation. Data presented in this study suggest that 3-HPA plays a role in regulating its own production through quorum sensing. Glycerol dehydratase possessing bacterial strains isolated from South African red wine, L. pentosus and L. brevis, tested positive for 3-HPA accumulation. 3-HPA is normally intracellularly reduced to 1,3-propanediol. This is the first study demonstrating the ability of wine lactobacilli to accumulate 3-HPA in the fermentation media. Recommendations are made on preventing the formation of acrolein and its precursor 3-HPA in wine.
authors.affiliation: Institute for Plant Biotechnology, Genetics Department, Stellenbosch University, Matieland 7602, Stellenbosch, South Africa. rbauer@uwc.ac.za
authors.forename: Rolene
authors.initials: R
authors.lastname: Bauer
authors.forename: Maret
authors.initials: M
authors.lastname: du Toit
authors.forename: Jens
authors.initials: J
authors.lastname: Kossmann
mesh_terms: D000171:Acrolein / Q000378:metabolism* / Q000633:toxicity; D000693:Anaerobiosis; D018533:Biomass; D001711:Biotransformation; D005285:Fermentation; D005506:Food Contamination / Q000517:prevention & control; D005516:Food Microbiology; D005985:Glyceraldehyde / Q000031:analogs & derivatives* / Q000378:metabolism / Q000633:toxicity; D005990:Glycerol / Q000378:metabolism; D052200:Limosilactobacillus reuteri / Q000378:metabolism*; D026901:Membrane Transport Proteins; D011407:Propane / Q000378:metabolism* / Q000633:toxicity; D053038:Quorum Sensing; D013019:South Africa; D014920:Wine / Q000032:analysis* / Q000382:microbiology* / Q000633:toxicity
chemical_list: D026901:Membrane Transport Proteins; C047158:3-hydroxypropionaldehyde; D005985:Glyceraldehyde; D000171:Acrolein; D005990:Glycerol; D011407:Propane