In their review article entitled “Modelling strategies for the industrial exploitation of lactic acid bacteria”, Teusink and Smid describe industrial applications of lactic acid bacteria (LAB) and the use of metabolic modelling to enhance production processes1. The focus of the review is on the exploitation of metabolic control to obtain increased bacterial biomass and improved production of biomolecules for health and food applications.
In respect to the above, we find it remarkable that the authors failed to mention respiratory metabolism, a central metabolic capacity common to several of the LAB discussed in this article. The most studied industrial LAB, Lactococcus lactis, is capable of respiratory metabolism when supplied with exogenous heme. This has been unequivocally demonstrated and characterized experimentally, and has gained considerable attention over the past six years through publications, patents and reports at major scientific congresses2,3,4,5,6,7,8,9,10,11,12.
Respiratory metabolism has several consequences for biomass and metabolite production, stability and storage2,3,6,13, which are the key industrial objectives addressed by Teusink and Smid. First, the biomass of L. lactis is essentially doubled as a consequence of respiratory metabolism, when compared to fermentation metabolism (Table 1). Second, under respiratory growth conditions in liquid, the bacterial cultures are significantly more stable when compared to cultures grown under conventional (static or aerobic) fermentation conditions (Table 1). These published results have an obvious impact on industrial processes where increased biomass and long-term survival characteristics are important, and are clearly relevent to modelling strategies. To date, respiratory growth is among the few metabolic 'manipulations' of LAB that have been scaled up to an industrial level, and starter cultures for cheese making have been produced under respiratory growth conditions since 2002 (Ref. 5.). The published data referred to in this letter should give readers a more complete picture of the metabolic potential of LAB.
References
Teusink, B. & Smid, E. J. Modelling strategies for the industrial exploitation of lactic acid bacteria. Nature Rev. Microbiol. 4, 46–56 (2006).
Duwat, P. et al. Respiration capacity of the fermenting bacterium Lactococcus lactis and its positive effects on growth and survival. J. Bacteriol. 183, 4509–4516 (2001).
Gaudu, P. et al. Respiration capacity and consequences in Lactococcus lactis. Antonie van Leeuwenhoek 82, 263–269 (2002).
Gaudu, P., Lamberet, G., Poncet, S. & Gruss, A. CcpA regulation of aerobic and respiration growth inLactococcus lactis. Mol. Microbiol. 50, 183–192 (2003).
Pedersen, M. B., Iversen, S. L., Sorensen, K. I. & Johansen, E. The long and winding road from the research laboratory to industrial applications of lactic acid bacteria. FEMS Microbiol. Rev. 29, 611–624 (2005).
Rezaiki, L. et al. Respiration metabolism reduces oxidative and acid stress to improve long-term survival of Lactococcus lactis. Mol. Microbiol. 53, 1331–1342 (2004).
Vido, K. et al. Proteome analyses of heme-dependent respiration in Lactococcus lactis: involvement of the proteolytic system. J. Bacteriol. 186, 1648–1657 (2004).
Sijpesteijn, A. K. Induction of cytochrome formation and stimulation of oxidative dissimilation by hemin in Streptococcus lactis and Leuconostoc mesenteroide. Antonie van Leeuwenhoek 36, 335–348 (1970).
Blank, L. M., Koebmann, B. J., Michelsen, O., Nielsen, L. K. & Jensen, P. R. Hemin reconstitutes proton extrusion in an H+-ATPase-negative mutant of Lactococcus lactis. J. Bacteriol. 183, 6707–6709 (2001).
Duwat, P., Sourice, S. & Gruss, A. Process for preparing starter cultures of lactic acid bacteria. Patent application WO0005342 (1998).
Duwat, P., Gruss, A., Le Loir, Y. & Gaudu, P. Lactic acid bacteria transformed to be provided with respiratory metabolism. Patent application WO0121808 (1999).
Geppel, A., Kringelum, B., Hansen, K. F., Iversen, S. L. & Henriksen, C. M. Porphyrin containing lactic acid bacterial cells and use thereof. Patent application WO01/52668 (2000).
Kaneko, T., Takahashi, M. & Suzuki, H. Acetoin fermentation by citrate-positive Lactococcus lactis subsp. lactis 3022 grown aerobically in the presence of hemin or Cu. Appl. Environ Microbiol. 56, 2644–2649 (1990).
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Garrigues, C., Johansen, E., Pedersen, M. et al. Getting high (OD) on heme. Nat Rev Microbiol 4, 318 (2006). https://doi.org/10.1038/nrmicro1403-c1
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DOI: https://doi.org/10.1038/nrmicro1403-c1
