Synergistic and antagonistic effects of microorganisms

Interactions that occur between differents microorganisms

1. Synergistic and antagonistic effects of microorganisms M. ANZA Adamou

2. Introduction The world seen as a system, works following the different interactions between living beings. Far from the macro aspect of the system, microorganisms also interact with each other according to their genetic characteristics in order to ensure their survival as well as their development. Most food fermentation processes involve mixed cultures in which different microbial species interact with each other. These interactions may have neutral, positive or negative effects on the fitness of the strains performing the fermentation.( Arioli , Della Scala et al. 2016)

3. Synergistic effect Synergy is a type of phenomenon whereby several factors acting together create an overall effect distinct from anything that could have happened if they had operated in isolation, either individually or together, but working independently. There is therefore the idea of creative cooperation.( Wikipédia ) The synergistic effect of the microorganisms would therefore be the result obtained by the use of two or more microorganisms functioning in a synergistic manner in order to obtain a better result.

4. Synergistic effect Mixed-strain culture fermentation is an effective approach to obtain the desired product characteristics and to reduce fermentation time in most food fermentation processes ( Laiño et al., 2014; Smid and Lacroix , 2013). For example, yogurt is typically produced using mixed starter cultures comprised of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus .

5. Synergistic effect The molecular interactions that play key roles in the mutualistic behaviour of the yogurt consortium have been investigated using several approaches and have been reviewed by several authors ( Sieuwerts et al., 2008; Smid and Lacroix , 2013). Validated interactions between S. thermophilus and L. delbrueckii during the growth of these species in milk have been described in relation to: The availability of nitrogen in milk, The exchange of formic acid, pyruvic acid and folic acid, The production and utilisation of carbon dioxide, And the metabolism of purine , amino acid, long-chain fatty acids and iron.

6. Synergistic effect A schematic summary of these metabolic interactions is presented in Fig. 1. As expected, most of the previously described interactions are trophic interactions in which the species feed each other with pyruvate , folate , long chain fatty acids, ornithine , carbon dioxide, peptides, amino acids and putrescine ).

7. Fig. 1. Graphic representation of the molecular interactions that play key roles in the mutualistic behaviour of the yogurt consortium. The effect of S. thermophilus urease on urea hydrolysis and the hypothetical role of the NH3 released by this enzyme on the ... Stefania Arioli , Giulia Della Scala , Maria Chiara Remagni , Milda Stuknyte , Stefano Colombo, Simone Guglielmetti , Ivano De Noni , Enzio Ragg , Diego Mora Streptococcus thermophilus urease activity boosts Lactobacillus delbrueckii subsp. bulgaricus homolactic fermentation International Journal of Food Microbiology, 2016, Available online 20 January 2016 http://dx.doi.org/10.1016/j.ijfoodmicro.2016.01.006

8. Antagonistic effects Antagonism is hostility that results in active resistance, opposition, or contentiousness. It is in this logic that some microorganisms often alter the pH of the environment (by turning acid), osmotic pressure and surface tension, with metabolic debris that they secrete. In this case they prevent the activation or even destroy the enzymes of other microorganisms. Some toxic substances or antimicrobial products (bacteriocins, antibiotics) also directly control the replenishment of the other. For example, Lactabacillus strains quickly produce lactic acid in yoghurt, which prevents other bacteria from reproducing or even surviving ( Canan Öztoprak , 2016).

9. Antagonistic effects The antibiotic is used by VVaksmann to explain the effect of antagonist movement and to produce microorganisms and to inhibit (microbiostatic, bacteriostatic) and / or lethal (microbiolytic, bacteriolytic) action on other microorganisms. The penicillins obtained from Penicillium notatum are the first antibiotic (Aleksandr Fleming). Gramicin synthesized by Bacillus brevis, Streptomyces fungi synthesized by streptomycin, chloramphenicol, tetracyclines, kanamycin.

10. Antagonistic effects Y. lipolytica contributes to create body and/or texture of the cheese and its organoleptic characteristics like taste and aroma. Cheese aroma is generated due to the production of volatile sulfur compounds, including methanethiol, dimethylsulfide, or dimethyldisulfide. Additional benefits include a reduction in ripening times and extended shelf life of the cheese. Furthermore, Y. lipolytica has anti-listerial activity, and to inhibit the growth of Bacillus cereus and green mold ( Harzevili , 2014).

11. Conclusion From all the above, we can retain that microorganisms are living beings that interact with one another giving rise to various types of biological interaction, some of which, such as synergy and antagonism, are used in the biological field a nd specifically in Food industries . These are two phenomena depending on their effects are exploited in particular in the production and protection of foodstuffs.

12. References Laiño , J.E., Juarez del Valle, M., Savoy de Giori , G., LeBlanc, J.G., 2014. Applicability of a Lactobacillus amylovorus strain as co-culture for natural folate bio-enrichment of fermented milk. Int. J. Food Microbiol . 191, 10–16. Smid , E.J., Lacroix , C., 2013. Microbe–microbe interactions in mixed culture food fermentations. Curr . Opin . Biotechnol . 24, 148–154. Arioli , S., et al. (2016). "Streptococcus thermophilus urease activity boosts Lactobacillus delbrueckii subsp. bulgaricus homolactic fermentation." Int J Food Microbiol . Canan Öztoprak , 2016. Mikroorganizmaların beslenmesi ve gelişimi Harzevili , F. D. (2014). Biotechnological Applications of the Yeast Yarrowia lipolytica .