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Manganese as a controlling factor in mixed cultures of Lactobacillus plantarum and Enterobacteriaceae
B Bruyneel1, M Vande Woestyne, W Verstraete
1Laboratory of Microbial Ecology, State University of Gent, Belgium.
Abstract:
Addition of manganese, at levels of 50 ppm, to a liquid growth medium simulating adverse silage conditions had no effect on the growth or on the fermentation pattern of Enterobacter cloacae and Proteus vulgaris. Yet, the manganese strongly enhanced the growth of Lactobacillus plantarum. Co-cultures of L. plantarum and E. cloacae or P. vulgaris were, by addition of manganese ions, significantly altered in the favour of the former. This finding can be of use in mixed cultures where Enterobacteriaceae act as spoiler microorganisms.
Insights
Manganese addition to silage media did not affect Enterobacter cloacae or Proteus vulgaris growth. However, manganese significantly boosted Lactobacillus plantarum growth and favored it in mixed cultures, suggesting a role in controlling spoilage bacteria.
Area of Science:
- Microbiology
- Agricultural Science
- Food Science
Background:
- Enterobacteriaceae, such as Enterobacter cloacae and Proteus vulgaris, can act as spoilage microorganisms in silage.
- Lactobacillus plantarum is a beneficial lactic acid bacterium often used as a silage inoculant.
- Understanding microbial interactions and the effects of micronutrients in silage fermentation is crucial for improving silage quality.
Purpose of the Study:
- To investigate the effect of manganese on the growth of Enterobacter cloacae, Proteus vulgaris, and Lactobacillus plantarum.
- To determine the impact of manganese on the growth dynamics of co-cultures containing these bacteria.
- To explore the potential of manganese as a tool to modulate microbial populations in silage.
Main Methods:
- Culturing of pure strains of E. cloacae, P. vulgaris, and L. plantarum in liquid media simulating silage conditions.
- Addition of manganese (50 ppm) to the growth media.
- Analysis of growth patterns and fermentation characteristics.
- Co-culturing experiments with L. plantarum and either E. cloacae or P. vulgaris in the presence of manganese.
Main Results:
- Manganese at 50 ppm had no significant effect on the growth or fermentation of E. cloacae and P. vulgaris.
- Manganese strongly enhanced the growth of L. plantarum.
- Co-cultures showed a significant shift favoring L. plantarum in the presence of added manganese ions.
Conclusions:
- Manganese can selectively promote the growth of Lactobacillus plantarum over Enterobacteriaceae in simulated silage environments.
- This selective enhancement suggests manganese could be utilized to control spoilage by Enterobacteriaceae in mixed microbial cultures.
- The findings offer a potential strategy for improving silage fermentation by favoring beneficial bacteria and inhibiting detrimental ones.