Microbiology and biochemistry of fermentation

Fermentation is a biological process in which microorganisms convert organic material, producing metabolites that make food more durable, more digestible, and more flavorful. At the core of this process are microbial communities of lactic acid bacteria, yeasts, molds, and other beneficial microbes. These organisms do not operate randomly, but follow precise biochemical processes that have evolved over millions of years.

The main players: Microorganisms in the service of refinement

In fermentation, certain groups of microbes dominate, depending on the medium, environment, and target product. Lactic acid bacteria such as Lactobacillus plantarum , Leuconostoc mesenteroides , or Pediococcus pentosaceus ferment sugar into lactic acid, lowering the pH and creating an environment in which pathogens can hardly survive. Yeasts such as Saccharomyces cerevisiae convert sugar into alcohol and carbon dioxide. Molds such as Aspergillus oryzae or Penicillium camemberti enzymatically break down complex macronutrients.

These microorganisms often form complex biofilms or symbiotic associations in which they stabilize, protect, and regulate each other's activity. The microbial dynamics in a fermentation are not a static process, but rather a finely balanced ecological interplay.

The biochemical basics: Fermentation as a conversion reaction

Fermentation is essentially a form of anaerobic energy production. It involves the degradation of sugar, starch, or other fermentable substrates without oxygen into smaller molecules such as lactic acid, ethanol, acetic acid, carbon dioxide, or butyric acid. These reactions alter the environment, create preservation, and open up a wealth of new flavors and textures.

In addition to the main products, bioactive by-products such as short-chain fatty acids, vitamins (e.g., vitamin K2, B12 in certain ferments), bioavailable minerals, and peptides with potentially probiotic effects are produced. Enzymatic pre-digestion of complex structures such as cellulose, lectins, or antinutrients significantly increases the bioavailability and tolerability of many foods.

Understanding and controlling microbial ecosystems

A successful ferment is the result of microbial selection. Temperature, salinity, oxygen availability, pH, and starting substrate act as ecological filters. Understanding how to specifically influence these parameters allows you to control microbial colonization. This results in safe, stable, and tasty ferments with high health benefits.

Modern fermentation practices utilize this knowledge to specifically promote cultures or guide natural spontaneous fermentations in a desired direction. Today, controlled fermentation combines traditional craftsmanship with microbiological precision.

Conclusion

Fermentation is not an accident, but rather a controlled biochemistry process. It is based on millennia-old empirical knowledge that can now be precisely explained by modern microbiology, ecology, and biochemistry. Fermenters create a microbial work of art. Each batch is a living system that not only improves flavor and shelf life, but can also actively contribute to health.