Lagfaser

Lagfaser, the plural form of lagfase, refers to the initial period after inoculation of microorganisms into a new growth medium during which cell division is minimal or not detectable. Lagfaser describes one or more lag phases observed in growth curves. During this phase, cells adjust to their surroundings and prepare for active growth rather than colony expansion.

Cellular processes in lagfaser include induction of metabolic pathways, synthesis of transport proteins and enzymes required to utilize available substrates, repair of damaged components, and reorganization of cellular structures. The duration of lagfaser varies widely among species and conditions, ranging from minutes to several hours. Factors influencing lag time include the physiological state of the inoculum (e.g., stationary vs. exponential phase), nutrient richness, temperature, pH, oxygen availability, and the presence of inhibitors or stress.

Growth resumes at the end of lagfaser as cells begin to replicate, entering the exponential phase. In growth curve analysis, lag time is a key parameter and is often described by models such as Gompertz or Baranyi. Measurements typically rely on optical density, viable counts, or substrate uptake rates. Lagfaser are relevant in food microbiology, biotechnology, and clinical settings because they affect process timing, product quality, and contamination risk. Practical approaches to modulate lag include pre-adaptation of cultures, adjusting inoculum conditions, and controlling environmental factors to shorten or extend the lag as needed.