Update 04_dfba.md

docs/04_dfba.md

@@ -57,9 +57,9 @@ Governing Equation:
 
 where:
 
-- $X$ is the biomass concentration [g/L].
-- $D$ is the dilution rate [h^{-1}], defined as the volumetric feed flow rate divided by the reactor volume.
-- $\mu$ is the specific growth rate [h^{-1}], obtained from the metabolic model or flux balance analysis.
+- $X$ is the biomass concentration $[g/L]$.
+- $D$ is the dilution rate $[h^{-1}]$, defined as the volumetric feed flow rate divided by the reactor volume.
+- $\mu$ is the specific growth rate $[h^{-1}]$, obtained from the metabolic model or flux balance analysis.
 
 In this balance, there is **no inflow of cells** (i.e., feed does not contain biomass), so the only sources and sinks are (a) the **growth** of biomass within the reactor and (b) the **washout** of cells at the outflow. The accumulation term is therefore governed by the net of growth minus outflow.