diff --git a/ecoli/processes/metabolism.py b/ecoli/processes/metabolism.py
index 4a1c653f5..44c01b761 100644
--- a/ecoli/processes/metabolism.py
+++ b/ecoli/processes/metabolism.py
@@ -95,6 +95,7 @@ class Metabolism(Step):
         "linked_metabolites": None,
         "aa_exchange_names": [],
         "removed_aa_uptake": [],
+        "set_reaction_bounds": {},  # In form: {FBA_RXN_ID:[lb,ub]} (reaction must match FBA basis)
         "seed": 0,
         # TODO: For testing, remove later (perhaps after modifying sim data)
         "reduce_murein_objective": False,
@@ -532,6 +533,27 @@ def next_update(self, timestep, states):
             catalyst_counts, counts_to_molar, coefficient, translation_gtp
         )
 
+        # Set reaction limits from config options
+        config_reaction_bounds = self.parameters.get("set_reaction_bounds", {})
+        for rxn, bounds in config_reaction_bounds.items():
+            if rxn not in self.fba_reaction_ids:
+                raise ValueError(
+                    f"set_reaction_bounds: reaction '{rxn}' not found in FBA reaction IDs"
+                )
+            try:
+                lower_bound, upper_bound = bounds
+            except (TypeError, ValueError) as e:
+                raise ValueError(
+                    f"set_reaction_bounds for '{rxn}' must be a 2-item sequence [lower, upper], got: {bounds!r}"
+                ) from e
+            if lower_bound > upper_bound:
+                raise ValueError(
+                    f"set_reaction_bounds for '{rxn}' has lower_bound > upper_bound ({lower_bound} > {upper_bound})"
+                )
+            self.model.fba.setReactionFluxBounds(
+                rxn, lowerBounds=lower_bound, upperBounds=upper_bound
+            )
+
         # Constrain reactions based on targets
         targets, upper_targets, lower_targets = self.model.set_reaction_targets(
             kinetic_enzyme_counts,
@@ -1149,5 +1171,31 @@ def test_metabolism_listener():
     assert isinstance(reaction_fluxes[1], list)
 
 
+def test_set_reaction_bounds_config():
+    from ecoli.experiments.ecoli_master_sim import EcoliSim
+    import pytest
+
+    sim = EcoliSim.from_file()
+    sim.max_duration = 2
+    sim.build_ecoli()
+
+    metabolism = sim.ecoli.processes["agents"]["0"]["ecoli-metabolism"]
+
+    # test invalid configuration: reaction not in FBA reaction IDs
+    metabolism.parameters["set_reaction_bounds"] = {"NOT-A-REAL-RXN": [0, 1]}
+    with pytest.raises(ValueError, match="not found in FBA reaction IDs"):
+        sim.run()
+
+    # test valid configuration
+    rxn_id = metabolism.fba_reaction_ids[0]
+    metabolism.parameters["set_reaction_bounds"] = {rxn_id: [0.0, 0.0]}
+    sim.run()
+    data = sim.query()
+    reaction_fluxes = data["agents"]["0"]["listeners"]["fba_results"]["reaction_fluxes"]
+    rxn_idx = metabolism.fba_reaction_ids.index(rxn_id)
+    for fluxes_at_t in reaction_fluxes:
+        assert fluxes_at_t[rxn_idx] == pytest.approx(0.0, abs=1e-6)
+
+
 if __name__ == "__main__":
     test_metabolism_listener()