Lysozyme
An enzyme that suppresses lactic bacteria, delaying or blocking malolactic.
Typical dose
About 250 to 500 mg/L to delay malolactic, toward the top of that to inhibit it.
When to add it
Into must or young wine, before or in place of malolactic.
Legal limit
No specific limit that this reference states. Additions are still governed by the treating-materials rules where you make wine, so check them.
Vegan
No. Animal-derived, and usually an allergen to declare, so it rules out a vegan label and needs care on the ingredients list.
In practice
Dissolves the cell walls of gram-positive lactic bacteria, so it holds back malolactic in a fresh white you want crisp, or protects a stuck red from spoilage before you restart it. It does nothing to yeast, Brettanomyces or acetobacter, and bentonite strips it back out. It is an egg-white protein, which matters for allergen labelling.
Linked faults are the ones this addition either treats or, used wrongly, causes. The fault page says which, and whether it can be undone.
Others in antimicrobial and reduction treatment