Comparison of lactic acid bacteria (LAB) inhibitors for control of malolactic fermentation (MLF). MIC, minimal inhibitory concentration.
| Inhibitor | Mode of action | Effective concentration/conditions | Advantages | Limitations/drawbacks | Source |
|---|---|---|---|---|---|
| Molecular SO2 | Disrupts LAB metabolic processes, antimicrobial against yeast and bacteria | Effectiveness declines with higher pH, requires careful dosing | Widely available, dual antimicrobial and antioxidant role, reported fruity aromatic intensity | Can cause allergic reactions, may lead to hydrogen sulfide formation, less effective at high pH | Fang and Dalmasso 1993, Gerbaux et al. 1997, Divol et al. 2012, Quirós et al. 2012, Prusova et al. 2024 |
| Lysozyme | Enzyme hydrolyzing Gram-positive bacterial cell walls, leading to lysis | 500 mg/L in must inhibited MLF, 250 mg/L post-MLF stabilized wines | Effective SO2 alternative, selective for LAB | May cause haze, phenol precipitation, color loss in reds; heat instability in whites; some Pediococcus spp. strains exhibit resistance | Lerm et al. 2010, Bartowsky et al. 2004, Coulon et al. 2012, Bartowksy and Krieger-Weber 2020 |
| Fumaric acid | Inhibits LAB metabolism, slight acidification | ≥300 mg/L prevented MLF, 600 mg/L halted ongoing MLF | Enhances freshness and acidity perception, preserves phenolic/color stability, reduces SO2 needs | Efficacy in very high pH wines not fully established, limited pH effect, low solubility (~15 g/L in wine) | Fang and Dalmasso 1993, Morata et al. 2019, Gancel et al. 2022, Prusova et al. 2024 |
| Nisin | Polypeptide bacteriocin, disrupts cell wall synthesis and ion channels | MIC ~0.024 mg/L for Oenococcus oeni; 50 mg/L reduced SO2 requirements | Very potent against LAB, synergistic with SO2, not known to affect sensory properties | While generally recognized as safe as a food additive, nisin is not yet approved for use in winemaking in all regions. | Daeschel et al. 1991, Rojo-Bezares et al. 2007, Fernández-Pérez et al. 2018 |
| Chitosan | Biopolymer disrupts Gram-positive microbial growth, also antioxidant | Applied during fermentation and aging | Natural product, antimicrobial, controls oxidation, limited sensory effects | May alter yeast dynamics, effectiveness as an MLF inhibitor depends on target LAB strain and dosage, found ineffective in some cases at inhibiting MLF during longer aging periods | Scansani et al. 2020, Miot-Sertier et al. 2022, Moulis et al. 2023, Prusova et al. 2024 |