A novel recombinant oligogalacturonide lyase from Klebsiella variicola promotes pectin degradation and enhances aroma formation in tobacco leaves

Microbial enzymes can be exploited to improve the sensory quality and reduce the harmful effects of tobacco-originated compounds in tobacco-derived products. In this study, a novel oligogalacturonide lyase (OGL) gene from Klebsiella variicola GB3 was cloned and heterologously expressed in Escherichia coli BL21(DE3). The recombinant enzyme was purified to a protein concentration of 18.63 mg/mL. OGL exhibited the highest activity toward tetragalacturonic acid (GalA 4 ), with kinetic parameters of K m = 3.89 ± 0.18 mM and V max = 36.41 ± 1.20 μmol/min/mg, and optimal catalytic activity at 45 °C and pH 6.0. The enzyme remained stable over a moderate temperature range (30–40 °C) and a broad pH range (6.0–8.0), while Ca 2+ significantly enhanced its catalytic activity. The treatment with 1% OGL degraded approximately 32.18% of tobacco pectin, accompanied by significant increases in galacturonic acid (39.86%) and oligogalacturonides (403.85%). Sensory evaluation indicated improved aroma quality, increased smoothness, and reduced irritation in OGL-treated tobacco strands. GC-MS analysis confirmed that OGL treatment significantly enhanced the production of key aroma compounds, including norisoprenoids, furans, and terpenoids, while reducing undesirable off-flavor compounds. Collectively, these results indicate that OGL efficiently degrades tobacco pectin, promotes the release of aroma precursors, and the formation of key flavor compounds. This study highlights the potential of OGL as a promising biocatalyst for improving aroma quality and enabling the value-added bioconversion of tobacco resources.