<p>Grape pomace, a key winemaking by-product, is rich in bioactive compounds but largely underutilized. When not discarded, it is mainly used for low-value applications, though its potential for adsorption or immobilization has been shown. This study explores its dual application by evaluating the efficiency of simultaneous fining and malolactic fermentation of wine using lactic acid bacteria immobilized on grape pomace. Grape pomace powder was used to immobilize <i>Oenococcus oeni</i> and <i>Lactiplantibacillus plantarum</i> cells, evaluating the effect of grape pomace type (red/white) and freeze-drying of the immobilized bacteria on both applications. Efficiency was assessed by measuring pH, malic acid consumption rate, anthocyanin and tannin removal rate, total polyphenol index, and color parameters. Immobilization efficiency of lactic acid bacteria reached values of up to 93.5% for <i>O. oeni</i> and 95.1% for <i>L. plantarum</i>, while the former showed higher pH increase during malolactic fermentation despite the higher residual malic acid levels. Fining with grape pomace reduced anthocyanin and tannin content by up to 47% and 46.7%, respectively, whereas freeze-drying enhanced fining efficiency, particularly for tannin removal, and significantly influenced wine color. To the best of our knowledge, this is the firststudy to demonstrate the use of grape pomace as a dual-function bioresource that simultaneouslyserves as a fining agent and as an immobilization carrier for lactic acid bacteria during wine malolacticfermentation. The findings provide valuable insights into the potential applications of grape pomace, contributing to the advancement of biotechnological processes in winemaking and offering new approaches for improving wine quality by adapting sustainable and chemical-free technologies.</p> Graphical Abstract <p></p>