Agriculture surplus were used as substrates to synthesize gamma-aminobutyric acid (GABA) by Lactobacillus plantarum DSM19463 for the manufacture of a functional beverage or as a novel application for dermatological purposes. Dilution of the grape must to 1 or 4% (w/v) of total carbohydrates favored higher cell yield and synthesis of GABA with respect to whey milk. Optimal conditions for synthesizing GABA in grape must were: initial pH 6.0, initial cell density of Log 7.0 cfu/mL, and addition of 18.4 mM L-glutamate. L. plantarum DSM19463 synthesized 4.83 mM of GABA during fermentation at 30 degrees C for 72 h. The fermented grape must also contain various levels of niacin, free minerals, and polyphenols, and Log 10.0 cfu/g of viable cells of L. plantarum DSM19463. Freeze dried preparation of grape must was applied to the SkinEthic(R) Reconstructed Human Epidermis or multi-layer human skin model (FT-skin tissue). The effect on transcriptional regulation of human beta-defensin-2 (HBD-2), hyaluronan synthase (HAS1), filaggrin (FGR), and involucrin genes was assayed through RT-PCR. Compared to GABA used as pure chemical compound, the up-regulation HBD-2 was similar while the effect on the expression of HAS1 and FGR genes was higher.