Eucheuma serra is a kind of red algae，belongs to Rhodophyta and has an annual production nearly 8 million metric tons. Eucheuma serra is regarded as a raw material for extracting carrageenan on industry, and its residue still with multiple functional compounds could recycle use. Thus, in this study, we used the residue (algae residue) after extracting the functional component of Eucheuma serra as a raw material, it treated with enzymatic hydrolysis to be more suitable as a substrate for lactate fermentation than that did by acid treatments. Four GRAS (generally recognized as safe) lactic acid bacteria were screened to ferment the algae residue. Among them, the lactic acid strain P2 (Lactobacillus lacti s) could utilize more total sugar and reducing sugar of algae residue, followed by strain F2 (Lactobacillus sakei) and strain P1 (Lactobacillus farciminis). The strain F1 (Pediococcus pentosaceus) is the less efficiency on lactic acid fermentation. In order to increase the ability of lactic acid fermentation, we combined the lactic acid strain and then - 1 - 1082440 1. fermented, the results shown that efficacy of fermentation on the group A (P2+P1) and the group C (P2+F2) were better than the other test groups. This result was consisted with the lactated fermentation, it did by single strain. In addition, adding 5% MSG (sodium glutamate) didn’t increase the effency on lactate fermentation of algae residue. Moreover, neither the single strain nor the combined strain of lactic acid bacterium had ability to increase production of gamma-aminobutyric acid (GABA) in lactate fermentations. However, the contents of GABA were increased 8.5 times on the 24 hrs fermentation by adjusting the fermented substrate formula, and the fermentation effect of lactate strain P1, P2, and combined strain P1+P2 were higher than the other test lactate strains. In summary, the residue after extracting the functional composition of Eucheuma serra treated with enzymatic hydrolysis, and then by adjusting the fermented substrate formula, that could enhance the production of GABA with functional properties for well-sleeping and stable-emotion on the lactate fermentation. Further studies will try to increase the yield of GABA by modifying the fermented formula of lactic acid fermentation, as the same time, to establish the scale production. In addition, the stability of the lactic acid fermented product in the intestine and the feasibility of commercialization are evaluated to facilitate the recycling used of industrial by-products and enhance the economic value chain.