Effect of fermented sea tangle on the alcohol dehydrogenase and acetaldehyde dehydrogenase in Saccharomyces cerevisiae

Sea tangle, a kind of brown seaweed, was fermented with Lactobacillus brevis BJ-20. The gamma-aminobutyric acid (GABA) content in fermented sea tangle (FST) was 5.56% (w/w) and GABA in total free amino acid of FST was 49.5%. The effect of FST on the enzyme activities and mRNA protein expression of alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) involved in alcohol metabolism in Saccharomyces cerevisiae was investigated. Yeast was cultured in YPD medium supplemented with different concentrations of FST powder [0, 0.4, 0.8, and 1.0% (w/v)] for 18 h. FST had no cytotoxic effect on the yeast growth. The highest activities and protein expressions of ADH and ALDH from the cell-free extracts of S. cerevisiae were evident with the 0.4% and 0.8% (w/v) FST-supplemented concentrations, respectively. The highest concentrations of GABA as well as minerals (Zn, Ca, and Mg) were found in the cell-free extracts of S. cerevisiae cultured in medium supplemented with 0.4% (w/v) FST. The levels of GABA, Zn, Ca, and Mg in S. cerevisiae were strongly correlated with the enzyme activities of ADH and ALDH in yeast. These results indicate that FST can enhance the enzyme activities and protein expression of ADH and ALDH in S. cerevisiae.