S. cerevisiae TISTR 5048 and E. aerogenes TISTR 1468 were obtained from Thailand Institute of Scientific and Technology Research (TISTR), Thailand. The culture of S. cerevisiae was maintained on MPDY (malt extract 0.3%, peptone 0.5%, yeast extract 0.3% and dextrose 2%) agar (1.5%) slant at 4oC [1]. E. aerogenes was cultivated on Luria-Bertani (LB) agar. Each inoculum was prepared by inoculating the slant culture into 25 mL of the sterile liquid medium in 100 mL conical flask and growing it on a rotary shaker (100 rpm) for 48 h. 20% (v/v) inoculums (6 x 104 cell/mL) was inoculated into 100 mL sterile pineapple peel hydrolysate in 250 mL conical flask and was incubated up to 5 days under stationary conditions. All the state experiments were conducted at pH 5.0 and 30oC [1].