Trehalose accumulation from starch by Saccharomycopsis fibuligera sdu was examined in 300-ml shaken flask culture and Biostat B(2) 2-1 fermentation. In the 300-ml flask, 16.5% (w/w) trehalose accumulated in the yeast cells (cell dry weight) was observed with 100-ml medium shaken at 200 rpm for 50 h at 30 degrees C. We found that 1.0% soluble starch in the medium was most suitable for trehalose accumulation by this yeast strain. In the Biostat B(2) 2-1 fermentor, 18.0% (w/w) trehalose accumulated in the yeast cells (cell dry weight) was observed within 48 h of fermentation when agitation speed was 200 rpm. The trehalose obtained from the yeast cells was identical to standard trehalose from Sigma based on the analysis results of High-Performance Exchange Anionic Chromatography (HPEAC).