Samples of sour cassava starch wastewater were used for the quantification. The fermentation was carried out by two methods: one traditional and one modified (Marcon et al., 2006), between November 2011 and February 2012, in ten 20 L capacity highdensity polyethylene tanks. To each tank 10 L of water and 2.5 kg of commercial cassava starch previously homogenised in 1:4 (w/v) (starch/water) (traditional method) were added. To half of the tanks (five), 0.5% glucose corn syrup (Mix, São Paulo, Brazil) (modified method) was added together with the cassava starch suspension at the beginning of the process.