The use of agriculture excess as substrate in industrial fermentations became an interesting alternative to reduce production costs and to reduce negative environmental impact caused by the disposal of these products. In this work, a kinetic study of mannitol production using cashew apple juice as substrate was studied. The carbohydrates of cashew apple juice are glucose and fructose. Sucrose addition favored the yield of mannitol (85%) at the expense of lower productivity. The best results were obtained applying only cashew apple juice as substrate, containing 50 g L(-1) of total reducing sugar (28 g L(-1) of fructose), yielding 18 g L(-1) of mannitol with 67% of fructose conversion into mannitol and productivity of 1.8 g L(-1) h(-1).