The mesocarp of the babassu coconut, that represents 23% of the fruit weight, is the source of an amylaceous flour containing approximately 50% (w/w) starch. The mechanical processing of the coconut produces the babassu flour, which is a mixture of small starch particles and fibers. This work reports a series of experiments carried out, in an ethanol production industrial plant, to investigate the effect of the following parameters and operation conditions on the conversion yield of starch to dextrose: specific amount of the enzyme alpha-amylase, gelatinization procedure, fibers content, specific amount of calcium oxide and raw hour comminution. The results show that, among the process modifications investigated, hour comminution is essential to raise the industrial conversion yield from 90% to 97%.