In a series of laboratory experiments, the rice straw was pretreated with sodium chlorite followed by biological treatments for bioethanol production. Both Aspergillus niger NRRL-3 and Trichoderma reesei NRRL-11460 were successfully grown on basal medium enriched with 1 % (w/v) of untreated rice straw and either cellulose-, hemicellulose- or holocellulose- by products of the straw hydrolysis. Appreciable amounts of extracellular enzymes were produced in these very special cultivation media. Among tested enzymes, xylanase was produced in the highest quantity (40.54 IU ml-1), carboxymethyl cellulase ranked the second (3.35 IU ml-1) while cellobiase and filter paper-ase scantly detected. Holocellulose seemed the pioneer byproduct supporting the enzyme production followed by cellulose, hemicellulose was the inferior in this respect. Apart from substrate and enzyme type, the fungus T. ressei over came A. niger for enzyme formation. The enzymatic activity of the introduced inocula obviously reflected on the producing sugar pools. Compared to others, T. reesei acted more actively, the produced reducing sugars could be arranged in the descending order: 2.62 mg ml-1 (T. ressei) > 2.52mg ml-1 (A. niger + T. ressei) > 1.10 mg ml-1 (A. niger). The optimal level of reducing sugars was scored at the 8th day-interval in hollocellulose-amended fungal culture medium, the respective quantities of 22.90, 20.30 and 13.22 were produced in the presence of T. reesei, mixed inoculum and A. niger. Raising the ammonium sulphate over the recommended level in fungal culture medium significantly stimulated sugar production. Simultaneous saccharification and fermentation (SSF) of cellulose by Saccharomyces cerevisiae and cellulases was evaluated in three basal media. Ammonium sulfate-enriched medium was the pionerric compared to others. The impact of some SSF conditions (cellulose concentration, enzyme quantity, incubation period and shaking rate) on ethanol production was discussed.