Hydrolysis of cellulose from sugarcane bagasse by cellulases from marine-derived fungi strains

Four marine-derived fungi strains-Penicillium citrinum CBMAI 1186, Aspergillus sydowii CBMAI 934, Aspergillus sydowii CBMAI 935 and Mucor racemosus CBMAI 847-were studied as potential microbial producers of cellulases under solid-state fermentation. The cultivation parameters (time, pH and temperature) and the performance of the cellulases in the hydrolysis of cellulose from sugarcane bagasse were evaluated. The best cultivation time in solid-state fermentation for producing cellulases was 3 days for all of the strains except for A. sydowii CBMAI 934, which exhibited its highest filter paper activity (FPU) after 7 days. After optimizing pH and temperature, activities of 0.73, 1.9, 2.4 and 1.3 FPU g−1 (of substrate) were obtained for A. sydowii CBMAI 935, A. sydowii CBMAI 934, M. racemosus CBMAI 847 and P. citrinum CBMAI 1186, respectively. The hydrolysis of cellulose was studied using rind and pith fractions of sugarcane bagasse, with and without alkali pretreatment. Independent of the fungi strains, untreated bagasse was resistant to saccharification. After the treatment, the degree of saccharification was 78% for A. sydowii CBMAI 934 and 24% for M. racemosus CBMAI 847. The different anatomical and morphological characteristics of the rind and pith cells influenced the saccharification by cellulases for the different marine fungi strains. The hydrolysis by cellulases from A. sydowii CBMAI 934 produced 56% and 81% saccharification in the rind and pith, respectively. This fungus strain exhibits significant potential for the production of fermentable sugars resulting from the hydrolysis of cellulose from sugarcane bagasse, mainly after pretreatment with NaOH solution.