NOVELTY - Method (M1) for producing biological oil involves growing microorganism of kingdom stramenopile by heterotrophic fermentation using feedstock comprising cellulose as carbon source, where 11-99% of unsaturated fatty acids in the biological oil are polyunsaturated fatty acids.    USE - The method (M1) is useful for producing biological oil for producing biodiesel, jet biofuel, lipid-based biofuel and fuel additives, and in food, beverages, energy drinks, yogurt and pancake mixes, and nutritional and pharmaceutical products.    ADVANTAGE - The method is more scalable and sustainable, and cost-effectively and simply produces biodiesel that is inexpensive compared to seed-oil biodiesel or photosynthetic algal biodiesel.    DETAILED DESCRIPTION - Method (M1) for producing biological oil involves (a) growing microorganism of kingdom stramenopile by heterotrophic fermentation using feedstock comprising cellulose as carbon source, where 11-99% of unsaturated fatty acids in the biological oil are polyunsaturated fatty acids, (b) simultaneously or sequentially growing two or more microorganisms by heterotrophic fermentation using feedstock comprising cellulose as carbon source, where the one or more microorganisms are capable of saccharifying the cellulose, or (c) growing microorganism by heterotrophic fermentation in a nonsterile fermentor. INDEPENDENT CLAIMS are included for the following:    (1) method (M2) for producing biodiesel, involves (a) performing the above method (M1) to produce biological oil, and transesterifying the biological oil to produce biodiesel, (b) growing microorganism in nonsterile fermentor to produce biological oil and transesterifying biological oil to produce biodiesel, (c) growing microorganism using nutrients comprising recycled media to produce biological oil and transesterifying the biological oil to produce biodiesel, or (d) growing microorganism using fermentation system comprising continuous seed stage and lipid-production stage to produce biological oil and transesterifying the biological oil to produce biodiesel;    (2) method (M3) for producing jet biofuel involves (a) performing the above method (M1) to produce biological oil, and cracking the biological oil to produce jet biofuel, (b) growing microorganism in nonsterile fermentor to produce biological oil, and cracking the biological oil to produce jet biofuel, or (c) growing microorganism using fermentation system comprising continuous seed stage and lipid-production stage to produce biological oil, and cracking the biological oil to produce jet biofuel; and    (3) lipid-based biofuel composition comprising 1-75 wt.% of alkyl esters of long chain fatty acids having 20C or more.