Ethanol made from non-food biological sources is called bioethanol. Ethanol or regular alcohol with the formula C2H5-OH can be made using inexpensive cellulosic sources, such as straw, wood chips, agricultural residues, whey, or relatively valuable carbon sources such as sugar beet molasses or sugarcane molasses. Or provided quite valuable carbon sources such as sugar and starch. Agricultural wastes are mainly composed of cellulose, the most abundant natural organic matter. It is estimated that ten trillion tons of it are generated every year on the earth's surface. It is estimated that biosynthesis generates ten trillion tons of it every year on the earth's surface. In this research study, while introducing the sources of bioethanol, we discussed its use as a green fuel in cars.

Bioethanol is a second generation biofuel that has recently received attention due to limited fossil fuel resources and air pollution cause of fossil fuels. In this study production of bioethanol from lignocellulosic material of corn fiber in a membrane bioreactor was investigated. Acid pretreatment was used to increase the fraction of cellulose to 41%. The strain of saccharomyces cerevisiae was used as yeast. In most previous works the experimens have been performed in batch systems, whereas in this study simultaneous saccharification and fermentation (SSF) were performed in a continuous ultrafilteration membrane reactor, where the product is removed to prevent the inhibitory effect of the product on bioethanol production yield and enzyme deactivation. Experimental design and optimization was carried out by Design Expert software. The optimum conditions were determined to be: temperature (38.5°C), agitation speed (631.2 rpm) and surfactant concentration (0.08%v/v). Under these conditions the predicted ethanol yield was 87.8% and the actual experimental value was 84.2%.

Dead yeast cells are an abundant residue of the Brazilian ethanol industry and the industries still don’t have a proper or desirable destiny for all these cells, which means tons of vitamins and proteins that have not a major end. In the other hand, heavy metal residues are a problem, especially for leather industry, where Brazil is also a great producer. In this work, dead yeast cells were used to evaluate cadmium bio sorption samples. Results have shown that dried dead yeast cells at 20 % (W/V) immobilized in Na-alginate beads 0.5 % can be an efficient alternative for the capture of cadmium. The average bio sorption rate was 122.10 mg Cd/ g of dry biomass in comparison to the control using only the Na-alginate beads 0.5 % where the bio sorption rate achieved 57.29 mg Cd/g of dry biomass. This research opens wide opportunities to allies two major residues created in Brazilian industries with a noble end for the industries it selves as for the environment.