Bioethanol production from pineapple waste

The increasing demands for energy consumption have affected the supply of fuels, thus depleting our natural resources and further causing oil prices to escalate. At present, alternative fuels are available in the market such as bioethanol and biodiesel. These fuels however are produced from resources that are competing with the food consumption therefore the need to discover new resources of alternative fuels are a necessity. This study focus on the production of bioethanol using pineapple wastes. The celluloses from pineapple wastes were converted to simple sugars using two types of hydrolysis namely, acid and enzymatic hydrolysis. Enzymatic hydrolysis was done as a preliminary experiment using cellulose enzymes derived from fungi Aspergillus niger and Trichoderma reesei. While acid hydrolysis made use of varying amounts of biomass namely, 100 grams, 150 grams and 200 grams of dried wastes submerged in different concentrations of sulfuric acid solutions. The sugar produced by both hydrolysis methods which was analyzed using UV spectrophotometer, were compared to know which of the two is more efficient in converting biomass to sugars. The enzymatic hydrolysis was found to be efficient in terms of percent conversion of cellulose to sugar. However, acid hydrolysis produced higher concentrations of sugar and is more economical than that of the enzymatic hydrolysis. Therefore, the study proceeded on using acid hydrolysis. Based on the results obtained from the acid hydrolysis experiment, the most efficient cellulose to sugar conversion was 55.32% with 100 grams of dried wastes in 10% sulfuric solution. The hydrolyzed solution obtained from the acid hydrolysis underwent fermentation with bakers yeast for three days. The ethanol concentrations were analyzed by means of gas chromatography using a thermal conductivity detector (GC-TCD). Based on the results obtained from the GC-TCD analysis, the highest ethanol concentration was from the fermentation of hydrolyzed 150 grams of biomass in 10% sulfuric acid solution which produced an ethanol concentration of 13.270 grams per liter. The results from the sugar analysis and GC analysis were optimized using a statistical program named MINITAB. The statistical analysis was done to optimize the best combinations of acid concentration and weight of biomass. The best combination generated from the program in terms of percent conversions of biomass to ethanol and sugar to ethanol, was of the 100 grams of dried pineapple wastes hydrolyzed in 10% sulfuric acid solution. While the best combination in terms of sugar and ethanol concentrations was from 200 grams of dried pineapple wastes hydrolyzed in 10% sulfuric acid solution