Parametric Study on the Dilute Acetic Acid Hydrolysis of Rain Tree (Albizia saman (Jacq.) Merr.) Pods for Bioethanol Production

Author : Magsanoc, Samara Casey de Mesa
Major Adviser : Sumagang, Maria Victoria M.
Committee Members : Migo, Veronica P.; Arocena, Rhebner E.
Year : 2018
Month : June
Type : Thesis
Degree: BS
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Lignocellulosic biomass are non-food crops or agricultural wastes that are rich in cellulose. The celluloses can be hydrolyzed and turned into fermentable sugars. The pods of the rain tree are rich in lignin and celluloses, making them a viable feedstock for bioethanol production. After the collection, particle size reduction by grinding, and delignification of the pods using 1% NaOH, hydrolysis was conducted at a constant pressure and temperature of 121 °C using an oil bath set-up. The acid concentration (1, 3, 5%), solid-acid ratio (5, 10, 15% w/v), and hydrolysis time (10, 20, 30 mins), were varied for ground pods with and without seeds to determine their individual and interactive effects on the amount of sugars produced via hydrolysis. With an a = 0.05, solid-acid ratio was found to be the factor with the most significant effect, which is expected since more biomass would imply more available celluloses to be hydrolyzed into sugars. Further, it was found that the highest reducing sugar yield of 1340.4 ppm was found to be from 5% acetic acid concentration, 15% solid to acid ratio, and 30 mins of hydrolysis time for delignified pods without seeds. Preliminary fermentation by Saccharomyces cerevisiae showed that bioethanol can be produced from the hydrolysates, with an average of 40.87% reduction in the reducing sugars, corresponding to an average of 5.858% of ethanol produced after 24 hours of fermentation. However, since the presence of seeds had significant effect on the reducing interaction of the acetic acid concentration and solid to acid ratio, it is recommended to retain the seeds during hydrolysis.

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