Thesis (B.S.) -- Cagayan State University, 2024.
Includes bibliographical references.

This paper seeks to compare the effects of sodium hydroxide, oxalic acid, and two- stage (acid-alkali) pretreatment on the brix degree and percent ethanol yield from Napier grass. The substrate underwent simultaneous saccharification and fermentation process using 10 grams of the substrate, 2 grams of cellulase, 100 mL of buffer solution, 100 mL of nutrient solution, and 10 mL of yeast solution. Both pretreated and untreated samples were analyzed for Brix degree and ethanol content at 24, 48, and 72-hour intervals. In control samples, the brix degree was reduced from 5. 2 to 2.5 over 72 hours, with ethanol content ranging from 0.07% to 0. 33%. The one stage NaOH pretreatment enhanced the ethanol yield to the highest of 1. 19% with 1.0 M NaOH, and significantly decreasing the Brix degree. Ethanol yield was also enhanced by oxalic acid pretreatment but to a lesser degree compared to NaOH with the maximum yield of 0. 38% at 2% w/v oxalic acid. In the two-stage pretreatment (oxalic acid followed by NaOH pretreatment), the highest ethanol yield was 0.07% for the combination of 2. 0% OxA and 0. 8 M NaOH. Although the Brix degree reduction was almost the same for both two-stage and one-stage NaOH pretreatment, the ethanol yield from the former process was lower in general. This implies that single-stage NaOH pretreatment is the best method to increase ethanol yield of the Napier grass.

Keywords: two-stage pretreatment, brix degree, percent ethanol yield, simultaneous saccharification and fermentation.