Optimization of acid pretreatment for enzymatic saccharification of waste office paper

Date

10-2010

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Veronica P. Migo

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Abstract

The study was performed to determine the optimum conditions needed for the pretreatment of office waste paper to increase the yield of its enzymatic saccharification as a prerequisite for alcoholic fermentation to produce ethanol. Compositional analysis was performed to evaluate the parameters of the components of the substrate and determine the pretreatment process suitable for it. Analysis show that the substrate has 14.93 ± 0.04 % ash, 4.55 ± 0.75% moisture, 2.41 ± 0.05% total extractives, 0.77 ± 0.19% total lignin, and 76.14 ± 2.20% total sugars by mass. The sample is mostly cellulosic and almost free of lignin in the structure, although there are other components of significant percentage composition which could affect the pretreatment process. Optimization of the acid pretreatment was performed using the Response Surface Methodology. The factors that were optimized are the incubation time, temperature, and concentration of the acid. Using the program DesignExpert 7 which uses the RSM procedure, Box-Behnken Design, 17 different sets of conditions were generated, with basis on the 12 random corner points and 5 random center points within the design space. The responses, or the indices of performance, are the loss in the filtrate after pretreatment, determined as total sugars using the phenol-sulfuric acid method, and the reducing sugar content of the filtrate after saccharification, determined as total reducing sugars using Nelson’s Method. The goals of the optimization procedure were compared based on the degree of constraints. For the first goal, where the sugar yield in the saccharification process was maximized regardless of the effect of other factors, there were 33 solutions ranked by their statistical desirability. In the second goal, where the sugar yield after saccharification was maximized, while the sugar loss in the pretreatment was minimized, there were 8 solutions generated by the program as the optimum values. In the third goal, where the sugar yield in the saccharification is maximized while all the factors in the pretreatment (time, temperature, acid concentration), including the sugar loss were minimized, 15 solutions were generated. The solutions were compared according to their statistical desirability, and found out that the solutions are statistically different for each of the goals. In the evaluation of the model and the procedure using statistical analysis, the model equation %Reducing Sugars = -51.52802371 + 13.03948997A + 1.74339882B - 1.583576227C - 0.011562552AB - 0.087179685AC + 0.018166925471864BC - 1.523589666A2 -0.013125138B2 + 0.002155074C2, where A- Concentration, B-Temperature, and C-Time, was generated. The model is significant, suggesting that the model can be used to correctly predict the response given the set of conditions within the design space, and analysis of variance also show that the factors time, temperature, acid concentration, and sugar loss affect the yield of sugar conversion of the substrate.

Language

English

LC Subject

Waste products as fuel

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2010 C4 M37

Document Type

Thesis

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