Conversion of Lignocelluloses into bioethanol utilizing hardwood sawdust used for pleurotus ostreatus cultivation

Date of Publication

2010

Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Chemical Engineering

College

Gokongwei College of Engineering

Department/Unit

Chemical Engineering

Thesis Adviser

Joseph Auresenia

Defense Panel Chair

Luis Frias Razon

Defense Panel Member

Josephine Q. Borja

Marylou Mora Uy

Abstract/Summary

In this study, hardwood sawdust substrate used for oyster mushroom cultivation was utilized as raw material for ethanol production. The cultivation of oyster mushroom was used as a pretreatment to degrade the lignin content of the raw material. The lignocelluloses in the raw material were converted to ethanol by concentrated sulfuric acid hydrolysis for an hour and simple fermentation for four days. The same experimentation process was also done using pure hardwood sawdust (uncultivated with oyster mushroom) in order to compare whether the oyster mushroom gave significant changes in sugar and ethanol yield. The hydrolysis process was optimized and the parameters varied were temperature, biomass concentration, and acid concentration. Taguchi Array was used to determine the conditions for the 9 runs of the experimentation.

The highest sugar and ethanol concentration were both obtained at run 1 (121C, 15% (v/v) acid concentration and 20% (w/v) biomass concentration). Comparing the results for sawdust substrate used for oyster mushroom cultivation and pure sawdust substrate, the sugar and ethanol concentration were higher for pure sawdust. The oyster mushroom may have helped in the degradation of lignin in the sawdust substrate cultivated with mushroom but also might have degraded some of the celluloses and hemicelluloses that affected the amount of lignocelluloses converted to fermentable sugars. The effect of the activity of the natural enzyme released by oyster mushroom had been proven that this white-rot fungi releases enzymes that can completely degrade the lignocellulosic material. It degrades lignin but at the same time releases enzymes that degrades hemicelluloses and cellulose such as the enzyme cellulase.

The optimum conditions depend upon the desired output. If a higher concentration of sugar, sugar yield percent, ethanol concentration for both raw materials, and high ethanol yield percent for the cultivated hardwood sawdust substrate used in growing mushroom would be desired, then based on the experiment the conditions for hydrolysis process can be performed at 121C, 15% (v/v) acid concentration and 20% (w/v) biomass concentration. But if a higher ethanol yield for the pure hardwood sawdust would be desired then the conditions for the hydrolysis can be performed at 121C, 15% (v/v) acid concentration and 10% (w/v) biomass concentration.

In conclusion, having a high concentration is better than having good yield percent considering that using pure hardwood sawdust gave a higher concentration than hardwood sawdust used in cultivating oyster mushrooms. The effect of the mushroom had degraded the lignocellulosic component that had caused a trade-off in which the sawdust was instead used in producing oyster mushroom than having high ethanol concentration. In ethanol production having a high concentration in terms of its purity is better to achieve rather than having a good yield percent making the pure hardwood sawdust better to use.

Abstract Format

html

Language

English

Format

Print

Accession Number

TU15948

Shelf Location

Archives, The Learning Commons, 12F, Henry Sy Sr. Hall

Physical Description

xii, 118 leaves : ill. ; 28 cm.

Keywords

Lignocellulose; Biomass energy; Pleurotus; Wood waste

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