Home Dartmouth Dissertations fan2004 1

Reference URL

To link to the entire object, paste this link in email, IM or document

To embed the entire object, paste this HTML in website

To link to this page, paste this link in email, IM or document

To embed this page, paste this HTML in website

Conversion of paper sludge to ethanol and analysis of selection based strain improvement for recombinant Saccharomyces cerevisiae expressing saccharolytic enzymes through continuous culture.

you wish to report:

Your comment:

Your Name:

Submit

Cancel

...

Call No.	Ph.D. 2004
Author	Fan, Zhiliang
Title	Conversion of paper sludge to ethanol and analysis of selection based strain improvement for recombinant Saccharomyces cerevisiae expressing saccharolytic enzymes through continuous culture.
Date	2004
Abstract	Paper sludge is the largest solid waste stream produced by pulp and paper industry, and is also an attractive feedstock for emergent technologies based on processing of cellulosic biomass featuring enzymatic hydrolysis. This study focuses on investigating conversion of paper sludge to ethanol under industrially relevant conditions. A solids-fed simultaneous saccharification and fermentation laboratory reactor system capable of aseptic, semi-continuous metered delivery of paper sludge was developed to carry out experiments with hydrolysis mediated by commercial cellulase preparations and fermentation of glucose to ethanol mediated by Saccharomyces cerevisiae. Economically recoverable concentrations of ethanol were produced, and good material balance closure was achieved. Decreasing feeding frequency (feed additions per residence time) was found to allow the cellulase loading to be decreased at least two-fold with no decrease in cellulose conversion. Although decreasing feeding frequency results in higher cost for mixing, this appears small relative to cellulase savings. Technical and economic viability of an industrial facility producing ethanol from paper sludge at Nexfor Fraser's Gorham paper mill was investigated under two scenarios. Scenario one is based on technology demonstrated at Dartmouth at lab scale. Scenario two is based on technology that is not yet demonstrated at Dartmouth, but is expected to be available for incorporation into a commercial plant with construction initiated in two years, assuming an aggressive development effort. Positive cashflow is realized for both scenarios, with gross income exceeding expenses by 0.8 fold in scenario 1 and 1.7 fold in scenario 2. Results showed the potential for attractive returns at a production scale if approximately 62% and 35% sharings of capital (e.g. from government sources) are available for scenario 1 and scenario 2 respectively. Total capital investment is projected to be <4 million, which is lower than possible for more typical cellulosic feedstocks. The possibility of selecting strains with improved ability to grow on cellulose whose growth is dependent on the extracellular enzymes through continuous culture was also analyzed. It was found that the extent to which selection for improved growth on non-native substrates is achievable depends on a variety of factors, such as the shape of the microorganism, the distance between the cell and the substrate surface, diffusivity of the substrate in the gap, the saturation constant of the growth equation etc.
Description	1 online resource (x, 194 leaves) : illustrations
Format	application/pdf
Advisor	Lynd, Lee R.
Subject	Cellulase -- Biotechnology. ; Hydrolysis. ; Paper industry -- Technological innovations. ; Biomass energy -- Economic aspects. ; Saccharomyces cerevisiae -- Genetics. ; Enzymes -- Industrial applications.
College	Thayer School of Engineering.
Issuing Body	Dartmouth Dissertations are made available through the Dartmouth Digital Library.
Degree	Thesis (Ph.D)--Dartmouth College.
Copyright	In Copyright. This material is protected by copyright and/or related rights. You are free to use this material in any way that is permitted by copyright law that applies to your use. For other uses, you need to obtain permission from the rights-holder(s). http://rightsstatements.org/page/InC/1.0/
DOI	https://doi.org/10.1349/ddlp.3075

Find results with:

Searching collections:

Home Dartmouth Dissertations fan2004 1

Conversion of paper sludge to ethanol and analysis of selection based strain improvement for recombinant Saccharomyces cerevisiae expressing saccharolytic enzymes through continuous culture.

Object Description

Description

Conversion of paper sludge to ethanol and analysis of...

Conversion of paper sludge to ethanol and analysis of...

	All
	Pages Enter page numbers or page ranges separated by commas. For example: 1,3,5-12