Table Of ContentBioethanol and Natural
Resources
Bioethanol and Natural
Resources
Substrates, Chemistry and
Engineered Systems
Ruben Michael Ceballos
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Library of Congress Cataloging‑in‑Publication Data
Names: Ceballos, Ruben Michael, author.
Title: Bioethanol and natural resources : substrates, chemistry and
engineered systems / Ruben Michael Ceballos.
Description: Boca Raton : CRC Press, [2017] | Includes bibliographical
references and index.
Identifiers: LCCN 2017022730 | ISBN 9781498770415 (hardback : alk. paper) |
ISBN 9781315154299 (ebook)
Subjects: LCSH: Cellulosic ethanol. | Biomass energy. | Biodiesel fuels.
Classification: LCC TP339 .C43 2017 | DDC 668.4/4--dc23
LC record available at https://lccn.loc.gov/2017022730
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Taylor & Francis Group
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© 2018 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group, an Informa business There is nothing wrong with making a little money. People who
work hard should see the benefits of their individual efforts.
No claim to original U.S. Government works
However, when profit is gained off the backs of others or at
Printed on acid-free paper
the expense of our environment, then this is a problem. I was
International Standard Book Number-13: 978-1-4987-7041-5 (Hardback)
once told that things in this world [energy and matter] can
This book contains information obtained from authentic and highly regarded sources. Reasonable efforts neither be created nor destroyed, they can only be transformed
have been made to publish reliable data and information, but the author and publisher cannot assume
responsibility for the validity of all materials or the consequences of their use. The authors and publishers from one state to another. I hear people talk about “creating
have attempted to trace the copyright holders of all material reproduced in this publication and apologize to wealth” in our society and it makes me think. It does not seem
copyright holders if permission to publish in this form has not been obtained. If any copyright material has
not been acknowledged please write and let us know so we may rectify in any future reprint. that wealth can be created from nothing. Generating what
they call “new wealth” comes at the expense of something—
Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmit-
ted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, either at the expense of a person’s sweat and time (and thus
including photocopying, microfilming, and recording, or in any information storage or retrieval system,
without written permission from the publishers. his life) or at the expense of depleting something in nature.
For permission to photocopy or use material electronically from this work, please access www.copyright. It seems that a few people make huge profits at the expense of
com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood
Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and the hard work and lives of others who see only a very small
registration for a variety of users. For organizations that have been granted a photocopy license by the CCC,
fraction of the benefit that their efforts produce. It seems that
a separate system of payment has been arranged.
these same few people also make huge profits off of the land and
Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used
only for identification and explanation without intent to infringe. other natural resources without care for replacing these natural
resources at a rate that matches the rate at which the resource
Library of Congress Cataloging‑in‑Publication Data
is being depleted. This is not “creation of wealth” but the abuse
Names: Ceballos, Ruben Michael, author. of our fellow man and the abuse of our Earth. So, be aware as
Title: Bioethanol and natural resources : substrates, chemistry and
engineered systems / Ruben Michael Ceballos. you move forward and seek profit. Make sure that the profit that
Description: Boca Raton : CRC Press, [2017] | Includes bibliographical
you receive is commensurate with the work that you, yourself,
references and index.
Identifiers: LCCN 2017022730 | ISBN 9781498770415 (hardback : alk. paper) | have done and that you are not profiting at the expense of the
ISBN 9781315154299 (ebook)
lives of your neighbor or to the detriment of our planet.
Subjects: LCSH: Cellulosic ethanol. | Biomass energy. | Biodiesel fuels.
Classification: LCC TP339 .C43 2017 | DDC 668.4/4--dc23
LC record available at https://lccn.loc.gov/2017022730 Go forward and be a responsible, caring, and hard-working
citizen of the world, not just for the sake of yourself, your family,
Visit the Taylor & Francis Web site at and your people but for the benefit of mankind as a whole.
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If you do this, then when you are an old man, I think you will look
back on your life and feel good—that you have done the right thing.
This is more important than any wealth that you may acquire.
This book is dedicated to Catarino Ceballos (Ódami/Tepehuano),
my grandfather, who left school at the age of thirteen to work in the
fields and then later on the Santa Fe railroad, so that he could buy
school uniforms for his younger sisters and who, on retiring from
the railroad, would enroll himself in Palomar College in San Marcos,
California, to finish, as a senior citizen, the education that he had
to leave behind as a young man. Both he and my grandmother,
Isabel, always provided unwavering support for their children
and grandchildren despite being of humble economic means.
As a descendant of both Sephardic and Native American ancestry
and an avid seeker of knowledge, he never lost sight of the need
for compassion for others nor the need to seek balance between
modern development and sustainable use of our natural resources.
Catarino Ceballos (1916–1999)
Isabel Ceballos (1916–2001)
Contents
Preface .................................................................................................................xi
Acknowledgments .........................................................................................xiii
About the author ..............................................................................................xv
Introduction ...................................................................................................xvii
Chapter 1 Molecular substrates of ethanol feedstocks ..........................1
1.1 Starch and sucrose ...................................................................................1
1.1.1 Starch ...........................................................................................1
1.1.2 Sucrose ........................................................................................2
1.2 Cellulosic substrates ................................................................................3
1.2.1 Cellulose ......................................................................................4
1.2.2 Hemicellulose .............................................................................4
1.2.3 Lignin ..........................................................................................7
1.2.4 Pectin ...........................................................................................8
1.2.5 Cross-linking: Hemicellulose ................................................11
1.2.6 Cross-linking: Lignin ..............................................................11
1.2.7 Cross-linking: Pectin ...............................................................13
1.3 Summary: Molecular substrates ..........................................................16
Chapter 2 First-generation biofuel and second-generation
biofuel feedstocks: Biofuel potential and processing .......19
2.1 Corn and sugarcane ..............................................................................19
2.1.1 Corn ...........................................................................................20
2.1.2 Sugarcane ..................................................................................21
2.2 Lignocellulosic biomass ........................................................................22
2.2.1 Corn stover ...............................................................................25
2.2.2 Bagasse ......................................................................................26
2.2.3 Crop straw ................................................................................27
2.2.4 Grasses (perennial energy crops) ..........................................29
2.2.5 Bamboo .....................................................................................30
vii
viii Contents
2.2.6 Woody energy crops and forestry waste .............................31
2.2.7 Municipal waste .......................................................................32
2.2.8 Cellulosic feedstock: A prospectus .......................................34
2.3 Feedstock pretreatments.......................................................................36
2.3.1 Traditional pretreatments for lignocellulosic biomass .......38
2.3.1.1 Physical pretreatments ...........................................38
2.3.1.2 Chemical pretreatments .........................................39
2.3.1.3 Physicochemical pretreatments ............................44
2.3.1.4 Biological pretreatments ........................................47
2.3.2 Advanced pretreatments for lignocellulosic biomass ........48
2.3.2.1 Acid-mediated fractionation .................................49
2.3.2.2 Ionic liquid-based fractionation ............................50
2.4 Summary: Feedstocks and processing ...............................................51
Chapter 3 Natural enzymes used to convert feedstock
to substrate ...........................................................................53
3.1 Mode of action of primary lignocellulolytic enzymes .....................53
3.1.1 Cellulases ..................................................................................54
3.1.1.1 Carbohydrases .........................................................54
3.1.1.2 Oxidoreductive cellulases ......................................57
3.1.1.3 Phosphorylases........................................................59
3.1.2 Hemicellulases .........................................................................60
3.1.2.1 Xylan-degrading enzymes .....................................62
3.1.2.2 Accessory enzymes ................................................64
3.1.3 Ligninolytic enzymes ..............................................................67
3.1.3.1 Peroxidases ..............................................................67
3.1.3.2 Laccases ....................................................................70
3.1.3.3 Accessory enzymes and mediators ......................70
3.1.4 Pectinolytic enzymes (Pectinases) .........................................71
3.1.4.1 Main pectinases ......................................................71
3.1.4.2 Other pectinases .....................................................73
3.2 Natural cellulosomes ............................................................................75
3.2.1 Cellulosome structure .............................................................76
3.2.2 Biological functions of cellulosomes .....................................79
3.2.3 Cellulosome of Clostridium thermocellum ..............................80
3.2.4 Lignocellulolytic system of Trichoderma reesei .....................84
3.3 Summary: Natural enzymes ................................................................88
Acknowledgment .............................................................................................91
Chapter 4 Engineered enzymes and enzyme systems .........................93
4.1 Bioprospecting and metagenomics .....................................................93
4.2 Enzyme engineering .............................................................................94
4.2.1 Rational design ........................................................................95
4.2.2 Directed evolution ...................................................................98
Contents ix
4.2.3 Enzyme engineering and biofuels ......................................103
4.2.4 New technologies for enzyme-mediated
lignocellulose deconstruction ..............................................105
4.2.4.1 Artificial cellulosomes .........................................106
4.2.4.2 Immobilization platforms ....................................108
4.2.4.3 Mobile enzyme platforms ....................................109
4.2.4.4 Future directions ...................................................112
4.3 Summary: Enzyme engineering .......................................................112
Chapter 5 Conclusion ................................................................................117
Literature cited ...............................................................................................121
Index ................................................................................................................197
