Cellulases have traditionally been studied in the context of cellulose degradation to fermentable sugars, like glucose, for ethanol production. Cellulose recalcitrance to enzymatic degradation has long been considered as a critical technological barrier for commercialization of cellulosic biofuels. Recent research has led to the development of a cost-effective ammonia-based pretreatment method that allows modification of the crystalline allomorphic structure of cellulose from native cellulose-I to cellulose-III.* Chundawat and co-workers have already demonstrated that cellulose-III is up to five folds more digestible than native cellulose I by Trichoderma reesei derived fungal cellulase enzymes. † This improvement in fungal cellulase cocktail activity was shown to be largely arising due to enhanced endolytic-exolytic cellulase enzyme synergy on pretreated cellulose-III. Here, we explore the activity of cellulases secreted by a highly cellulolytic actinomycete called Thermobifida fusca. To the best of our knowledge, the work here signifies the first reported attempt to characterize the activity of T. fusca expressed cellulase cocktails and purified bacterial cellulases on pretreated cellulose-III. The four specific objectives that were completed to accomplish this goal were; (i) develop and optimize a cell culturing method for T. fusca growth to maximize recovered cellulase activity, (ii) characterize the activity of isolated crude T. fusca cellulase cocktails on native and ammonia-pretreated cellulose allomorphs, (iii) develop a protein purification protocol to isolate and purify T. fusca exocellulase (Cel6B) to electrophoretic homogeneity, and (iv) run enzyme synergism ‘re-start’ hydrolysis assays on isolated exocellulase Cel6B in concert with another bacterial endocellulase (CelE) to confirm if bacterial cellulases also show improved endo- exosynergistic activity on cellulose-III. Our results led further credence to our initial hypothesis that free cellulolytic enzyme cocktails, derived from either fungal or bacterial sources, show enhanced endo-exo synergy on pretreated cellulose-III. We also discuss future research directions and the relevance of the research to our understanding about how cellulases deconstruct various crystalline cellulose allomorphs in general.
Subject (authority = RUETD)
Topic
Chemical and Biochemical Engineering
Subject (authority = ETD-LCSH)
Topic
Cellulase
RelatedItem (type = host)
TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
Identifier (type = RULIB)
ETD
Identifier
ETD_9203
PhysicalDescription
Form (authority = gmd)
electronic resource
InternetMediaType
application/pdf
InternetMediaType
text/xml
Extent
1 online resource (69 pages) : illustrations
Note (type = degree)
M.S.
Note (type = bibliography)
Includes bibliographical references
Note (type = statement of responsibility)
by Yuxin Liu
RelatedItem (type = host)
TitleInfo
Title
School of Graduate Studies Electronic Theses and Dissertations
Identifier (type = local)
rucore10001600001
Location
PhysicalLocation (authority = marcorg); (displayLabel = Rutgers, The State University of New Jersey)
I hereby grant to the Rutgers University Libraries and to my school the non-exclusive right to archive, reproduce and distribute my thesis or dissertation, in whole or in part, and/or my abstract, in whole or in part, in and from an electronic format, subject to the release date subsequently stipulated in this submittal form and approved by my school. I represent and stipulate that the thesis or dissertation and its abstract are my original work, that they do not infringe or violate any rights of others, and that I make these grants as the sole owner of the rights to my thesis or dissertation and its abstract. I represent that I have obtained written permissions, when necessary, from the owner(s) of each third party copyrighted matter to be included in my thesis or dissertation and will supply copies of such upon request by my school. I acknowledge that RU ETD and my school will not distribute my thesis or dissertation or its abstract if, in their reasonable judgment, they believe all such rights have not been secured. I acknowledge that I retain ownership rights to the copyright of my work. I also retain the right to use all or part of this thesis or dissertation in future works, such as articles or books.