138 research outputs found
Cellulose morphology and enzymatic reactivity: a modified solute exclusion technique
An expeditious and accurate simplification of Stone and Scallan's solute exclusion technique was developed, thereby avoiding several sources of experimental error coupled with the determination of cellulose pore volume. Using this method, it is shown that cellulolytic enzymes do not enter into the micropores of five studied celluloses. These results suggestes that hydrolysis occurs initially at the external surface of the fibers. This surface area was calculated with the help of adsorption isotherms of bovine serum albumin. The obtained values for the different samples agree with the microscopically observed cellulose morphology. The correlation obtained by several authors relating cellulose porosity and its digestibility is explained as a consequence of the lower crystallinity and easier fragmentation of the more porous celluloses during hydrolysis
The effect of agitation speed, enzyme loading and substrate concentration on enzymatic hydrolysis of cellulose from brewer’s spent grain
Brewer’s spent grain components (cellulose,
hemicellulose and lignin) were fractionated in a
two-step chemical pretreatment process using dilute
sulfuric acid and sodium hydroxide solutions. The
cellulose pulp produced was hydrolyzed with a
cellulolytic complex, Celluclast 1.5 L, at 45 ºC to
convert the cellulose into glucose. Several conditions
were examined: agitation speed (100, 150 and
200 rpm), enzyme loading (5, 25 and 45 FPU/g
substrate), and substrate concentration (2, 5 and 8%
w/v), according to a 2 3 full factorial design aiming to
maximize the glucose yield. The obtained results
were interpreted by analysis of variance and response
surface methodology. The optimal conditions for
enzymatic hydrolysis of brewer’s spent grain were
identified as 100 rpm, 45 FPU/g and 2% w/v substrate.
Under these conditions, a glucose yield of
93.1% and a cellulose conversion (into glucose and
cellobiose) of 99.4% was achieved. The easiness of
glucose release from BSG makes this substrate a raw material with great potential to be used in bioconversion
processes.Coordenação de Aperfeiçoamento de Pessoal de NÃvel
Superior (CAPES)Fundação de Amparo
à Pesquisa do Estado de São Paulo), Brazil. Novozymes ( FAPESP )Conselho Nacional de Desenvolvimento
CientÃfico e Tecnológico (CNPq
Rhabdomyoblastic Differentiation in Head and Neck Malignancies Other Than Rhabdomyosarcoma
Rhabdomyosarcoma is a relatively common soft tissue sarcoma that frequently affects children and adolescents and may involve the head and neck. Rhabdomyosarcoma is defined by skeletal muscle differentiation which can be suggested by routine histology and confirmed by immunohistochemistry for the skeletal muscle-specific markers myogenin or myoD1. At the same time, it must be remembered that when it comes to head and neck malignancies, skeletal muscle differentiation is not limited to rhabdomyosarcoma. A lack of awareness of this phenomenon could lead to misdiagnosis and, subsequently, inappropriate therapeutic interventions. This review focuses on malignant neoplasms of the head and neck other than rhabdomyosarcoma that may exhibit rhabdomyoblastic differentiation, with an emphasis on strategies to resolve the diagnostic dilemmas these tumors may present. Axiomatically, no primary central nervous system tumors will be discussed.info:eu-repo/semantics/publishedVersio
GPIB interface for testing and controlling laboratory projects
Typescript (photocopy).Digitized by Kansas Correctional IndustriesDepartment: Electrical and Computer Engineering
The effect of pretreatments on the rate of enzymatic hydrolysis of wheat straw and its structural features
Typescript (photocopy).Digitized by Kansas Correctional Industrie
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