Physicochemical properties of pretreated poplar feedstocks during simultaneous saccharification and fermentation

Meunier-Goddik, Lisbeth; Bothwell, Michelle Kay; Sangseethong, Kunruedee; Piyachomkwan, Kuakoon; Chung, Yun‐Chin; Thammasouk, Khamphet; Tanjo, Djuhartini; Penner, Michael H.

doi:10.1016/s0141-0229(99)00003-4

Cited by 21 publications

(9 citation statements)

References 36 publications

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“…Reported CrI values for pretreated materials are generally in the range of 0.4 -0.7 (Chang and Holtzapple, 2000;Gharpuray et al, 1983;Koullas et al, 1992;Sinitsyn et al, 1989Sinitsyn et al, , 1991. Pretreatment by either dilute-acid or steam explosion under conditions that are quite effective in enhancing hydrolysis has been found to increase the composite CrI of lignocellulose (Deschamps et al, 1996;Kim et al, 2003;Knappert et al, 1980;Meunier-Goddik et al, 1999). Consistent with this, a negative correlation between hydrolysis rate and CrI has been shown in experiments that involved chemical pretreatments followed by ball milling (Chang and Holtzapple, 2000;Gharpuray et al, 1983;Knappert et al, 1980;Koullas et al, 1992;Sinitsyn et al, 1989Sinitsyn et al, , 1991, and also experiments that examined various pretreatment conditions (Chang and Holtzapple, 2000).…”

Section: Characteristics Of Pretreated Lignocellulosementioning

confidence: 61%

Toward an aggregated understanding of enzymatic hydrolysis of cellulose: Noncomplexed cellulase systems

Zhang

Lynd

2004

Biotech & Bioengineering

1,646

1,284

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Information pertaining to enzymatic hydrolysis of cellulose by noncomplexed cellulase enzyme systems is reviewed with a particular emphasis on development of aggregated understanding incorporating substrate features in addition to concentration and multiple cellulase components. Topics considered include properties of cellulose, adsorption, cellulose hydrolysis, and quantitative models. A classification scheme is proposed for quantitative models for enzymatic hydrolysis of cellulose based on the number of solubilizing activities and substrate state variables included. We suggest that it is timely to revisit and reinvigorate functional modeling of cellulose hydrolysis, and that this would be highly beneficial if not necessary in order to bring to bear the large volume of information available on cellulase components on the primary applications that motivate interest in the subject. B

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Section: Characteristics Of Pretreated Lignocellulosementioning

confidence: 61%

Toward an aggregated understanding of enzymatic hydrolysis of cellulose: Noncomplexed cellulase systems

Zhang

Lynd

2004

Biotech & Bioengineering

1,646

1,284

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“…More recently, advances in cloning technologies and purification procedures have allowed the use of purified enzymes to distinguish between enzyme and substrate effects in the experiments (Eriksson et al, 2002;Palonen et al, 2004). Additionally, determining bound enzyme fractions in the reactions has become more direct and quantitative, using known extinction coefficients of the well-characterized and carefully purified enzyme components instead of indirect activity based (Meunier-Goddik et al, 1999) or colorimetric methods (Ooshima et al, 1991). However, determining the bound enzyme fraction on biomass is further complicated by the absorbance contributions of various soluble components in biomass (Ucar and Fengel, 1988).…”

Section: Discussionmentioning

confidence: 99%

Cellulase digestibility of pretreated biomass is limited by cellulose accessibility

Jeoh¹,

Ishizawa²,

Davis³

et al. 2007

Biotech & Bioengineering

460

321

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Attempts to correlate the physical and chemical properties of biomass to its susceptibility to enzyme digestion are often inconclusive or contradictory depending on variables such as the type of substrate, the pretreatment conditions and measurement techniques. In this study, we present a direct method for measuring the key factors governing cellulose digestibility in a biomass sample by directly probing cellulase binding and activity using a purified cellobiohydrolase (Cel7A) from Trichoderma reesei. Fluorescence-labeled T. reesei Cel7A was used to assay pretreated corn stover samples and pure cellulosic substrates to identify barriers to accessibility by this important component of cellulase preparations. The results showed cellulose conversion improved when T. reesei Cel7A bound in higher concentrations, indicating that the enzyme had greater access to the substrate. Factors such as the pretreatment severity, drying after pretreatment, and cellulose crystallinity were found to directly impact enzyme accessibility. This study provides direct evidence to support the notion that the best pretreatment schemes for rendering biomass more digestible to cellobiohydrolase enzymes are those that improve access to the cellulose in biomass cell walls, as well as those able to reduce the crystallinity of cell wall cellulose.

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“…O índice de cristalinidade (Ic) da celulose foi calculado através da equação: Ic = 1 -I 1 / I 2 [7,30,31] , onde I 1 = intensidade do mínimo de difração, relacionada à parte amorfa (2θ = 18,8°) e I 2 = intensidade do máximo de difração, relacionada à parte cristalina (2θ = 22,4°). Este método foi desenvolvido por Segal e colaboradores [30] e tem sido largamente utilizado para o estudo de fibras naturais [7,9,10,[31][32][33][34][35] .…”

Section: Methodsunclassified

Caracterização química e estrutural de fibra de sisal da variedade Agave sisalana

et al. 2009

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e beneficiamento da fibra e termina com a industrialização e confecção de artesanato [1,2,[4][5][6] .A planta do sisal é originária da península de Yucatã, no México, tendo recebido este nome de uma erva nativa chamada zizal-xiu [4] . Em 1834, as primeiras mudas foram levadas para o sul da Flórida (EUA) e a partir de 1892 começaram a ser cultivadas na África. No Brasil, as primeiras mudas de Agave sisalana Perrine foram introduzidas na Bahia em 1903, sendo esta a única espécie do gênero Agave cultivada comercialmente no país [5][6][7] . As fibras são extraídas das folhas, que possuem de 8 a 10 cm de largura e de 150 a 200 cm de comprimento. Da folha se obtém de 3 a 5% do seu peso em fibra. Os 95 a 97% restantes constituem os chamados resíduos do beneficiamento, que são utilizados como adubo orgânico, ração animal e pela indús-tria farmacêutica. As fibras são constituídas de fibrilas ou IntroduçãoO sisal é a principal fibra dura produzida no mundo, correspondendo a aproximadamente 70% da produção comercial de todas as fibras desse tipo. No Brasil, o cultivo do sisal se concentra na região Nordeste, sendo os estados da Bahia, Paraíba e Rio Grande do Norte os principais produtores, com 93,5, 3,5 e 3,0%, respectivamente, da produção nacional [1][2][3] . A agaveicultura se concentra em áreas de pequenos produtores, com predomínio do trabalho familiar. O sisal, além de constituir fonte de renda e emprego para um grande contingente de trabalhadores, é um importante agente de fixação do homem à região semi-árida nordestina, sendo, em algumas dessas regiões, a única alternativa de cultivo com resultados econômicos satisfatórios. A fibra do sisal, beneficiada ou industrializada, representa cerca de 80 milhões de dólares em divisas para o Brasil, além de gerar mais de meio milhão de empregos diretos e indiretos por Resumo: Nos últimos anos, o interesse pelo uso de fibras naturais em materiais compósitos poliméricos tem aumentado significativamente. Neste trabalho foram investigadas as propriedades, químicas, físicas, térmicas e estruturais da fibra de sisal brasileira da variedade Agave sisalana. Nosso objetivo foi avaliar a qualidade e o desempenho desta fibra para aplicações industriais. Foram realizados ensaios de resistência à tração, análise da composição química, difração de raios X, e estudos por microscopia eletrônica de varredura (MEV) ao longo do comprimento da fibra. A fibra de sisal brasileira apresentou propriedades mecânicas e térmicas dentro da faixa relatada na literatura, mostrando-se adequada para ser utilizada em materiais compósitos poliméricos. Palavras-chave: Fibras naturais, compósitos, composição química, caracterização. Chemical and Structural Characterization of Sisal Fibers from Agave sisalana VarietyAbstract: In recent years, the interest in the use of natural fibers in polymeric composite materials has increased significantly. In this work were investigated the structural, thermal, chemical, and physical properties of Brazilian sisal fiber from Agave sisalana variety. Our aim was to evaluate th...

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Physicochemical properties of pretreated poplar feedstocks during simultaneous saccharification and fermentation

Cited by 21 publications

References 36 publications

Toward an aggregated understanding of enzymatic hydrolysis of cellulose: Noncomplexed cellulase systems

Toward an aggregated understanding of enzymatic hydrolysis of cellulose: Noncomplexed cellulase systems

Cellulase digestibility of pretreated biomass is limited by cellulose accessibility

Caracterização química e estrutural de fibra de sisal da variedade Agave sisalana

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