Enzymatic depolymerisation of cellulose

Pala, Helena; Мота, М.; Gama, Miguel

doi:10.1016/j.carbpol.2006.07.015

Cited by 49 publications

(24 citation statements)

References 19 publications

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“…18 Cellulases are classified as Endoglucanase (EG), Exoglucanase (cellobiohydrolase, CBH) or Cellobiase (b-glucosidase, BG) based on the form of cellulose they operate on (crystalline, amorphous, oligosaccharide, or cellobiose). 19 Their synergic function usually leads to a complete degradation of cellulose. 20 The activity of these cellulases is dependent on pH and temperature.…”

Section: Introductionmentioning

confidence: 99%

Integration of cellulases into bacterial cellulose: Toward bioabsorbable cellulose composites

Catchmark

2011

J Biomed Mater Res

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Cellulose biodegradation resulting from enzymolysis generally occurs in nature rather than in the human body because of the absence of cellulose degrading enzymes. In order to achieve in-vivo degradation in human body for in-vivo tissue regeneration applications, we developed a bioaborbable bacterial cellulose (BBC) material, which integrates one or more cellulose degrading enzymes (cellulases), and demonstrated its degradability in vitro using buffers with pH values relevant to wound environments. We introduced a double lyophilizing process to retain the microstructure of the bacterial cellulose as well as the activity of embedded enzymes allowing for long-term storage of the material, which only requires hydration before use. Enzymes and their combinations have been examined to optimize the in-vitro degradation of the BBC material. In-vitro studies revealed that acidic cellulases from Trichoderma viride showed reasonable activity for pH values ranging from 4.5 to 6.0. A commercial cellulase (cellulase-5000) did not show good activity at pH 7.4, but its degrading ability increased when used in conjunction with a β-glucosidase from Bacillus subtilis or a β-glucosidase from Trichoderma sp. Given the harmless glucose product of the enzymatic degradation of cellulose, the BBC material may be ideal for many wound care and tissue engineering applications for the bioabsorbable purpose.

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Section: Introductionmentioning

confidence: 99%

Integration of cellulases into bacterial cellulose: Toward bioabsorbable cellulose composites

Catchmark

2011

J Biomed Mater Res

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“…To track the hydrolysis process, soluble sugar release [187] and molecular weight of residues [188] have often been measured by using HPLC or DNS method. Compared to sugars analysis, the characterization of residual substrate can provide a more direct understand of enzyme-cellulose interactions.…”

Section: The Mechanisms Of Cellulose Hydrolysismentioning

confidence: 99%

Bioconversion of Lignocellulose into Bioethanol: Process Intensification and Mechanism Research

Huang

et al. 2011

Bioenerg. Res.

123

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Biofuels produced from lignocellulosic biomass can significantly reduce the energy dependency on fossil fuels and the resulting effects on environment. In this respect, cellulosic ethanol as an alternative fuel has the potential to become a viable energy source in the near future. Over the past few decades, tremendous effort has been undertaken to make cellulosic ethanol cost competitive with conventional fossil fuels. The pretreatment step is always necessary to deconstruct the recalcitrant structures and to make cellulose more accessible to enzymes. A large number of pretreatment technologies involving physical, chemical, biological, and combined approaches have been developed and tested at the pilot scale. Furthermore, various strategies and methods, including multi-enzyme complex, non-catalytic additives, enzyme recycling, high solids operation, design of novel bioreactors, and strain improvement have also been implemented to improve the efficiency of subsequent enzymatic hydrolysis and fermentation. These technologies provide significant opportunities for lower total cost, thus making large-scale production of cellulosic ethanol possible. Meanwhile, many researchers have focused on the key factors that limit cellulose hydrolysis, and analyzing the reaction mechanisms of cellulase. This review describes the most recent advances on process intensification and mechanism research of pretreatment, enzymatic hydrolysis, and fermentation during the production of cellulosic ethanol.

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“…Its well-ordered hydrogen bonding network makes it notoriously resistant to hydrolysis [9]. Up to now, cellulose hydrolysis mainly involves the use of acids [10,11], enzymes [12] and hot-compressed water [8,13]. Mostly, polyols obtained via these methods, in combination with hydrogenation reaction, are sorbitol and mannitol.…”

Section: Introductionmentioning

confidence: 98%

Cellulose conversion to polyols on supported Ru catalysts in aqueous basic solution

2010

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It is of great significance and challenge to achieve direct conversion of cellulose to specific polyols, e.g., ethylene glycol and propylene glycol. For such selective conversion, a novel one-pot approach was studied by combination of alkaline hydrolysis and hydrogenation on supported Ru catalysts. A wide range of bases including solid bases, e.g., Ca(OH) 2 and La 2 O 3 , and phosphate buffers were examined in the cellulose reaction in water, and the cellulose conversions and polyol products depended largely on the basicity or pH values in the aqueous solutions. Ethylene glycol, 1,2-propanediol, and especially 1,2,5-pentanetriol were obtained with selectivities of 15%, 14% and 22%, respectively, at 38% cellulose conversion at pH 8 in phosphate buffer solution. These preliminary results provide potentials for efficient conversion of cellulose to targeted polyols by using the advantages of bases. cellulose, polyols, Ru catalysts, solid bases, aqueous basic solutions

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Enzymatic depolymerisation of cellulose

Cited by 49 publications

References 19 publications

Integration of cellulases into bacterial cellulose: Toward bioabsorbable cellulose composites

Integration of cellulases into bacterial cellulose: Toward bioabsorbable cellulose composites

Bioconversion of Lignocellulose into Bioethanol: Process Intensification and Mechanism Research

Cellulose conversion to polyols on supported Ru catalysts in aqueous basic solution

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