Lignocellulose biodegradation: Fundamentals and applications

Malherbe, Sulette; Cloete, T.E.

doi:10.1023/a:1020858910646

Cited by 405 publications

(204 citation statements)

References 63 publications

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“…Fungi breakdown lignin anaerobically through the use of a family of extracellular enzymes collectively termed ''lignases'' [31]. Two families of lignolytic enzymes are widely considered to play a key role in the enzymatic degradation: phenol oxidase (laccase) and peroxidases (lignin peroxidase, LiP and manganese peroxidase, MnP) [32,33]. Other enzymes whose roles have not been fully elucidated include glyoxal oxidase, glucose oxidase, oxido-reductase and methanol oxidase [34].…”

Section: Biological Pretreatmentmentioning

confidence: 99%

“…The industrial scale implementation of lignocellulosebased biotechnologies utilizing the ability of an appropriate microorganism to selectively degrade lignin was realized when Malherbe and Cloete [33] reiterated that the primary objective of lignocellulose treatment by the various industries is to access the potential of the cellulose encrusted by lignin within the lignocellulose matrix. Studies have shown that Lentinus edodes [41], Pleurotes spp.…”

Section: Biological Pretreatmentmentioning

confidence: 99%

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Biological Pretreatment of Lignocellulosic Substrates for Enhanced Delignification and Enzymatic Digestibility

2011

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Sheer enormity of lignocellulosics makes them potential feedstock for biofuel production but, their conversion into fermentable sugars is a major hurdle. They have to be pretreated physically, chemically, or biologically to be used by fermenting organisms for production of ethanol. Each lignocellulosic substrate is a complex mix of cellulose, hemicellulose and lignin, bound in a matrix. While cellulose and hemicellulose yield fermentable sugars, lignin is the most recalcitrant polymer, consisting of phenyl-propanoid units. Many microorganisms in nature are able to attack and degrade lignin, thus making access to cellulose easy. Such organisms are abundantly found in forest leaf litter/composts and especially include the wood rotting fungi, actinomycetes and bacteria. These microorganisms possess enzyme systems to attack, depolymerize and degrade the polymers in lignocellulosic substrates. Current pretreatment research is targeted towards developing processes which are mild, economical and environment friendly facilitating subsequent saccharification of cellulose and its fermentation to ethanol. Besides being the critical step, pretreatment is also cost intensive. Biological treatments with white rot fungi and Streptomyces have been studied for delignification of pulp, increasing digestibility of lignocellulosics for animal feed and for bioremediation of paper mill effluents. Such lignocellulolytic organisms can prove extremely useful in production of bioethanol when used for removal of lignin from lignocellulosic substrate and also for cellulase production. Our studies on treatment of hardwood and softwood residues with Streptomyces griseus isolated from leaf litter showed that it enhanced the mild alkaline solubilisation of lignins and also produced high levels of the cellulase complex when growing on wood substrates. Lignin loss (Klason lignin) observed was 10.5 and 23.5% in case of soft wood and hard wood, respectively. Thus, biological pretreatment process for lignocellulosic substrate using lignolytic organisms such as actinomycetes and white rot fungi can be developed for facilitating efficient enzymatic digestibility of cellulose.

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Section: Biological Pretreatmentmentioning

confidence: 99%

Section: Biological Pretreatmentmentioning

confidence: 99%

Biological Pretreatment of Lignocellulosic Substrates for Enhanced Delignification and Enzymatic Digestibility

2011

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“…Their composition makes them of veritable biotechnological value (12). In the tropics and around the world, a lot of plant materials are generated all the year round through forestry and agro-industrial practices and thus constitute pollution problems.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of a β-1,4-D endoglucanase from Trichoderma virens wholly applied in a palm-fruit husk-based diet for poultry layers

Odeniyi

Onilude

Ayodele

2012

Braz. J. Microbiol.

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The characteristics of an endoglucanase produced by a Trichoderma virens strain T9 newly isolated from a palm-fruit husk dump site, its physiological characteristics and enzyme production were studied. Whole cells of the depolymerizing-enzyme producing T. virens were applied to palm-fruit husk and bird performance characteristics when employed as poultry diet additive were considered. Endoglucanase activity in submerged fermentation was 1.6 nkat. Optimum activity was recorded at pH 6.0 and 55 o C. The enzyme retained 50% residual glucanase activity at 70 o C for 10 minutes. 1.0% Tween-80 and SDS yielded endoglucanase activity 2.15 times higher than the control. Activity was boosted by 20mM Ca 2+ (115.0%); 10mM K + (106.5%); and was totally inhibited by 1mM Hg 2+ . The addition of T. virens-fermented palm-fruit husk with other layer feed components on the bird characteristics showed that change in bird weight between the control and test birds were not significantly different (p>0.05) but differed in terms of daily feed ingested (p<0.05). The feed to weight-gain ratio was best with the unmodified palm-fruit husk based diet (8.59). There was no significant difference in the egg weights from modified palm-fruit husk based diet and control (p>0.05). The shell thickness (0.64mm) and yolk content (23.61%) were highest in the microbially-modified husk diet.The alternative to maize based diets proffered by the application of T. virens-modified palm-fruit husk in poultry nutrition in terms of bird weight and feed to weight-gain ratio affords the poultry farmer an economic advantage and allows for a greater utilization of the maize in human diets.

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“…Besides, lignin is associated with cellulose/hemicellulose to form a cross-linked threedimensional structure which can inhibit microbial access to biodegradable fractions (Malherbe and Cloete, 2002). However, the cellulose present in cardboard/paper is less resistant than cellulose of wood due to changes induced in the paper manufacturing (Eklind and Kirchmann, 2000a).…”

mentioning

confidence: 99%

“…However, the cellulose present in cardboard/paper is less resistant than cellulose of wood due to changes induced in the paper manufacturing (Eklind and Kirchmann, 2000a). As for hemicellulose, although the types of enzymes involved in its degradation are similar to cellulose, more enzymes are required for its complete degradation due to its greater complexity in comparison with the linear polymer cellulose (Malherbe andCloete, 2002, Sánchez, 2009). Therefore cellulose can be expected to show higher decomposition rate, followed by hemicellulose.…”

mentioning

confidence: 99%

Life Cycle Assessment (LCA) of Light-Weight Eco-composites

Guo¹

2012

Springer Theses

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LCA of Light-weight Eco-composites Statement of originality 2 Statement of originalityI hereby declare that this submission is my own work and to the best of my knowledge it contains no materials previously published or written by another person.Contributions made to the research of this thesis by others, with whom I have worked with are explicitly acknowledged. I also declare that the intellectual content of this thesis is the product of my own work, except to the extent that assistance from others with data collection and modification of process-oriented model DNDC is acknowledged. Miao GuoSep 2010 LCA of Light-weight Eco-compositesAbstract 3 AbstractThe environmental profiles of novel wheat based foam materials were investigated in this thesis using Life Cycle Assessment (LCA) methods. The LCAs were developed using primary data collected from industrial sources combined with new laboratory experiments supplemented with secondary data from publicly available sources.Laboratory research was conducted to obtain important missing data on WBFs for the LCA modelling, including physico-chemical parameters, biodegradability and energy recovery under anaerobic digestion conditions.Contribution analysis suggested that the emissions evolved from the wheat agroecosystem and PVOH production, together with the energy and infrastructure involved in WBF production were the major contributors to the environmental burdens of the WBF life cycle in most impact categories. The atmospheric emissions resulting from WBF degradation at the end-of-life also emerged as another important contributor to environmental impact. Amongst the diverse ‗end-of-life' scenarios examined, AD and home composting were suggested to be the optimum choices for WBF waste treatment. This research discusses two N 2 O modelling approaches and presents a method to expand the system boundary by integrating the process-oriented model DNDC for field emissions into the LCA. Sensitivity analysis suggests that the environmental profiles of agricultural products are influenced substantially by the system boundary definition. LCA of Light-weight Eco-compositesAbstract 4 Furthermore, it suggests that the ‗general rule' in LCA practice by applying an empirical model or a default emission factor (EF) could deliver unreliable LCA findings.This study also evaluated the sensitivity of the LCA results to methodology and data variations and quantified the uncertainties in the LCA outcomes arising from uncertainty in the inventory and data variability. This has led to an increase in confidence in the LCA findings. At the same time it indicates the areas where improvements in data or methods are needed in order for robust conclusions to be drawn and unbiased information to be delivered e.g. the methodological rigidity of characterization models, the IPCC Tier 1 EF uncertainty range. LCA of Light-weight Eco-compositesAcknowledgements 5

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Lignocellulose biodegradation: Fundamentals and applications

Cited by 405 publications

References 63 publications

Biological Pretreatment of Lignocellulosic Substrates for Enhanced Delignification and Enzymatic Digestibility

Biological Pretreatment of Lignocellulosic Substrates for Enhanced Delignification and Enzymatic Digestibility

Characteristics of a β-1,4-D endoglucanase from Trichoderma virens wholly applied in a palm-fruit husk-based diet for poultry layers

Life Cycle Assessment (LCA) of Light-Weight Eco-composites

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Lignocellulose biodegradation: Fundamentals and applications

Cited by 405 publications

References 63 publications

Biological Pretreatment of Lignocellulosic Substrates for Enhanced Delignification and Enzymatic Digestibility

Biological Pretreatment of Lignocellulosic Substrates for Enhanced Delignification and Enzymatic Digestibility

Characteristics of a &#946;-1,4-D endoglucanase from Trichoderma virens wholly applied in a palm-fruit husk-based diet for poultry layers

Life Cycle Assessment (LCA) of Light-Weight Eco-composites

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Product

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Characteristics of a β-1,4-D endoglucanase from Trichoderma virens wholly applied in a palm-fruit husk-based diet for poultry layers