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Structural change in wood by brown rot fungi and effect on enzymatic hydrolysis

Paper ID Volume ID Publish Year Pages File Format Full-Text
17391 42665 2011 6 PDF Available
Title
Structural change in wood by brown rot fungi and effect on enzymatic hydrolysis
Abstract

The effects of biological pretreatment on Pinus radiata and Eucalyptus globulus, were evaluated after exposure to two brown rot fungi Gloephylum trabeum and Laetoporeus sulphureus. Changes in chemical composition, structural modification, and susceptibility to enzymatic hydrolysis in the degraded wood were analyzed. After eight weeks of biodegradation, the greatest loss of weight and hemicellulose were 13% and 31%, respectively, for P. radiata with G. trabeum. The content of glucan decreased slightly, being the highest loss of 20% for E. globulus with G. trabeum. Consistent with degradation mechanism of these fungi, lignin was essentially undegraded by both brown rot fungi. Both brown rot fungi cause a sharp reduction in the cellulose degree of polymerization (DP) in the range between 58% and 79%. G. trabeum depolymerized cellulose in both wood faster than L. sulphureus. Also, structural characteristic of crystalline cellulose were measured by using two different techniques – X-ray diffraction (XRD) and infrared spectroscopy (FT-IR). The biological pretreatments showed an effect on cellulose crystallinity structure, a decrease between 6% and 21% was obtained in the crystallinity index (CrI) calculated by IR, no changes were observed in the XRD. Material digestibility was evaluated by enzymatic hydrolysis, the conversion of cellulose to glucose increased with the biotreatment time. The highest enzymatic hydrolysis yields were obtained when saccharification was performed on wood biopretreated with G. trabeum (14% P. radiata and 13% E. globulus). Decreasing in DP and CrI, and hemicellulose removal result in an increase of enzymatic hydrolysis performance. Digestibility was better related to DP than with other properties. G. trabeum can be considered as a potential fungus for biological pretreatment, since it provides an effective process in breaking the wood structure, making it potentially useful in the development of combined pretreatments (biological–chemical). A viable alternative to pretreatment process that can be used is a bio-mimetic system, similar to low-molecular complexes generated by fungi such as G. trabeum combined pretreatments (biological–chemical).

► Ethanol production from softwood is quite complex and requires severe pretreatment. ► Wood digestibility is affected by physical and chemical structural features. ► Fungal pretreatment is liable for breaking down the cellulose crystalline structure. ► Brown rot fungi disrupt lignin–cellulose complexes and remove the hemicellulose. ► A viable alternative is using a biomimetic system combined with chemical pretreatment.

Keywords
Brown rot fungi; Enzymatic hydrolysis; Polymerization degree; Crystallinity
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Structural change in wood by brown rot fungi and effect on enzymatic hydrolysis
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 49, Issue 5, 10 October 2011, Pages 472–477
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us