Cargando…
Use of bacteria for improving the lignocellulose biorefinery process: importance of pre-erosion
BACKGROUND: Biological pretreatment is an important alternative strategy for biorefining lignocellulose and has attracted increasing attention in recent years. However, current designs for this pretreatment mainly focus on using various white rot fungi, overlooking the bacteria. To the best of our k...
Autores principales: | , , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2018
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5964970/ https://www.ncbi.nlm.nih.gov/pubmed/29796087 http://dx.doi.org/10.1186/s13068-018-1146-4 |
_version_ | 1783325275041300480 |
---|---|
author | Zhuo, Shengnan Yan, Xu Liu, Dan Si, Mengying Zhang, Kejing Liu, Mingren Peng, Bing Shi, Yan |
author_facet | Zhuo, Shengnan Yan, Xu Liu, Dan Si, Mengying Zhang, Kejing Liu, Mingren Peng, Bing Shi, Yan |
author_sort | Zhuo, Shengnan |
collection | PubMed |
description | BACKGROUND: Biological pretreatment is an important alternative strategy for biorefining lignocellulose and has attracted increasing attention in recent years. However, current designs for this pretreatment mainly focus on using various white rot fungi, overlooking the bacteria. To the best of our knowledge, for the first time, we evaluated the potential contribution of bacteria to lignocellulose pretreatment, with and without a physicochemical process, based on the bacterial strain Pandoraea sp. B-6 (hereafter B-6) that was isolated from erosive bamboo slips. Moreover, the mechanism of the improvement of reducing sugar yield by bacteria was elucidated via analyses of the physicochemical changes of corn stover (CS) before and after pretreatment. RESULTS: The digestibility of CS pretreated with B-6 was equivalent to that of untreated CS. The recalcitrant CS surface provided fewer mediators for contact with the extracellular enzymes of B-6. A pre-erosion strategy using a tetrahydrofuran–water co-solvent system was shown to destroy the recalcitrant CS surface. The optimal condition for pre-erosion showed a 6.5-fold increase in enzymatic digestibility compared with untreated CS. The pre-erosion of CS can expose more phenolic compounds that were chelated to oxidized Mn(3+) and also provided mediators for combination with laccase, which was attributable to B-6 pretreatment. B-6 pretreatment following pre-erosion exhibited a sugar yield that was 91.2 mg/g greater than that of pre-erosion alone and 7.5-fold higher than that of untreated CS. This pre-erosion application was able to destroy the recalcitrant CS surface, thus leading to a rough and porous architecture that better facilitated the diffusion and transport of lignin derivatives. This enhanced the ability of laccase and manganese peroxidase secreted by B-6 to improve the efficiency of this biological pretreatment. CONCLUSION: Bacteria were not found useful alone as a biological pretreatment, but they significantly improved enzymatic digestion after lignocellulose breakdown via other physicochemical methods. Nonetheless, phenyl or phenoxy radicals were used by laccase and manganese peroxidase in B-6 for lignin attack or lignin depolymerization. These particular mediators released from the recalcitrance network of lignocellulose openings are important for the efficacy of this bacterial pretreatment. Our findings thus offer a novel perspective on the effective design of biological pretreatment methods for lignocellulose. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13068-018-1146-4) contains supplementary material, which is available to authorized users. |
format | Online Article Text |
id | pubmed-5964970 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-59649702018-05-24 Use of bacteria for improving the lignocellulose biorefinery process: importance of pre-erosion Zhuo, Shengnan Yan, Xu Liu, Dan Si, Mengying Zhang, Kejing Liu, Mingren Peng, Bing Shi, Yan Biotechnol Biofuels Research BACKGROUND: Biological pretreatment is an important alternative strategy for biorefining lignocellulose and has attracted increasing attention in recent years. However, current designs for this pretreatment mainly focus on using various white rot fungi, overlooking the bacteria. To the best of our knowledge, for the first time, we evaluated the potential contribution of bacteria to lignocellulose pretreatment, with and without a physicochemical process, based on the bacterial strain Pandoraea sp. B-6 (hereafter B-6) that was isolated from erosive bamboo slips. Moreover, the mechanism of the improvement of reducing sugar yield by bacteria was elucidated via analyses of the physicochemical changes of corn stover (CS) before and after pretreatment. RESULTS: The digestibility of CS pretreated with B-6 was equivalent to that of untreated CS. The recalcitrant CS surface provided fewer mediators for contact with the extracellular enzymes of B-6. A pre-erosion strategy using a tetrahydrofuran–water co-solvent system was shown to destroy the recalcitrant CS surface. The optimal condition for pre-erosion showed a 6.5-fold increase in enzymatic digestibility compared with untreated CS. The pre-erosion of CS can expose more phenolic compounds that were chelated to oxidized Mn(3+) and also provided mediators for combination with laccase, which was attributable to B-6 pretreatment. B-6 pretreatment following pre-erosion exhibited a sugar yield that was 91.2 mg/g greater than that of pre-erosion alone and 7.5-fold higher than that of untreated CS. This pre-erosion application was able to destroy the recalcitrant CS surface, thus leading to a rough and porous architecture that better facilitated the diffusion and transport of lignin derivatives. This enhanced the ability of laccase and manganese peroxidase secreted by B-6 to improve the efficiency of this biological pretreatment. CONCLUSION: Bacteria were not found useful alone as a biological pretreatment, but they significantly improved enzymatic digestion after lignocellulose breakdown via other physicochemical methods. Nonetheless, phenyl or phenoxy radicals were used by laccase and manganese peroxidase in B-6 for lignin attack or lignin depolymerization. These particular mediators released from the recalcitrance network of lignocellulose openings are important for the efficacy of this bacterial pretreatment. Our findings thus offer a novel perspective on the effective design of biological pretreatment methods for lignocellulose. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13068-018-1146-4) contains supplementary material, which is available to authorized users. BioMed Central 2018-05-23 /pmc/articles/PMC5964970/ /pubmed/29796087 http://dx.doi.org/10.1186/s13068-018-1146-4 Text en © The Author(s) 2018 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Zhuo, Shengnan Yan, Xu Liu, Dan Si, Mengying Zhang, Kejing Liu, Mingren Peng, Bing Shi, Yan Use of bacteria for improving the lignocellulose biorefinery process: importance of pre-erosion |
title | Use of bacteria for improving the lignocellulose biorefinery process: importance of pre-erosion |
title_full | Use of bacteria for improving the lignocellulose biorefinery process: importance of pre-erosion |
title_fullStr | Use of bacteria for improving the lignocellulose biorefinery process: importance of pre-erosion |
title_full_unstemmed | Use of bacteria for improving the lignocellulose biorefinery process: importance of pre-erosion |
title_short | Use of bacteria for improving the lignocellulose biorefinery process: importance of pre-erosion |
title_sort | use of bacteria for improving the lignocellulose biorefinery process: importance of pre-erosion |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5964970/ https://www.ncbi.nlm.nih.gov/pubmed/29796087 http://dx.doi.org/10.1186/s13068-018-1146-4 |
work_keys_str_mv | AT zhuoshengnan useofbacteriaforimprovingthelignocellulosebiorefineryprocessimportanceofpreerosion AT yanxu useofbacteriaforimprovingthelignocellulosebiorefineryprocessimportanceofpreerosion AT liudan useofbacteriaforimprovingthelignocellulosebiorefineryprocessimportanceofpreerosion AT simengying useofbacteriaforimprovingthelignocellulosebiorefineryprocessimportanceofpreerosion AT zhangkejing useofbacteriaforimprovingthelignocellulosebiorefineryprocessimportanceofpreerosion AT liumingren useofbacteriaforimprovingthelignocellulosebiorefineryprocessimportanceofpreerosion AT pengbing useofbacteriaforimprovingthelignocellulosebiorefineryprocessimportanceofpreerosion AT shiyan useofbacteriaforimprovingthelignocellulosebiorefineryprocessimportanceofpreerosion |