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Xu J, Li H, Alam MA, Muhammad G, Lv Y, Zhao A, Zhang S, Xiong W. Employing Cationic Kraft Lignin as Additive to Enhance Enzymatic Hydrolysis of Corn Stalk. Polymers (Basel) 2023; 15:polym15091991. [PMID: 37177139 PMCID: PMC10180774 DOI: 10.3390/polym15091991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/10/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023] Open
Abstract
A water-soluble cationic kraft lignin (named JLQKL50), synthesized by combining quaternization and crosslinking reactions, was used as an additive to enhance the enzymatic hydrolysis of dilute-alkali-pretreated corn stalk. The chemical constitution of JLQKL50 was investigated by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance (NMR) and 13C NMR spectroscopy, and elemental analysis. The enzymatic hydrolysis efficiency of corn stalk at solid content of 10% (w/v) was significantly improved from 70.67% to 78.88% after 24 h when JLQKL50 was added at a concentration of 2 g/L. Meanwhile, the enzymatic hydrolysis efficiency after 72 h reached 91.11% with 10 FPU/g of cellulase and 97.92% with 15 FPU/g of cellulase. In addition, JLQKL50 was found capable of extending the pH and temperature ranges of enzymatic hydrolysis to maintain high efficiency (higher than 70%). The decrease in cellulase activity under vigorous stirring with the addition of JLQKL50 was 17.4%, which was much lower than that (29.7%) without JLQKL50. The addition of JLQKL50 reduced the nonproductive adsorption of cellulase on the lignin substrate and improved the longevity, dispersity, and stability of the cellulase by enabling electrostatic repulsion. Therefore, the enzymatic hydrolysis of the corn stalk was enhanced. This study paves the way for the design of sustainable lignin-based additives to boost the enzymatic hydrolysis of lignocellulosic biomass.
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Affiliation(s)
- Jingliang Xu
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
- Henan Center for Outstanding Overseas Scientists, Zhengzhou 450001, China
| | - Huihua Li
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Md Asraful Alam
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Gul Muhammad
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Yongkun Lv
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Anqi Zhao
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Shen Zhang
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Wenlong Xiong
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
- Henan Center for Outstanding Overseas Scientists, Zhengzhou 450001, China
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Cao C, Zhu Z, Xu C, Gong W, Zhou Y, Yan L, Hu Z, Xie C, Peng Y. Improving saccharification of ramie stalks by synergistic effect of in-house cellulolytic enzymes consortium. AMB Express 2022; 12:119. [PMID: 36114307 PMCID: PMC9481857 DOI: 10.1186/s13568-022-01453-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 08/18/2022] [Indexed: 11/24/2022] Open
Abstract
The high cost of cellulase is one of the main obstacles hindering the large-scale biorefining of lignocellulosic biomass. Therefore, developing efficient method for preparation of cellulase is promising. In the present study, the production of cellulase by Trichoderma reesei, Trichoderma harzianum, and Aspergillus niger was optimized, and the synergistic effect of these cellulase on enzymatic hydrolysis of pretreated ramie stalks was also evaluated. The maximum CMCase (Carboxymethyl Cellulase) and filter paper activity (FPA) produced by T. reesei reached to 3.12 IU/mL and 0.13 IU/mL, respectively. The maximum activities of CMCase (3.68 IU/mL), FPA (0.04 IU/mL) and β-glucosidase (8.44 IU/mL) were obtained from A. niger. The results also showed that under the premise of the same FPA activity, the contribution of β-glucosidase activity to yield of reducing sugar was greater than that of CMCase. Besides, cellulase produced by T. reesei and A. niger had the best synergistic effect on enzymatic hydrolysis of pretreated ramie stalks. The highest reducing sugars yield (417 mg/g dry substrate) was achieved when enzyme cocktail was prepared at the ratio of 1:1, which was 1.36–3.35 folds higher than that of different single enzymes. The present research has provided a novel method for efficient preparation of enzymes consortium for enzymatic hydrolysis of ramie stalks.
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Guo Y, Liu G, Ning Y, Li X, Hu S, Zhao J, Qu Y. Production of cellulosic ethanol and value-added products from corn fiber. BIORESOUR BIOPROCESS 2022; 9:81. [PMID: 38647596 PMCID: PMC10991675 DOI: 10.1186/s40643-022-00573-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/03/2022] [Indexed: 11/10/2022] Open
Abstract
Corn fiber, a by-product from the corn processing industry, mainly composed of residual starch, cellulose, and hemicelluloses, is a promising raw material for producing cellulosic ethanol and value-added products due to its abundant reserves and low costs of collection and transportation. Now, several technologies for the production of cellulosic ethanol from corn fiber have been reported, such as the D3MAX process, Cellerate™ process, etc., and part of the technologies have also been used in industrial production in the United States. The ethanol yields range from 64 to 91% of the theoretical maximum, depending on different production processes. Because of the multicomponent of corn fiber and the complex structures highly substituted by a variety of side chains in hemicelluloses of corn fiber, however, there are many challenges in cellulosic ethanol production from corn fiber, such as the low conversion of hemicelluloses to fermentable sugars in enzymatic hydrolysis, high production of inhibitors during pretreatment, etc. Some technologies, including an effective pretreatment process for minimizing inhibitors production and maximizing fermentable sugars recovery, production of enzyme preparations with suitable protein compositions, and the engineering of microorganisms capable of fermenting hexose and pentose in hydrolysates and inhibitors tolerance, etc., need to be further developed. The process integration of cellulosic ethanol and value-added products also needs to be developed to improve the economic benefits of the whole process. This review summarizes the status and progresses of cellulosic ethanol production and potential value-added products from corn fiber and presents some challenges in this field at present.
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Affiliation(s)
- Yingjie Guo
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China
| | - Yanchun Ning
- Research Institute of Jilin Petrochemical Company, PetroChina, No. 27, Zunyidong Road, Jilin City, 132021, Jilin, China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China.
| | - Shiyang Hu
- Research Institute of Jilin Petrochemical Company, PetroChina, No. 27, Zunyidong Road, Jilin City, 132021, Jilin, China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China.
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China
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Jia H, Feng X, Huang J, Guo Y, Zhang D, Li X, Zhao J. Recombinant Family 1 Carbohydrate-Binding Modules Derived From Fungal Cellulase Enhance Enzymatic Degradation of Lignocellulose as Novel Effective Accessory Protein. Front Microbiol 2022; 13:876466. [PMID: 35898911 PMCID: PMC9309510 DOI: 10.3389/fmicb.2022.876466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/09/2022] [Indexed: 11/23/2022] Open
Abstract
Fungal cellulases usually contain a family 1 carbohydrate-binding module (CBM1), and its role was considered to recognize the substrate specifically. This study testified that the CBM1s derived from cellobiohydrolase I of Trichoderma reesei, Penicillium oxalicum, and Penicillium funiculosum could be used as an effective accessory protein in cellulase cocktails to enhance the saccharification of lignocellulose, and its enhancement effect was significantly superior to some reported accessory proteins, such as bovine serum albumin (BSA). The promoting effects of the CBM1s were related to not only the CBM1 sources and protein dosages, but also the substrate characteristics and solid consistency during enzymatic hydrolysis. The adsorption capacity of the CBM1s, the adsorption kinetic of TrCBM from T. reesei and cellobiohydrolase, endoglucanase, and β-glucosidase from P. oxalicum, and the effect of adding TrCBM on enzyme activities of free cellulases in the hydrolysis system were investigated, and the binding conformations and affinities of CBM1s to cellulose and lignin were predicted by molecular docking. It was speculated that the higher affinity of the CBM1s to lignin than cellulases could potentially enable the CBM1s to displace cellulase adsorbed on lignin or to preferentially adsorb onto lignin to avoid ineffective adsorption of cellulase onto lignin, which enhanced cellulase system efficiency during enzymatic hydrolysis of lignocellulose.
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Affiliation(s)
- Hexue Jia
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Xiaoting Feng
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Jiamin Huang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Yingjie Guo
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Daolei Zhang
- School of Bioengineering, Shandong Polytechnic, Jinan, China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
- *Correspondence: Xuezhi Li,
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
- Jian Zhao,
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Du J, Liang J, Zhang X, Wang J, Li W, Song P, Feng X. Identifying the negative cooperation between major inhibitors of cellulase activity and minimizing their inhibitory potential during hydrolysis of acid-pretreated corn stover. BIORESOURCE TECHNOLOGY 2022; 343:126113. [PMID: 34648965 DOI: 10.1016/j.biortech.2021.126113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Soluble compounds produced during the enzymatic hydrolysis of lignocelluloses hampers cellulose conversion. Cellobiose and vanillin most severely inhibited the effect of cellobiohydrolase I. A concentration-dependent negative cooperative effect was found between cellobiose and vanillin. The combined inhibitory effect was about 83.5% of the cellobiose and 88.1% of the vanillin when their concentration was 20 mg/ml. However, the negative synergy could be eliminated by excessive enzyme loading. Differences in their binding sites on the catalytic domain of cellobiohydrolase I lead to negative synergistic inhibition, which should be considered in devising strategies to alleviate this effect. Combined β-glucosidase and PEG addition at an appropriate dose was feasible to balance cost and hydrolytic efficiency. To achieve efficient hydrolysis, especially at high solid concentrations, it is important to understand the synergistic inhibition between these inhibitors.
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Affiliation(s)
- Jian Du
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang 277160, China.
| | - Jingrui Liang
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang 277160, China
| | - Xiujun Zhang
- College of Biological Science and Technology, Jinan University, Jinan 250024, China
| | - Jinglong Wang
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang 277160, China
| | - Wei Li
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang 277160, China
| | - Peixue Song
- College of City and Architectural Engineering, Zaozhuang University, Zaozhuang 277160, China
| | - Xiaohui Feng
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang 277160, China
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Jia H, Sun W, Li X, Zhao J. Cellulose induced protein 1 (Cip1) from Trichoderma reesei enhances the enzymatic hydrolysis of pretreated lignocellulose. Microb Cell Fact 2021; 20:136. [PMID: 34281536 PMCID: PMC8287770 DOI: 10.1186/s12934-021-01625-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 07/02/2021] [Indexed: 11/10/2022] Open
Abstract
Background Trichoderma reesei is currently the main strain for the commercial production of cellulase. Cellulose induced protein 1 (Cip1) is one of the most abundant proteins in extracellular proteins of T. reesei. Reported literatures about Cip1 mainly focused on the regulation of Cip1 and its possible enzyme activities, but the effect of Cip1 on the enzymatic hydrolysis of lignocellulose and possible mechanism have not still been reported. Results In this study, Cip1 from T. reesei was cloned, expressed and purified, and its effects on enzymatic hydrolysis of several different pretreated lignocellulose were investigated. It was found that Cip1 could promote the enzymatic hydrolysis of pretreated lignocellulose, and the promoting effect was significantly better than that of bovine serum albumin (BSA). And especially for the lignocellulosic substrate with high lignin content such as liquid hot water pretreated corn stover and corncob residue, the promoting effect of Cip1 was even better than that of the commercial cellulase when adding equal amount protein. It was also showed that the metal ions Zn2+ and Cu2+ influenced the promoting effect on enzymatic hydrolysis. The Cip1 protein had no lyase activity, but it could destroy the crystal structure of cellulose and reduce the non-productive adsorption of cellulase on lignin, which partly interpreted the promoting effect of Cip1 on enzymatic hydrolysis of lignocellulose. Conclusion The Cip1 from T. reesei could significantly promote the enzymatic hydrolysis of pretreated lignocellulose, and the promotion of Cip1 was even higher than that of commercial cellulase in the enzymatic hydrolysis of the substrates with high lignin content. This study will help us to better optimize cellulase to improve its ability to degrade lignocellulose, thereby reducing the cost of enzymes required for enzymatic hydrolysis. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-021-01625-z.
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Affiliation(s)
- Hexue Jia
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China
| | - Wan Sun
- National Glycoengineering Research Center, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China.
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China.
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7
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Pihlajaniemi V, Kallioinen A, Sipponen MH, Nyyssölä A. Modeling and optimization of polyethylene glycol (PEG) addition for cost-efficient enzymatic hydrolysis of lignocellulose. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2020.107894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Zhang R. Functional characterization of cellulose-degrading AA9 lytic polysaccharide monooxygenases and their potential exploitation. Appl Microbiol Biotechnol 2020; 104:3229-3243. [PMID: 32076777 DOI: 10.1007/s00253-020-10467-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 12/25/2019] [Accepted: 02/12/2020] [Indexed: 01/05/2023]
Abstract
Cellulose-degrading auxiliary activity family 9 (AA9) lytic polysaccharide monooxygenases (LPMOs) are known to be widely distributed among filamentous fungi and participate in the degradation of lignocellulose via the oxidative cleavage of celluloses, cello-oligosaccharides, or hemicelluloses. AA9 LPMOs have been reported to have extensive interactions with not only cellulases but also oxidases. The addition of AA9 LPMOs can greatly reduce the amount of cellulase needed for saccharification and increase the yield of glucose. The discovery of AA9 LPMOs has greatly changed our understanding of how fungi degrade cellulose. In this review, apart from summarizing the recent discoveries related to their catalytic reaction, functional diversity, and practical applications, the stability, expression system, and protein engineering of AA9 LPMOs are reviewed for the first time. This review may provide a reference value to further broaden the substrate range of AA9 LPMOs, expand the scope of their practical applications, and realize their customization for industrial utilization.Key Points• The stability and expression system of AA9 LPMOs are reviewed for the first time.• The protein engineering of AA9 LPMOs is systematically summarized for the first time.• The latest research results on the catalytic mechanism of AA9 LPMOs are summarized.• The application of AA9 LPMOs and their relationship with other enzymes are reviewed.
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Affiliation(s)
- Ruiqin Zhang
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China.
- Department of Bioengineering, Huainan Normal University, No. 278 Xueyuannan Road, Huainan, 232038, China.
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Du J, Liang J, Gao X, Liu G, Qu Y. Optimization of an artificial cellulase cocktail for high-solids enzymatic hydrolysis of cellulosic materials with different pretreatment methods. BIORESOURCE TECHNOLOGY 2020; 295:122272. [PMID: 31669875 DOI: 10.1016/j.biortech.2019.122272] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 10/14/2019] [Accepted: 10/15/2019] [Indexed: 05/17/2023]
Abstract
Optimization of the composition of cellulase mixtures is an effective strategy to improve their hydrolytic efficiency and reduce protein demand during enzymatic degradation of lignocelluloses. In this study, the mixture design method was used to optimize the ratios of endoglucanase II (EG II), cellobiohydrolase I (CBH I) and β-glucosidase I (BG I) from Penicillium oxalicum in an artificial cellulase mixture for the hydrolysis of six different cellulosic materials. The optimal composition of enzyme mixture was distinctly different among not only cellulosic materials with different pretreatment methods but hydrolyses at different solids concentrations. CBH I was most critical for the hydrolysis of two acid-pretreated materials, probably due to its strong adsorption on lignin. A higher proportion of EG II was needed for the hydrolysis of ammonium sulfite pretreated wheat straw. The requirements of specific cellulase components were more pronounced at high solids concentrations, highlighting the importance of considering solids loading when optimizing cellulase cocktails.
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Affiliation(s)
- Jian Du
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang 277160, China; State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Jingrui Liang
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang 277160, China
| | - Xiuhua Gao
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang 277160, China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China.
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
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Chylenski P, Bissaro B, Sørlie M, Røhr ÅK, Várnai A, Horn SJ, Eijsink VG. Lytic Polysaccharide Monooxygenases in Enzymatic Processing of Lignocellulosic Biomass. ACS Catal 2019. [DOI: 10.1021/acscatal.9b00246] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Piotr Chylenski
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Bastien Bissaro
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Morten Sørlie
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Åsmund K. Røhr
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Svein J. Horn
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
| | - Vincent G.H. Eijsink
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
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Kont R, Pihlajaniemi V, Borisova AS, Aro N, Marjamaa K, Loogen J, Büchs J, Eijsink VGH, Kruus K, Väljamäe P. The liquid fraction from hydrothermal pretreatment of wheat straw provides lytic polysaccharide monooxygenases with both electrons and H 2O 2 co-substrate. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:235. [PMID: 31624497 PMCID: PMC6781412 DOI: 10.1186/s13068-019-1578-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 09/24/2019] [Indexed: 05/18/2023]
Abstract
BACKGROUND Enzyme-aided valorization of lignocellulose represents a green and sustainable alternative to the traditional chemical industry. The recently discovered lytic polysaccharide monooxygenases (LPMOs) are important components of the state-of-the art enzyme cocktails for cellulose conversion. Yet, these monocopper enzymes are poorly characterized in terms of their kinetics, as exemplified by the growing evidence for that H2O2 may be a more efficient co-substrate for LPMOs than O2. LPMOs need external electron donors and one key question of relevance for bioprocess development is whether the required reducing power may be provided by the lignocellulosic substrate. RESULTS Here, we show that the liquid fraction (LF) resulting from hydrothermal pretreatment of wheat straw supports LPMO activity on both chitin and cellulose. The initial, transient activity burst of the LPMO reaction was caused by the H2O2 present in the LF before addition of LPMO, while the steady-state rate of LPMO reaction was limited by the LPMO-independent production of H2O2 in the LF. H2O2 is an intermediate of LF oxidation as evidenced by a slow H2O2 accumulation in LF, despite high H2O2 production rates. This H2O2 scavenging ability of LF is important since high concentrations of H2O2 may lead to irreversible inactivation of LPMOs. CONCLUSIONS Our results support the growing understanding that fine-tuned control over the rates of H2O2 production and consumption in different, enzymatic and non-enzymatic reactions is essential for harnessing the full catalytic potential of LPMOs in lignocellulose valorization.
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Affiliation(s)
- Riin Kont
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | | | | | - Nina Aro
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Kaisa Marjamaa
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Judith Loogen
- Department of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Aachen, Germany
| | - Jochen Büchs
- Department of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Aachen, Germany
| | | | - Kristiina Kruus
- VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
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12
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Liu G, Qu Y. Engineering of filamentous fungi for efficient conversion of lignocellulose: Tools, recent advances and prospects. Biotechnol Adv 2018; 37:519-529. [PMID: 30576717 DOI: 10.1016/j.biotechadv.2018.12.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 01/17/2023]
Abstract
Filamentous fungi, as the main producers of lignocellulolytic enzymes in industry, need to be engineered to improve the economy of large-scale lignocellulose conversion. Investigation of the cellular processes involved in lignocellulolytic enzyme production, as well as optimization of enzyme mixtures for higher hydrolysis efficiency, have provided effective targets for the engineering of lignocellulolytic fungi. Recently, the development of efficient genetic manipulation systems in several lignocellulolytic fungi opens up the possibility of systems engineering of these strains. Here, we review the recent progresses made in the engineering of lignocellulolytic fungi and highlight the research gaps in this area.
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Affiliation(s)
- Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; National Glycoengineering Research Center, Shandong University, Qingdao 266237, China.
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13
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Bissaro B, Várnai A, Røhr ÅK, Eijsink VGH. Oxidoreductases and Reactive Oxygen Species in Conversion of Lignocellulosic Biomass. Microbiol Mol Biol Rev 2018; 82:e00029-18. [PMID: 30257993 PMCID: PMC6298611 DOI: 10.1128/mmbr.00029-18] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Biomass constitutes an appealing alternative to fossil resources for the production of materials and energy. The abundance and attractiveness of vegetal biomass come along with challenges pertaining to the intricacy of its structure, evolved during billions of years to face and resist abiotic and biotic attacks. To achieve the daunting goal of plant cell wall decomposition, microorganisms have developed many (enzymatic) strategies, from which we seek inspiration to develop biotechnological processes. A major breakthrough in the field has been the discovery of enzymes today known as lytic polysaccharide monooxygenases (LPMOs), which, by catalyzing the oxidative cleavage of recalcitrant polysaccharides, allow canonical hydrolytic enzymes to depolymerize the biomass more efficiently. Very recently, it has been shown that LPMOs are not classical monooxygenases in that they can also use hydrogen peroxide (H2O2) as an oxidant. This discovery calls for a revision of our understanding of how lignocellulolytic enzymes are connected since H2O2 is produced and used by several of them. The first part of this review is dedicated to the LPMO paradigm, describing knowns, unknowns, and uncertainties. We then present different lignocellulolytic redox systems, enzymatic or not, that depend on fluxes of reactive oxygen species (ROS). Based on an assessment of these putatively interconnected systems, we suggest that fine-tuning of H2O2 levels and proximity between sites of H2O2 production and consumption are important for fungal biomass conversion. In the last part of this review, we discuss how our evolving understanding of redox processes involved in biomass depolymerization may translate into industrial applications.
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Affiliation(s)
- Bastien Bissaro
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | - Åsmund K Røhr
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
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