Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities
Abstract Background The polysaccharides in lignocellulosic biomass hold potential for production of biofuels and biochemicals. However, achieving efficient conversion of this resource into fermentable sugars faces challenges, especially when operating at industrially relevant high solid loadings. Wh...
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| Format: | Article |
| Language: | English |
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BMC
2024-03-01
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| Series: | Biotechnology for Biofuels and Bioproducts |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s13068-024-02485-6 |
| _version_ | 1827321496008130560 |
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| author | Camilla F. Angeltveit Anikó Várnai Vincent G. H. Eijsink Svein J. Horn |
| author_facet | Camilla F. Angeltveit Anikó Várnai Vincent G. H. Eijsink Svein J. Horn |
| author_sort | Camilla F. Angeltveit |
| collection | DOAJ |
| description | Abstract Background The polysaccharides in lignocellulosic biomass hold potential for production of biofuels and biochemicals. However, achieving efficient conversion of this resource into fermentable sugars faces challenges, especially when operating at industrially relevant high solid loadings. While it is clear that combining classical hydrolytic enzymes and lytic polysaccharide monooxygenases (LPMOs) is necessary to achieve high saccharification yields, exactly how these enzymes synergize at high solid loadings remains unclear. Results An LPMO-poor cellulase cocktail, Celluclast 1.5 L, was spiked with one or both of two fungal LPMOs from Thermothielavioides terrestris and Thermoascus aurantiacus, TtAA9E and TaAA9A, respectively, to assess their impact on cellulose saccharification efficiency at high dry matter loading, using Avicel and steam-exploded wheat straw as substrates. The results demonstrate that LPMOs can mitigate the reduction in saccharification efficiency associated with high dry matter contents. The positive effect of LPMO inclusion depends on the type of feedstock and the type of LPMO and increases with the increasing dry matter content and reaction time. Furthermore, our results show that chelating free copper, which may leak out of the active site of inactivated LPMOs during saccharification, with EDTA prevents side reactions with in situ generated H2O2 and the reductant (ascorbic acid). Conclusions This study shows that sustaining LPMO activity is vital for efficient cellulose solubilization at high substrate loadings. LPMO cleavage of cellulose at high dry matter loadings results in new chain ends and thus increased water accessibility leading to decrystallization of the substrate, all factors making the substrate more accessible to cellulase action. Additionally, this work highlights the importance of preventing LPMO inactivation and its potential detrimental impact on all enzymes in the reaction. |
| first_indexed | 2024-04-25T01:08:14Z |
| format | Article |
| id | doaj.art-7798df9837b448e2afbec3e5f691d2a5 |
| institution | Directory Open Access Journal |
| issn | 2731-3654 |
| language | English |
| last_indexed | 2024-04-25T01:08:14Z |
| publishDate | 2024-03-01 |
| publisher | BMC |
| record_format | Article |
| series | Biotechnology for Biofuels and Bioproducts |
| spelling | doaj.art-7798df9837b448e2afbec3e5f691d2a52024-03-10T12:08:05ZengBMCBiotechnology for Biofuels and Bioproducts2731-36542024-03-0117111410.1186/s13068-024-02485-6Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activitiesCamilla F. Angeltveit0Anikó Várnai1Vincent G. H. Eijsink2Svein J. Horn3Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU)Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU)Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU)Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU)Abstract Background The polysaccharides in lignocellulosic biomass hold potential for production of biofuels and biochemicals. However, achieving efficient conversion of this resource into fermentable sugars faces challenges, especially when operating at industrially relevant high solid loadings. While it is clear that combining classical hydrolytic enzymes and lytic polysaccharide monooxygenases (LPMOs) is necessary to achieve high saccharification yields, exactly how these enzymes synergize at high solid loadings remains unclear. Results An LPMO-poor cellulase cocktail, Celluclast 1.5 L, was spiked with one or both of two fungal LPMOs from Thermothielavioides terrestris and Thermoascus aurantiacus, TtAA9E and TaAA9A, respectively, to assess their impact on cellulose saccharification efficiency at high dry matter loading, using Avicel and steam-exploded wheat straw as substrates. The results demonstrate that LPMOs can mitigate the reduction in saccharification efficiency associated with high dry matter contents. The positive effect of LPMO inclusion depends on the type of feedstock and the type of LPMO and increases with the increasing dry matter content and reaction time. Furthermore, our results show that chelating free copper, which may leak out of the active site of inactivated LPMOs during saccharification, with EDTA prevents side reactions with in situ generated H2O2 and the reductant (ascorbic acid). Conclusions This study shows that sustaining LPMO activity is vital for efficient cellulose solubilization at high substrate loadings. LPMO cleavage of cellulose at high dry matter loadings results in new chain ends and thus increased water accessibility leading to decrystallization of the substrate, all factors making the substrate more accessible to cellulase action. Additionally, this work highlights the importance of preventing LPMO inactivation and its potential detrimental impact on all enzymes in the reaction.https://doi.org/10.1186/s13068-024-02485-6Lytic polysaccharide monooxygenaseLPMOAA9Cellulolytic enzyme cocktailsEnzymatic saccharificationInactivation |
| spellingShingle | Camilla F. Angeltveit Anikó Várnai Vincent G. H. Eijsink Svein J. Horn Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities Biotechnology for Biofuels and Bioproducts Lytic polysaccharide monooxygenase LPMO AA9 Cellulolytic enzyme cocktails Enzymatic saccharification Inactivation |
| title | Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities |
| title_full | Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities |
| title_fullStr | Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities |
| title_full_unstemmed | Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities |
| title_short | Enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different LPMO activities |
| title_sort | enhancing enzymatic saccharification yields of cellulose at high solid loadings by combining different lpmo activities |
| topic | Lytic polysaccharide monooxygenase LPMO AA9 Cellulolytic enzyme cocktails Enzymatic saccharification Inactivation |
| url | https://doi.org/10.1186/s13068-024-02485-6 |
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