A non-linear model of hydrogen production by Caldicellulosiruptor saccharolyticus for diauxic-like consumption of lignocellulosic sugar mixtures
Abstract Background Caldicellulosiruptor saccharolyticus is an attractive hydrogen producer suitable for growth on various lignocellulosic substrates. The aim of this study was to quantify uptake of pentose and hexose monosaccharides in an industrial substrate and to present a kinetic growth model o...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2018-06-01
|
| Series: | Biotechnology for Biofuels |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s13068-018-1171-3 |
| _version_ | 1818237548654231552 |
|---|---|
| author | Johanna Björkmalm Eoin Byrne Ed W. J. van Niel Karin Willquist |
| author_facet | Johanna Björkmalm Eoin Byrne Ed W. J. van Niel Karin Willquist |
| author_sort | Johanna Björkmalm |
| collection | DOAJ |
| description | Abstract Background Caldicellulosiruptor saccharolyticus is an attractive hydrogen producer suitable for growth on various lignocellulosic substrates. The aim of this study was to quantify uptake of pentose and hexose monosaccharides in an industrial substrate and to present a kinetic growth model of C. saccharolyticus that includes sugar uptake on defined and industrial media. The model is based on Monod and Hill kinetics extended with gas-to-liquid mass transfer and a cybernetic approach to describe diauxic-like growth. Results Mathematical expressions were developed to describe hydrogen production by C. saccharolyticus consuming glucose, xylose, and arabinose. The model parameters were calibrated against batch fermentation data. The experimental data included four different cases: glucose, xylose, sugar mixture, and wheat straw hydrolysate (WSH) fermentations. The fermentations were performed without yeast extract. The substrate uptake rate of C. saccharolyticus on single sugar-defined media was higher on glucose compared to xylose. In contrast, in the defined sugar mixture and WSH, the pentoses were consumed faster than glucose. Subsequently, the cultures entered a lag phase when all pentoses were consumed after which glucose uptake rate increased. This phenomenon suggested a diauxic-like behavior as was deduced from the successive appearance of two peaks in the hydrogen and carbon dioxide productivity. The observation could be described with a modified diauxic model including a second enzyme system with a higher affinity for glucose being expressed when pentose saccharides are consumed. This behavior was more pronounced when WSH was used as substrate. Conclusions The previously observed co-consumption of glucose and pentoses with a preference for the latter was herein confirmed. However, once all pentoses were consumed, C. saccharolyticus most probably expressed another uptake system to account for the observed increased glucose uptake rate. This phenomenon could be quantitatively captured in a kinetic model of the entire diauxic-like growth process. Moreover, the observation indicates a regulation system that has fundamental research relevance, since pentose and glucose uptake in C. saccharolyticus has only been described with ABC transporters, whereas previously reported diauxic growth phenomena have been correlated mainly to PTS systems for sugar uptake. |
| first_indexed | 2024-12-12T12:27:31Z |
| format | Article |
| id | doaj.art-668b52628df240a78172797a4ccdd8a1 |
| institution | Directory Open Access Journal |
| issn | 1754-6834 |
| language | English |
| last_indexed | 2024-12-12T12:27:31Z |
| publishDate | 2018-06-01 |
| publisher | BMC |
| record_format | Article |
| series | Biotechnology for Biofuels |
| spelling | doaj.art-668b52628df240a78172797a4ccdd8a12022-12-22T00:24:30ZengBMCBiotechnology for Biofuels1754-68342018-06-0111111510.1186/s13068-018-1171-3A non-linear model of hydrogen production by Caldicellulosiruptor saccharolyticus for diauxic-like consumption of lignocellulosic sugar mixturesJohanna Björkmalm0Eoin Byrne1Ed W. J. van Niel2Karin Willquist3Department of Energy and Circular Economy, RISE Research Institutes of SwedenDivision of Applied Microbiology, Lund UniversityDivision of Applied Microbiology, Lund UniversityDepartment of Energy and Circular Economy, RISE Research Institutes of SwedenAbstract Background Caldicellulosiruptor saccharolyticus is an attractive hydrogen producer suitable for growth on various lignocellulosic substrates. The aim of this study was to quantify uptake of pentose and hexose monosaccharides in an industrial substrate and to present a kinetic growth model of C. saccharolyticus that includes sugar uptake on defined and industrial media. The model is based on Monod and Hill kinetics extended with gas-to-liquid mass transfer and a cybernetic approach to describe diauxic-like growth. Results Mathematical expressions were developed to describe hydrogen production by C. saccharolyticus consuming glucose, xylose, and arabinose. The model parameters were calibrated against batch fermentation data. The experimental data included four different cases: glucose, xylose, sugar mixture, and wheat straw hydrolysate (WSH) fermentations. The fermentations were performed without yeast extract. The substrate uptake rate of C. saccharolyticus on single sugar-defined media was higher on glucose compared to xylose. In contrast, in the defined sugar mixture and WSH, the pentoses were consumed faster than glucose. Subsequently, the cultures entered a lag phase when all pentoses were consumed after which glucose uptake rate increased. This phenomenon suggested a diauxic-like behavior as was deduced from the successive appearance of two peaks in the hydrogen and carbon dioxide productivity. The observation could be described with a modified diauxic model including a second enzyme system with a higher affinity for glucose being expressed when pentose saccharides are consumed. This behavior was more pronounced when WSH was used as substrate. Conclusions The previously observed co-consumption of glucose and pentoses with a preference for the latter was herein confirmed. However, once all pentoses were consumed, C. saccharolyticus most probably expressed another uptake system to account for the observed increased glucose uptake rate. This phenomenon could be quantitatively captured in a kinetic model of the entire diauxic-like growth process. Moreover, the observation indicates a regulation system that has fundamental research relevance, since pentose and glucose uptake in C. saccharolyticus has only been described with ABC transporters, whereas previously reported diauxic growth phenomena have been correlated mainly to PTS systems for sugar uptake.http://link.springer.com/article/10.1186/s13068-018-1171-3Caldicellulosiruptor saccharolyticusHydrogenKinetic growth modelGlucose uptakeXylose uptakeDiauxic |
| spellingShingle | Johanna Björkmalm Eoin Byrne Ed W. J. van Niel Karin Willquist A non-linear model of hydrogen production by Caldicellulosiruptor saccharolyticus for diauxic-like consumption of lignocellulosic sugar mixtures Biotechnology for Biofuels Caldicellulosiruptor saccharolyticus Hydrogen Kinetic growth model Glucose uptake Xylose uptake Diauxic |
| title | A non-linear model of hydrogen production by Caldicellulosiruptor saccharolyticus for diauxic-like consumption of lignocellulosic sugar mixtures |
| title_full | A non-linear model of hydrogen production by Caldicellulosiruptor saccharolyticus for diauxic-like consumption of lignocellulosic sugar mixtures |
| title_fullStr | A non-linear model of hydrogen production by Caldicellulosiruptor saccharolyticus for diauxic-like consumption of lignocellulosic sugar mixtures |
| title_full_unstemmed | A non-linear model of hydrogen production by Caldicellulosiruptor saccharolyticus for diauxic-like consumption of lignocellulosic sugar mixtures |
| title_short | A non-linear model of hydrogen production by Caldicellulosiruptor saccharolyticus for diauxic-like consumption of lignocellulosic sugar mixtures |
| title_sort | non linear model of hydrogen production by caldicellulosiruptor saccharolyticus for diauxic like consumption of lignocellulosic sugar mixtures |
| topic | Caldicellulosiruptor saccharolyticus Hydrogen Kinetic growth model Glucose uptake Xylose uptake Diauxic |
| url | http://link.springer.com/article/10.1186/s13068-018-1171-3 |
| work_keys_str_mv | AT johannabjorkmalm anonlinearmodelofhydrogenproductionbycaldicellulosiruptorsaccharolyticusfordiauxiclikeconsumptionoflignocellulosicsugarmixtures AT eoinbyrne anonlinearmodelofhydrogenproductionbycaldicellulosiruptorsaccharolyticusfordiauxiclikeconsumptionoflignocellulosicsugarmixtures AT edwjvanniel anonlinearmodelofhydrogenproductionbycaldicellulosiruptorsaccharolyticusfordiauxiclikeconsumptionoflignocellulosicsugarmixtures AT karinwillquist anonlinearmodelofhydrogenproductionbycaldicellulosiruptorsaccharolyticusfordiauxiclikeconsumptionoflignocellulosicsugarmixtures AT johannabjorkmalm nonlinearmodelofhydrogenproductionbycaldicellulosiruptorsaccharolyticusfordiauxiclikeconsumptionoflignocellulosicsugarmixtures AT eoinbyrne nonlinearmodelofhydrogenproductionbycaldicellulosiruptorsaccharolyticusfordiauxiclikeconsumptionoflignocellulosicsugarmixtures AT edwjvanniel nonlinearmodelofhydrogenproductionbycaldicellulosiruptorsaccharolyticusfordiauxiclikeconsumptionoflignocellulosicsugarmixtures AT karinwillquist nonlinearmodelofhydrogenproductionbycaldicellulosiruptorsaccharolyticusfordiauxiclikeconsumptionoflignocellulosicsugarmixtures |