Records |
Author |
Broos, W.; Wittner, N.; Geerts, J.; Dries, J.; Vlaeminck, S.E.; Gunde-Cimerman, N.; Richel, A.; Cornet, I. |
Title |
Evaluation of lignocellulosic wastewater valorization with the oleaginous yeasts R. kratochvilovae EXF7516 and C. oleaginosum ATCC 20509 |
Type |
A1 Journal article |
Year |
2022 |
Publication |
Fermentation |
Abbreviated Journal |
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Volume |
8 |
Issue |
5 |
Pages |
204-221 |
Keywords |
A1 Journal article; Pharmacology. Therapy; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE) |
Abstract |
During the conversion of lignocellulose, phenolic wastewaters are generated. Therefore, researchers have investigated wastewater valorization processes in which these pollutants are converted to chemicals, i.e., lipids. However, wastewaters are lean feedstocks, so these valorization processes in research typically require the addition of large quantities of sugars and sterilization, which increase costs. This paper investigates a repeated batch fermentation strategy with Rhodotorula kratochvilovae EXF7516 and Cutaneotrichosporon oleaginosum ATCC 20509, without these requirements. The pollutant removal and its conversion to microbial oil were evaluated. Because of the presence of non-monomeric substrates, the ligninolytic enzyme activity was also investigated. The repeated batch fermentation strategy was successful, as more lipids accumulated every cycle, up to a total of 5.4 g/L (23% cell dry weight). In addition, the yeasts consumed up to 87% of monomeric substrates, i.e., sugars, aromatics, and organics acids, and up to 23% of non-monomeric substrates, i.e., partially degraded xylan, lignin, cellulose. Interestingly, lipid production was only observed during the harvest phase of each cycle, as the cells experienced stress, possibly due to oxygen limitation. This work presents the first results on the feasibility of valorizing non-sterilized lignocellulosic wastewater with R. kratochvilovae and C. oleaginosum using a cost-effective repeated batch strategy. |
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Wos |
000801796000001 |
Publication Date |
2022-05-01 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2311-5637 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited ![sorted by Times cited field, ascending order (up)](img/sort_asc.gif) |
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Open Access |
OpenAccess |
Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:187883 |
Serial |
7157 |
Permanent link to this record |
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Author |
Wittner, N.; Slezsák, J.; Broos, W.; Geerts, J.; Gergely, S.; Vlaeminck, S.E.; Cornet, I. |
Title |
Rapid lignin quantification for fungal wood pretreatment by ATR-FTIR spectroscopy |
Type |
A1 Journal article |
Year |
2023 |
Publication |
Spectrochimica acta: part A: molecular and biomolecular spectroscopy |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
121912 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE) |
Abstract |
Lignin determination in lignocellulose with the conventional two-step acid hydrolysis method is highly laborious and time-consuming. However, its quantification is crucial to monitor fungal pretreatment of wood, as the increase of acid-insoluble lignin (AIL) degradation linearly correlates with the achievable enzymatic saccharification yield. Therefore, in this study, a new attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy method was developed to track fungal delignification in an easy and rapid manner. Partial least square regression (PLSR) with cross-validation (CV) was applied to correlate the ATR-FTIR spectra with the AIL content (19.9%–27.1%). After variable selection and normalization, a PLSR model with a high coefficient of determination ( |
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Place of Publication |
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Wos |
000985309100010 |
Publication Date |
2022-09-22 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1386-1425 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.4 |
Times cited ![sorted by Times cited field, ascending order (up)](img/sort_asc.gif) |
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Open Access |
OpenAccess |
Notes |
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Approved |
Most recent IF: 4.4; 2023 IF: 2.536 |
Call Number |
UA @ admin @ c:irua:190328 |
Serial |
7201 |
Permanent link to this record |
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Author |
Wittner, N. |
Title |
Improving and characterising solid-state fungal pretreatment by Phanerochaete chrysosporium for sugar production from poplar wood |
Type |
Doctoral thesis |
Year |
2023 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
206 p. |
Keywords |
Doctoral thesis; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE) |
Abstract |
Pretreatment is a critical step in the conversion of lignocellulose into biofuels and biochemicals. During pretreatment, the recalcitrance of lignocellulose is reduced, e.g. by removing lignin, thereby making the carbohydrates more accessible for enzymatic saccharification. Fungal delignification by white-rot fungi is a biotechnological alternative to chemical/physicochemical methods, which is carried out in solid-state fermentation with mild reaction conditions and without the formation of microbial inhibitors. However, fungal pretreatment presents some challenges, such as long pretreatment time, non-selective and low delignification, low enzymatic digestibility and feedstock sterilisation requirement, making its commercial implementation challenging compared to conventional methods. This study investigates the possibility of improving and characterising the solid-state fungal pretreatment of poplar wood by Phanerochaete chrysosporium. The individual and combined effects of MnSO4 and CuSO4 supplements on the delignification of sterilised wood are investigated using response surface methodology to improve the degree and selectivity of fungal delignification. Spore-inoculated solid-state fermentations are carried out for 4 weeks in sterile vented bottles. The mechanism of the concerted action of the metal ions on lignin degradation is then elucidated by relating fungal growth and ligninolytic enzyme activities to lignocellulose degradation as a function of pretreatment time. The optimised metal-supplemented system is then applied to the pretreatment of non-sterilised wood using different inoculation techniques (spores and pre-colonised substrate), nutrients (metal ions with or without glucose and sodium nitrate) and cultivation environments (sterile aerated bottles and open trays). The fermentations are then characterised using infrared spectroscopy, in particular NIR and ATR-FTIR spectroscopy, with the aim of developing rapid lignin quantification methods as an alternative to conventional wet chemical methods. Finally, the feasibility of producing fermentable sugars from sterilised and non-sterilised poplar wood using fungal pretreatment is evaluated through a techno-economic analysis. Supplementing the pretreatment system with 2.01 µmol CuSO4 and 0.77 µmol MnSO4 g-1 wood resulted in 1.9-fold higher lignin degradation, 2.3-fold higher delignification selectivity value and 2.9-fold higher glucose yield. The improved delignification could be explained by the concerted action of Mn2+ and Cu2+ ions, with Mn2+ ions inducing and Cu2+ prolonging manganese peroxidase production responsible for delignification. Fungal pretreatment at non-sterile conditions was obtained using trays in a simple solid-state fermentation set-up without sterile aeration. A 1:3 ratio of pre-colonised and untreated wood was applied for inoculation and only Cu2+, Mn2+ and sodium nitrate as supplements. Remarkably, this technology resulted in a comparably high glucose yield (28.51 ± 0.28%) to the traditional method using sterilised wood, sterile aeration and spores as inoculum, while reducing the amount of wood to be sterilised by 71.2%. Infrared spectroscopy-based methods with high coefficients of determination (R_CV |
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Additional Links |
UA library record |
Impact Factor |
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Times cited ![sorted by Times cited field, ascending order (up)](img/sort_asc.gif) |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:197185 |
Serial |
8883 |
Permanent link to this record |
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Author |
Wittner, N.; Vasilakou, K.; Broos, W.; Vlaeminck, S.E.; Nimmegeers, P.; Cornet, I. |
Title |
Investigating the technical and economic potential of solid-state fungal pretreatment at nonsterile conditions for sugar production from poplar wood |
Type |
A1 Journal article |
Year |
2023 |
Publication |
Industrial and engineering chemistry research |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
1-11 |
Keywords |
A1 Journal article; Economics; Engineering sciences. Technology; Engineering Management (ENM); Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE); Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS) |
Abstract |
Pretreatment is crucial for the conversion of lignocellulose to biofuels. Unlike conventional chemical/physicochemical methods, fungal pretreatment uses white-rot fungi and mild reaction conditions. However, challenges, including substrate sterilization, long duration, and low sugar yields associated with this method, contribute to lower techno-economic performance, an aspect that has rarely been investigated. This study aimed to evaluate the feasibility of fungal pretreatment of nonsterilized poplar wood. Various factors, including inoculum types, fermentation supplements, and cultivation methods, were investigated to optimize the process. A techno-economic assessment of the optimized processes was performed at a full biorefinery scale. The scenario using nonsterilized wood as a substrate, precolonized wood as an inoculum, and a 4 week pretreatment showed a 14.5% reduction in sugar production costs (€2.15/kg) compared to using sterilized wood. Although the evaluation of nonsterilized wood pretreatment showed promising cost reductions, fungal pretreatment remained more expensive than conventional methods due to the significant capital investment required. |
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Wos |
001102138000001 |
Publication Date |
2023-10-25 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0888-5885; 1520-5045 |
ISBN |
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Additional Links |
UA library record; WoS full record |
Impact Factor |
4.2 |
Times cited ![sorted by Times cited field, ascending order (up)](img/sort_asc.gif) |
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Open Access |
Not_Open_Access: Available from 24.04.2024 |
Notes |
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Approved |
Most recent IF: 4.2; 2023 IF: 2.843 |
Call Number |
UA @ admin @ c:irua:200155 |
Serial |
8891 |
Permanent link to this record |
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Author |
Wittner, N.; Gergely, S.; Slezsák, J.; Broos, W.; Vlaeminck, S.E.; Cornet, I. |
Title |
Follow-up of solid-state fungal wood pretreatment by a novel near-infrared spectroscopy-based lignin calibration model |
Type |
A1 Journal article |
Year |
2023 |
Publication |
Journal of microbiological methods |
Abbreviated Journal |
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Volume |
208 |
Issue |
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Pages |
106725-106727 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE) |
Abstract |
Lignin removal plays a crucial role in the efficient bioconversion of lignocellulose to fermentable sugars. As a delignification process, fungal pretreatment has gained great interest due to its environmental friendliness and low energy consumption. In our previous study, a positive linear correlation between acid-insoluble lignin degradation and the achievable enzymatic saccharification yield has been found, hereby highlighting the importance of the close follow-up of lignin degradation during the solid-state fungal pretreatment process. However, the standard quantification of lignin, which relies on the two-step acid hydrolysis of the biomass, is highly laborious and time-consuming. Vibrational spectroscopy has been proven as a fast and easy alternative; however, it has not been extensively researched on lignocellulose subjected to solid-state fungal pretreatment. Therefore, the present study examined the suitability of near-infrared spectroscopy (NIR) for the rapid and easy assessment of lignin content in poplar wood pretreated with Phanerochaete chrysosporium. Furthermore, the predictive power of the obtained calibration model and the recently published ATR-FTIR spectroscopy-based model were compared for the first time using the same fungus-treated wood data set. PLSR was used to correlate the NIR spectra to the acid-insoluble lignin contents (19.9%-27.1%) of pretreated wood. After normalization and second derivation, a PLSR model with a good coefficient of determination (RCV2 = 0.89) and a low root mean square error (RMSECV = 0.55%) were obtained despite the heterogeneous nature of the fungal solid-state fermentation. The performance of this PLSR model was comparably good to the one obtained by ATR-FTIR (RCV2 = 0.87) while it required more extensive spectral pre-processing. In conclusion, both methods will be highly useful for the high-throughput and user-friendly monitoring of lignin degradation in a solid-state fungal pretreatment-based biorefinery concept. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Wos |
000983287400001 |
Publication Date |
2023-04-13 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0167-7012 |
ISBN |
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Additional Links |
UA library record; WoS full record |
Impact Factor |
2.2 |
Times cited ![sorted by Times cited field, ascending order (up)](img/sort_asc.gif) |
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Open Access |
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Notes |
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Approved |
Most recent IF: 2.2; 2023 IF: 1.79 |
Call Number |
UA @ admin @ c:irua:195814 |
Serial |
9038 |
Permanent link to this record |
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Author |
Broos, W.; Wittner, N.; Dries, J.; Vlaeminck, S.E.; Gunde-Cimerman, N.; Cornet, I. |
Title |
Rhodotorula kratochvilovae outperforms Cutaneotrichosporon oleaginosum in the valorisation of lignocellulosic wastewater to microbial oil |
Type |
A1 Journal article |
Year |
2024 |
Publication |
Process biochemistry (1991) |
Abbreviated Journal |
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Volume |
137 |
Issue |
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Pages |
229-238 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE) |
Abstract |
Rhodotorula kratochvilovae has shown to be a promising species for microbial oil production from lignin-derived compounds. Yet, information on R. kratochvilovae’s detoxification and microbial oil production is scarce. This study investigated the growth and microbial oil production on the phenolic-containing effluent from poplar steam explosion and its detoxification with five R. kratochvilovae strains (EXF11626, EXF9590, EXF7516, EXF3697, EXF3471) and compared them with Cutaneotrichosporon oleaginosum. The R. kratochvilovae strains reached a maximum growth rate up to four times higher than C. oleaginosum. Furthermore, all R. kratochvilovae strains generally degraded phenolics more rapidly and to a larger extent than C. oleaginosum. However, the diluted substrate limited the lipid production by all strains as the maximum lipid content and titre were 10.5% CDW and 0.40 g/L, respectively. Therefore, future work should focus on increasing lipid production by using advanced fermentation strategies and stimulating the enzyme excretion by the yeasts for complex substrate breakdown. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Wos |
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Publication Date |
2024-01-13 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1359-5113 |
ISBN |
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Additional Links |
UA library record |
Impact Factor |
4.4 |
Times cited ![sorted by Times cited field, ascending order (up)](img/sort_asc.gif) |
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Open Access |
Not_Open_Access |
Notes |
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Approved |
Most recent IF: 4.4; 2024 IF: 2.497 |
Call Number |
UA @ admin @ c:irua:202365 |
Serial |
9087 |
Permanent link to this record |