Inhibitions of microbial fermentation by residual reductive lignin oil: Concerns on the bioconversion of reductive catalytic fractionated carbohydrate pulp

Wu, Yilu; Wen, Jieyi; Su, Changsheng; Jiang, Chenhang; Zhang, Changwei; Wang, Yankun; Jiang, Yong; Ren, Wenqiang; Qin, Peiyong; Cai, Di

doi:10.1016/j.cej.2022.139267

Cited by 18 publications

(11 citation statements)

References 74 publications

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“…14 Besides these solubilized carbohydrates, sugar oligomers and smaller amounts of glycerol, ethylene glycol, and propylene glycol were identified in the composition of the water fraction after RCF. 4,8,14,39,40 Although research has started to show interest in this water fraction, 41 exploration of its potential as a valuable source of sugar(-derived products) for use in any downstream process has not been done. RCF has proven successful in the refinement of forestry waste feedstock into value-added lignin oil and a carbohydrate pulp.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Another aspect that complicates the comparison of data is the different manners of bioethanol yield calculations, either based on the carbohydrate content of the refined pulp 16 or the sugars released after saccharification. 41 In fact, the sugars solubilized during RCF are neglected in both of these yield calculations and, instead, should also be included in any report on biorefineries to depict realistic product yields that are based on the raw biomass feedstock. This again pinpoints the issue of integrating solubilized carbohydrate streams with calculations that should be based on the entire biomass that enters the biorefinery.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The carbohydrate pulps, for instance, perform very well as a substrate for the separate enzymatic hydrolysis and fermentation (SHF) with production of bioethanol in several publications already, ,, while also being more prone to saccharification compared to pulp from a classic organosolv pretreatment . However, the field of organosolv research is advancing and shows progress to improve both the quality of the lignin products and the pulp’s susceptibility to enzymatic hydrolysis. , Negative effects of the pulp with residual lignin on the subsequent biochemical conversion of the RCF pulp, including bioethanol production with Saccharomyces cerevisiae, are currently debated, for example, questioning the necessity of substantial additional washing steps or not of the resulting RCF pulps to achieve high bioethanol yields. Despite requiring more exploration, the observed discrepancies are most likely caused by process parameters such as feedstock type, solvent composition, process conditions, and catalyst type that impact the pulp properties and subsequently also affect both the saccharification and fermentation.…”

Section: Introductionmentioning

confidence: 99%

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Uncovering Challenges for Complete Carbohydrate to Bioethanol Utilization in a Reductive Catalytic Fractionation Biorefinery

Nicolaï,

Arts,

Calderon-Ardila

et al. 2024

ACS Sustainable Chem. Eng.

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The reductive catalytic fractionation (RCF) biorefinery, developed for high-quality lignin oil extraction from lignocellulose biomass, concurrently produces a (hemi)cellulose pulp suitable for bioethanol production. Depending on the RCF severity and delignification, 5 to 25% of the biomass’ carbohydrates are solubilized, ending up in a distinct water fraction. With the premise of full biomass exploitation, while minimizing waste and the processing costs, this work studies the integration of both pulp and water fractions from varied RCF processing parameters into separate hydrolysis and fermentation (SHF) using birch wood and a xylose-utilizing Saccharomyces cerevisiae strain. Besides advancing water fraction characterization revealing certain (reduced) sugars (oligomers), methyl sugars, and shorter polyols, efficient saccharification of the RCF pulps, up to 98% sugar yield, is observed. With high delignification and carbohydrate solubilization in the RCF, a significant 6.2% ethanol titer increase can be achieved by addition of the water fraction to the SHF. We identify both carbohydrate polymers and α/β-methyl carbohydrates in the water fraction as a carbon source for additional bioethanol production. Introducing water fractions from alternative RCF conditions results in similar or lower ethanol yields, influencing both saccharification and yeast’s xylose utilization. From the perspective of the entire, raw biomass, the maximum carbohydrate to bioethanol utilization is achieved with specific RCF parameters that focus on sufficient delignification and high carbohydrate retention, concurrently obtaining water fractions with low carbohydrate content that is better not used for bioethanol production, overall yielding 79% sugar and 59% bioethanol, of their theoretical maximum, comparable to the reported yields for established second-generation carbohydrate-centered biorefineries using hardwood.

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Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Uncovering Challenges for Complete Carbohydrate to Bioethanol Utilization in a Reductive Catalytic Fractionation Biorefinery

Nicolaï,

Arts,

Calderon-Ardila

et al. 2024

ACS Sustainable Chem. Eng.

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“…After 120 h of semi-simultaneous saccharification and fermentation (S-SSF) by S. cerevisiae GSE16-T18-HAA1*, an ethanol titer of 36 g/L (73% of the theoretical yield) was obtained. In another work, Wu et al revealed that the residual RCF oil remaining on the surface of poplar pulps leaded to the severe inhibition of microorganisms, and an ethanol yield of 0.45 g/g (monomeric sugars in hydrolysate) with 17.77 g/L of ethanol can be achieved under separate hydrolysis and fermentation (SHF) in batch mode [ 31 ].…”

Section: Introductionmentioning

confidence: 99%

Sequential catalytic lignin valorization and bioethanol production: an integrated biorefinery strategy

Wu,

Su,

Liao

et al. 2024

Biotechnol Biofuels

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Background The effective valorization of lignin and carbohydrates in lignocellulose matrix under the concept of biorefinery is a primary strategy to produce sustainable chemicals and fuels. Based on the reductive catalytic fractionation (RCF), lignin in lignocelluloses can be depolymerized into viscous oils, while the highly delignified pulps with high polysaccharides retention can be transformed into various chemicals. Results A biorefinery paradigm for sequentially valorization of the main components in poplar sawdust was constructed. In this process, the well-defined low-molecular-weight phenols and bioethanol were co-generated by tandem chemo-catalysis in the RCF stage and bio-catalysis in fermentation stage. In the RCF stage, hydrogen transfer reactions were conducted in one-pot process using Raney Ni as catalyst, while the isopropanol (2-PrOH) in the initial liquor was served as a hydrogen donor and the solvent for lignin dissolution. Results indicated the proportion of the 2-PrOH in the initial liquor of RCF influenced the chemical constitution and yield of the lignin oil, which also affected the characteristics of the pulps and the following bioethanol production. A 67.48 ± 0.44% delignification with 20.65 ± 0.31% of monolignols yield were realized when the 2-PrOH:H2O ratio in initial liquor was 7:3 (6.67 wt% of the catalyst loading, 200 °C for 3 h). The RCF pulp had higher carbohydrates retention (57.96 ± 2.78 wt%), which was converted to 21.61 ± 0.62 g/L of bioethanol with a yield of 0.429 ± 0.010 g/g in fermentation using an engineered S. cerevisiae strain. Based on the mass balance analysis, 104.4 g of ethanol and 206.5 g of lignin oil can be produced from 1000 g of the raw poplar sawdust. Conclusions The main chemical components in poplar sawdust can be effectively transformed into lignin oil and bioethanol. The attractive results from the biorefinery process exhibit great promise for the production of valuable biofuels and chemicals from abundant lignocellulosic materials.

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“…[3] Therefore, the properly transformation of lignin compounds into valuable chemicals is emerged as an appealing approach to be investigated. [4,5] Among the lignin valorization products, vanillin has a broad application in food, pharmaceutical, nutraceutical, and cosmetic. [6] Traditionally, vanillin is synthesized by glyoxylic and nitrose methods from guaiacol in industry.…”

Section: Introductionmentioning

confidence: 99%

Nitrogen‐doped Titanium Dioxide for Enhanced Photocatalytic Oxidation of Vanillyl Alcohol into Vanillin

et al. 2023

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Photocatalysis transformation of renewable biomass-derived building blocks into value-added chemicals is an attractive strategy in response to the environmental issues caused by the use of unsustainable petrol-chemical routes. On this basis, photocatalytic selective oxidation of reduced monolignols into aldehydes has emerged as a hotspot to be investigated. Herein, using ammonia solution as nitrogen source, NÀ TiO 2 photocatalysts were prepared through a simple pyrolysis process. Under visible-light irradiation, the NÀ TiO 2 photocatalysts were applied for selective oxidation of vanillyl alcohol into vanillin in acetonitrile. Results suggested that after doping nitrogen into the basic TiO 2 , the NÀ TiO 2 photocatalysts exhibited a narrow band-gap that could broaden the light absorption range, inhibit the recombination of photogenerated carriers, and enhance the affinity to the substrate molecules. Consequently, the photocatalytic performances of the vanillyl alcohol can be extensively improved by the NÀ TiO 2 (N-400) photocatalyst. A selectivity of 60.37 % of vanillin and a conversion of 60.84 % of vanillyl alcohol can be realized under the optimized conditions. The mechanism for the improved photocatalysis performances of vanillyl alcohol by NÀ TiO 2 was further proposed by combining the experimental and simulated results, which inferred that h + was the decisive active species for the effective oxidation of vanillyl alcohol. The NÀ doped TiO 2 photocatalysts are also adequate to selective oxidation of other renewable bio-alcohols into aldehydes.

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Inhibitions of microbial fermentation by residual reductive lignin oil: Concerns on the bioconversion of reductive catalytic fractionated carbohydrate pulp

Cited by 18 publications

References 74 publications

Uncovering Challenges for Complete Carbohydrate to Bioethanol Utilization in a Reductive Catalytic Fractionation Biorefinery

Uncovering Challenges for Complete Carbohydrate to Bioethanol Utilization in a Reductive Catalytic Fractionation Biorefinery

Sequential catalytic lignin valorization and bioethanol production: an integrated biorefinery strategy

Nitrogen‐doped Titanium Dioxide for Enhanced Photocatalytic Oxidation of Vanillyl Alcohol into Vanillin

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