Pyrolysis Byproducts as Feedstocks for Fermentative Biofuel Production: An Evaluation of Inhibitory Compounds through a Synthetic Aqueous Phase

This study focuses on the valorization of the organic fraction of municipal solid waste (biopulp) by hydrothermal liquefaction. Thereby, homogeneous alkali catalysts (KOH, NaOH, K2CO3, and Na2CO3) and a residual aqueous phase recirculation methodology were mutually employed to enhance the bio-crude yield and energy efficiency of a sub-critical hydrothermal conversion (350 °C, 15–20 Mpa, 15 min). Interestingly, single recirculation of the concentrated aqueous phase positively increased the bio-crude yield in all cases, while the higher heating value (HHV) of the bio-crudes slightly dropped. Compared to the non-catalytic experiment, K2CO3 and Na2CO3 effectively increased the bio-crude yield by 14 and 7.3%, respectively. However, KOH and NaOH showed a negative variation in the bio-crude yield. The highest bio-crude yield (37.5 wt.%) and energy recovery (ER) (59.4%) were achieved when K2CO3 and concentrated aqueous phase recirculation were simultaneously applied to the process. The inorganics distribution results obtained by ICP reveal the tendency of the alkali elements to settle into the aqueous phase, which, if recovered, can potentially boost the circularity of the HTL process. Therefore, wise selection of the alkali catalyst along with aqueous phase recirculation assists hydrothermal liquefaction in green biofuel production and environmentally friendly valorization of biopulp.

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Anaerobic conversion of the hydrothermal liquefaction aqueous phase: fate of organics and intensification with granule activated carbon/ozone pretreatment

Green Chemistry ◽

10.1039/c8gc02907e ◽

2019 ◽

Vol 21 (6) ◽

pp. 1305-1318 ◽

Cited By ~ 20

Author(s):

Buchun Si ◽

Libin Yang ◽

Xuefei Zhou ◽

Jamison Watson ◽

Giovana Tommaso ◽

...

Keyword(s):

Activated Carbon ◽

Aqueous Phase ◽

Hydrothermal Liquefaction ◽

Biofuel Production ◽

Wet Biomass ◽

Ozone Pretreatment ◽

Anaerobic Conversion

Hydrothermal liquefaction (HTL) is considered to be a promising route for biofuel production from wet biomass.

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Suppressing inhibitory compounds by nanomaterials for highly efficient biofuel production: A review

Fuel ◽

10.1016/j.fuel.2021.122934 ◽

2022 ◽

Vol 312 ◽

pp. 122934

Author(s):

Abhinay Thakur ◽

Ashish Kumar ◽

Savas Kaya ◽

Dai-Viet N. Vo ◽

Ajit Sharma

Keyword(s):

Biofuel Production ◽

Highly Efficient ◽

Inhibitory Compounds

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Bioprospecting of microbial strains for biofuel production: metabolic engineering, applications, and challenges

Biotechnology for Biofuels ◽

10.1186/s13068-020-01853-2 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Mobolaji Felicia Adegboye ◽

Omena Bernard Ojuederie ◽

Paola M. Talia ◽

Olubukola Oluranti Babalola

Keyword(s):

Metabolic Engineering ◽

Lignocellulosic Biomass ◽

Metabolic Pathways ◽

Biofuel Production ◽

Advanced Technology ◽

Biological Degradation ◽

Microbial Cell Factories ◽

Cell Factories ◽

Inhibitory Compounds ◽

Wide Range

AbstractThe issues of global warming, coupled with fossil fuel depletion, have undoubtedly led to renewed interest in other sources of commercial fuels. The search for renewable fuels has motivated research into the biological degradation of lignocellulosic biomass feedstock to produce biofuels such as bioethanol, biodiesel, and biohydrogen. The model strain for biofuel production needs the capability to utilize a high amount of substrate, transportation of sugar through fast and deregulated pathways, ability to tolerate inhibitory compounds and end products, and increased metabolic fluxes to produce an improved fermentation product. Engineering microbes might be a great approach to produce biofuel from lignocellulosic biomass by exploiting metabolic pathways economically. Metabolic engineering is an advanced technology for the construction of highly effective microbial cell factories and a key component for the next-generation bioeconomy. It has been extensively used to redirect the biosynthetic pathway to produce desired products in several native or engineered hosts. A wide range of novel compounds has been manufactured through engineering metabolic pathways or endogenous metabolism optimizations by metabolic engineers. This review is focused on the potential utilization of engineered strains to produce biofuel and gives prospects for improvement in metabolic engineering for new strain development using advanced technologies.

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Influence of Inhibitory Compounds on Biofuel Production from Oxalate-Rich Rhubarb Leaf Hydrolysates Using Thermoanaerobacter thermohydrosulfuricus Strain AK91

Fuels ◽

10.3390/fuels2010005 ◽

2021 ◽

Vol 2 (1) ◽

pp. 71-86

Author(s):

Johann Orlygsson ◽

Sean Michael Scully

Keyword(s):

Carboxylic Acids ◽

Batch Culture ◽

Anaerobic Bacteria ◽

Culture Conditions ◽

Biofuel Production ◽

Biohydrogen Production ◽

Primary Alcohols ◽

Inhibitory Compounds ◽

High Concentrations ◽

Specific Culture

The present investigation is on bioethanol and biohydrogen production from oxalate-rich rhubarb leaves which are an underutilized residue of rhubarb cultivation. Rhubarb leaves can be the feedstock for bioethanol and biohydrogen production using thermophilic, anaerobic bacteria. The fermentation of second-generation biomass to biofuels by Thermoanaerobacter has already been reported as well as their high ethanol and hydrogen yields although rhubarb biomass has not been examined for this purpose. Thermoanaerobacter thermohydrosulfuricus strain AK91 was characterized (temperature and pH optima, substrate utilization spectrum) which demonstrates that the strain can utilize most carbohydrates found in lignocellulosic biomass. Additionally, the influence of specific culture conditions, namely the partial pressure of hydrogen and initial glucose concentration, were investigated in batch culture and reveals that the strain is inhibited. Additionally, batch experiments containing common inhibitory compounds, namely carboxylic acids and aldehydes, some of which are present in high concentrations in rhubarb. Strain AK91 is not affected by alkanoic carboxylic acids and oxalate up to at least 100 mM although the strain was inhibited by 40 mM of malate. Interestingly, strain AK91 demonstrated the ability to reduce alkanoic carboxylic acids to their primary alcohols; more detailed studies with propionate as a model compound demonstrated that AK91’s growth is not severally impacted by high propionate loadings although 1-propanol titers did not exceed 8.5 mM. Additionally, ethanol and hydrogen production from grass and rhubarb leaf hydrolysates was investigated in batch culture for which AK91 produced 7.0 and 6.3 mM g−1, respectively.

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Harnessing Genetic Diversity in Saccharomyces cerevisiae for Fermentation of Xylose in Hydrolysates of Alkaline Hydrogen Peroxide-Pretreated Biomass

Applied and Environmental Microbiology ◽

10.1128/aem.01885-13 ◽

2013 ◽

Vol 80 (2) ◽

pp. 540-554 ◽

Cited By ~ 36

Author(s):

Trey K. Sato ◽

Tongjun Liu ◽

Lucas S. Parreiras ◽

Daniel L. Williams ◽

Dana J. Wohlbach ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Hydrogen Peroxide ◽

Rapid Evolution ◽

Biofuel Production ◽

Ecological Niches ◽

Alkaline Hydrogen Peroxide ◽

Xylose Metabolism ◽

Content Type ◽

Inhibitory Compounds ◽

Lignocellulosic Biofuel

ABSTRACTThe fermentation of lignocellulose-derived sugars, particularly xylose, into ethanol by the yeastSaccharomyces cerevisiaeis known to be inhibited by compounds produced during feedstock pretreatment. We devised a strategy that combined chemical profiling of pretreated feedstocks, high-throughput phenotyping of genetically diverseS. cerevisiaestrains isolated from a range of ecological niches, and directed engineering and evolution against identified inhibitors to produce strains with improved fermentation properties. We identified and quantified for the first time the major inhibitory compounds in alkaline hydrogen peroxide (AHP)-pretreated lignocellulosic hydrolysates, including Na+, acetate, andp-coumaric (pCA) and ferulic (FA) acids. By phenotyping these yeast strains for their abilities to grow in the presence of these AHP inhibitors, one heterozygous diploid strain tolerant to all four inhibitors was selected, engineered for xylose metabolism, and then allowed to evolve on xylose with increasing amounts ofpCA and FA. After only 149 generations, one evolved isolate, GLBRCY87, exhibited faster xylose uptake rates in both laboratory media and AHP switchgrass hydrolysate than its ancestral GLBRCY73 strain and completely converted 115 g/liter of total sugars in undetoxified AHP hydrolysate into more than 40 g/liter ethanol. Strikingly, genome sequencing revealed that during the evolution from GLBRCY73, the GLBRCY87 strain acquired the conversion of heterozygous to homozygous alleles in chromosome VII and amplification of chromosome XIV. Our approach highlights that simultaneous selection on xylose andpCA or FA with a wildS. cerevisiaestrain containing inherent tolerance to AHP pretreatment inhibitors has potential for rapid evolution of robust properties in lignocellulosic biofuel production.

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AGEs Formation Inhibitory Compounds of Euphorbia pekinensis and Their Effects on Vessel Dilation in Larval Zebrafish In Vivo

10.1055/s-0037-1608087 ◽

2017 ◽

Author(s):

S Lee Ik ◽

S Kim Jin

Keyword(s):

Larval Zebrafish ◽

Inhibitory Compounds

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Early Platelet-Collagen Interactions in Whole Blood and Their Modifications by Aspirin and Dipyridamole Evaluated by a New Method (Basic Wave)

Thrombosis and Haemostasis ◽

10.1055/s-0038-1660136 ◽

1985 ◽

Vol 54 (04) ◽

pp. 799-803 ◽

Cited By ~ 14

Author(s):

José Luís Pérez-Requejo ◽

Justo Aznar ◽

M Teresa Santos ◽

Juana Vallés

Keyword(s):

Whole Blood ◽

Ex Vivo ◽

Platelet Rich Plasma ◽

White Blood Cells ◽

Reversible Aggregation ◽

Inhibitory Compounds ◽

Rapid Generation ◽

Stimulation Of ◽

Collagen Stimulation

SummaryIt is shown that the supernatant of unstirred whole blood at 37° C, stimulated by 1 μg/ml of collagen for 10 sec, produces a rapid generation of pro and antiaggregatory compounds with a final proaggregatory activity which can be detected for more than 60 min on a platelet rich plasma (PRP) by turbidometric aggregometry. A reversible aggregation wave that we have called BASIC wave (for Blood Aggregation Stimulatory and Inhibitory Compounds) is recorded. The collagen stimulation of unstirred PRP produces a similar but smaller BASIC wave. BASIC’s intensity increases if erythrocytes are added to PRP but decreases if white blood cells are added instead. Aspirin abolishes “ex vivo” the ability of whole blood and PRP to generate BASIC waves and dipyridamole “in vitro” significantly reduces BASIC’s intensity in whole blood in every tested sample, but shows little effect in PRP.

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