Display omitted
•The preparation process of hydrophilic-hydrophobic PAM/PS IPNs was optimized.•PAM/PS IPNs was used to remove fermentation inhibitors from SCBH.•PAM/PS IPNs had excellent adsorption ...performance towards fermentation inhibitors.•PAM/PS IPNs can be regenerated easily and reused stably.
Economical removal of fermentation inhibitors from lignocellulosic hydrolysate plays a considerable role in bioconversion of lignocellulose biomass. In this work, the textural properties of polyacrylamide/polystyrene interpenetrating polymer networks (PAM/PS IPNs) on adsorption of fermentation inhibitors from sugarcane bagasse hydrolysate (SCBH) were investigated for the first time. The results showed that, the specific surface area, pore diameter and surface polarity had important influence on its adsorption performance towards sugars, organic acids, furans and acid-soluble lignin. The PAM/PS IPNs under the optimal copolymerization situation achieved the high selectivity coefficients of 4.07, 14.9, 21.2 and 25.8 with respective to levulinic acid, furfural, hydroxymethylfurfural (HMF) and acid-soluble lignin, and had a low total sugar loss of 2.09%. Overall, this research puts forward a design and synthetic strategy for adsorbent to remove fermentation inhibitors from lignocellulosic hydrolysate.
•A new route for hemicellulose derived aviation fuel production was proposed.•This route follows hydrolysis/dehydration, hydrogenation, coupling and HDO steps.•The effective hydrogenation and ...hydrodeoxygenation catalysts were prepared.•The high yield of C8C15 alkanes and catalytic stability were obtained.
This paper presents a new route for biomass derived aviation fuel synthesis by catalytic conversion in aqueous phase. Furfural with the yield of 71% was produced by acid hydrolysis of raw corncob, and hydrogenated to 2-methylfuran with obtaining the yield of 89% over Raney Ni catalyst, both of which were implemented under mild reaction conditions. The hydroxyalkylation/alkylation condensation of 2-methylfuran and furfural to C15 intermediate was conducted by using organic and inorganic acid as the catalyst under the reaction condition of 328K and atmospheric pressure. The maximal 95% of the C15 intermediate was gained when using sulfuric acid as the catalyst. 83% of liquid alkanes (C8C15) yield and more than 90% of C14/C15 selectivity were produced by hydrodeoxygenation of the C15 intermediate over 10wt%Ni/ZrO2–SiO2 catalyst. During the hydrodeoxygenation process, the catalyst showed excellent stability depended on the 110h of time-on-stream test, due to its significantly decreased carbon deposition.
Xylitol is a building block for a variety of chemical commodities, besides being widely used as a sugar substitute in the food and pharmaceutical industries. The aim of this work was to develop a ...microbial process for xylitol production using sugarcane bagasse hydrolysate as substrate. In this context, 218 non‐Saccharomyces yeast strains were screened by growth on steam‐exploded sugarcane bagasse hydrolysate containing a high concentration of acetic acid (8.0 g/L). Seven new Candida tropicalis strains were selected and identified, and their ability to produce xylitol on hydrolysate at low pH (4.6) under aerobic conditions was evaluated. The most efficient strain, designated C. tropicalis JA2, was capable of producing xylitol with a yield of 0.47 g/g of consumed xylose. To improve xylitol production by C. tropicalis JA2, a series of experimental procedures were employed to optimize pH and temperature conditions, as well as nutrient source, and initial xylose and inoculum concentrations. C. tropicalis JA2 was able to produce 109.5 g/L of xylitol with a yield of 0.86 g/g of consumed xylose, and with a productivity of 2.81 g·L·h, on sugarcane bagasse hydrolysate containing 8.0 g/L acetic acid and177 g/L xylose, supplemented with 2.0 g/L yeast nitrogen base and 4.0 g/L urea. Thus, it was possible to identify a new C. tropicalis strain and to optimize the xylitol production process using sugarcane bagasse hydrolysate as a substrate. The xylitol yield on biomass hydrolysate containing a high concentration of acetic acidobtained in here is among the best reported in the literature.
Interest in the production of renewable chemicals from biomass has increased in the past years. Among these chemicals, carboxylic acids represent a significant part of the most desirable bio-based ...products. Xylonic acid is a five-carbon sugar-acid obtained from xylose oxidation that can be used in several industrial applications, including food, pharmaceutical, and construction industries. So far, the production of xylonic acid has not yet been available at an industrial scale; however, several microbial bio-based production processes are under development. This review summarizes the recent advances in pathway characterization, genetic engineering, and fermentative strategies to improve xylonic acid production by microorganisms from xylose or lignocellulosic hydrolysates. In addition, the strengths of the available microbial strains and processes and the major requirements for achieving biotechnological production of xylonic acid at a commercial scale are discussed. Efficient native and engineered microbial strains have been reported. Xylonic acid titers as high as 586 and 171 g L
−1
were obtained from bacterial and yeast strains, respectively, in a laboratory medium. Furthermore, relevant academic and industrial players associated with xylonic acid production will be presented.
Display omitted
•Acidic biomass hydrolysate conversion over Aqueous catalytic system of Ru/C.•61.9% C5/C6 alkane yielded from 20wt% sorbitol solution.•Cassava and corncob hydrolysate were tested with ...C5/C6 yield of 38.8% and 44.1%, respectively.
In this work, a dual-bed aqueous catalysis system with Ru/C as catalyst was proposed for the liquid alkane (pentane/hexane: C5/C6) production from acid biomass hydrolysate. The low temperature (413K) hydrogenation of biomass-derived carbohydrates into polyols was carried out in the first fixed-bed. The high temperature (523K) hydrodeoxygenation (HDO) of polyols into alkanes was carried out in the down-stream bed. To screen the optimal reaction conditions, glucose and sorbitol were chosen for model tests. Whereby, reactor types, solution pH value, mineral acid, reaction temperature, pressure and sorbitol concentrations were studied. A maximum C5/C6 alkane yield of 61.9% was achieved from 20wt% sorbitol solution (pH=1.5) under 523K and 4MPa H2 pressure in the fixed-bed reactor. For cassava and corncob hydrolysate, C5/C6 alkane yield of 38.8% and 44.1% were obtained, respectively.
Oleaginous yeasts are promising microbial platforms for sustainable, bio-based production of biofuels and oleochemical building blocks. Bio-based residues provide sustainable and cost-effective ...carbon sources for fermentative yeast oil production without land-use change. Considering the regional abundancy of different waste streams, we chose complex biomass residue streams of marine origin; macroalgae hydrolysate, and terrestrial origin; wheat straw hydrolysate in the presence, and absence of corn steep liquor as a complex nitrogen source. We investigated the biomass and lipid yields of an array of well-described oleaginous yeasts; R. glutinis, T. asahii, R. mucilaginosa, R. toruloides, C. oleaginosus growing on these hydrolysates. Furthermore, their sugar utilization, fatty acid profile, and inhibitory effect of the hydrolysates on yeast growth were compared. For correlative reference, we initially performed comparative growth experiments for the strains on individual monomeric sugars separately. Each of these monomeric sugars was a dominant carbon source in the complex biomass hydrolysates evaluated in this study. In addition, we evaluated N-acetylglucosamine, the monomeric building block of chitin, as a low-cost nitrogen and carbon source in yeast fermentation.
C. oleaginosus provided the highest biomass and lipid yields. In the wheat straw and brown algae hydrolysates, this yeast strain gained 7.5 g/L and 3.8 g/L lipids, respectively. Cultivation in algae hydrolysate resulted in a higher level of unsaturated fatty acids in the lipids accumulated by all yeast strains. R. toruloides and C. oleaginosus were able to effectively co-utilize mannitol, glucose, and xylose. Growth rates on wheat straw hydrolysate were enhanced in presence of corn steep liquor.
Among the yeast strains investigated in this study, C. oleaginosus proved to be the most versatile strain in terms of substrate utilization, productivity, and tolerance in the complex media. Various fatty acid profiles obtained on each substrate encourage the manipulation of culture conditions to achieve the desired fatty acid composition for each application. This could be accomplished by combining the element of carbon source with other formerly studied factors such as temperature and oxygen. Moreover, corn steep liquor showed promise for enhancement of growth in the oleaginous strains provided that carbon substrate is available.
The consumption of fossil fuels has resulted in severe environmental consequences, including greenhouse gas emissions and climate change. Therefore, transitioning to alternative energy sources, such ...as cellulosic ethanol, is a promising strategy for reducing environmental impacts and promoting sustainable low-carbon energy. Vietnamosasa pusilla, an invasive weed, has been recognized as a high potential feedstock for sugar-based biorefineries due to its high total carbohydrate content, including glucan (48.1 ± 0.3%) and xylan (19.2 ± 0.4%). This study aimed to examine the impact of NaOH pretreatment-assisted autoclaving on V. pusilla feedstock. The V. pusilla enzymatic hydrolysate was used as a substrate for bioethanol and xylitol synthesis. After treating the feedstock with varying concentrations of NaOH at different temperatures, the glucose and xylose recovery yields were substantially higher than those of the untreated material. The hydrolysate generated by enzymatic hydrolysis was fermented into bioethanol using Saccharomyces cerevisiae TISTR 5339. The liquid byproduct of ethanol production was utilized by Candida tropicalis TISTR 5171 to generate xylitol. The results of this study indicate that the six- and five-carbon sugars of V. pusilla biomass have great potential for the production of two value-added products (bioethanol and xylitol).
has been successfully employed for the industrial production of amino acids and other bioproducts, partially due to its native ability to utilize a wide range of carbon substrates. We demonstrated
as ...an efficient microbial host for utilizing diverse carbon substrates present in biomass hydrolysates, such as glucose, arabinose, and xylose, in addition to its natural ability to assimilate lignin-derived aromatics. As a case study to demonstrate its bioproduction capabilities, L-lactate was chosen as the primary fermentation end product along with acetate and succinate.
was found to grow well in different aromatics (benzoic acid, cinnamic acid, vanillic acid, and p-coumaric acid) up to a concentration of 40 mM. Besides,
C-fingerprinting confirmed that carbon from aromatics enter the primary metabolism via TCA cycle confirming the presence of β-ketoadipate pathway in
.
C-fingerprinting in the presence of both glucose and aromatics also revealed coumarate to be the most preferred aromatic by
contributing 74 and 59% of its carbon for the synthesis of glutamate and aspartate respectively.
C-fingerprinting also confirmed the activity of ortho-cleavage pathway, anaplerotic pathway, and cataplerotic pathways. Finally, the engineered
strain grew well in biomass hydrolysate containing pentose and hexose sugars and produced L-lactate at a concentration of 47.9 g/L and a yield of 0.639 g/g from sugars with simultaneous utilization of aromatics. Succinate and acetate co-products were produced at concentrations of 8.9 g/L and 3.2 g/L, respectively. Our findings open the door to valorize all the major carbon components of biomass hydrolysate by using
as a microbial host for biomanufacturing.
•Hardwood pre-hydrolysates from dissolving pulp mill were used for ABE fermentation.•Flocculation was the most efficient method for inhibitors removal.•Detoxification increased the phenolics ...inhibitory level on ABE production up to 1.1g/L.
The feasibility of using hardwood hemicellulosic pre-hydrolysate recovered from a dissolving pulping process for Acetone–Butanol–Ethanol (ABE) fermentation has been investigated. Dilutions and detoxification methods based on flocculation and nanofiltration were tested to determine the inhibitory concentration of phenolic compounds and to evaluate the efficiency of inhibitors removal on fermentation. Flocculation carried out with ferric sulfate was the most effective method for removal of phenolics (56%) and acetic acid (80%). The impact on fermentation was significant, with an ABE production of 6.40g/L and 4.25g/L when using flocculation or combined nanofiltration/flocculation respectively, as compared to a non-significant production for the untreated hydrolysate. By decreasing the toxicity effect of inhibitors, this study reports for the first time that the use of these techniques is efficient to increase the inhibitory concentration threshold of phenols, from 0.3g/L in untreated hydrolysate, to 1.1g/L in flocculated and in nanofiltrated and flocculated hydrolysates.
PDF
