Commodity Chemicals Research Articles

Horizontal metaproteomics and CAZymes analysis oflignocellulolytic microbial consortia selectively enriched from cow rumen and termitegut

Selectively enriched microbial consortia are potentially useful for theconversion of lignocellulose (LC) into biofuels and commodity chemicals. Consortiaare also of interest to elucidate the roles of individual microorganisms and thedynamics of enzymes involved in LC deconstruction. Using metaproteomics, 16 S rRNAgene amplicon sequencing and multivariate discriminant analysis, we revealed thetemporal dynamics of microbial species and their proteins during anaerobicconversion of LC by microbial consortia derived from cow rumen (RWS) and termite gut(TWS) microbiomes. Bacteroidetes (Bacteroidota), Firmicutes (Bacillota) andProteobacteria (Pseudomonadota) phyla were dominant, irrespective the inoculumorigin, displaying functional complementarities. We identified a large variety ofcarbohydrate-active enzymes, distributed in 94 CAZy families, involved in biomassdeconstruction. Additionally, proteins involved in short chain fatty acidsbiosynthesis were detected. Multivariate analysis clearly differentiates RWS and TWSmetaproteomes, with differences originating in the initial inoculates. Furthersupervised discriminant analysis of the temporal succession of CAZymes revealed thatboth consortia consume easily accessible oligosaccharides during the early stage ofincubation, degrading more complex hemicellulose and cellulose fractions at laterstages, an action that pursues throughout the incubation period. Our results providenew insights regarding the functional roles and complementarities existing inlignocellulolytic consortia and highlight their potential for biorefineryapplications.

Sustainable Sulfonic Acid Functionalized Tubular Shape Mesoporous Silica as a Heterogeneous Catalyst for Selective Unsymmetrical Friedel-Crafts Alkylation in One Pot.

The development of general and more sustainable heterogeneous catalytic processes for Friedel-Crafts (FC) alkylation reactions is a key objective of interest for the synthesis of pharmaceuticals and commodity chemicals. Sustainable heterogeneous catalysis for the typical FC alkylation of an easily accessible carbonyl electrophile and arenes or with two different arene nucleophiles in one-pot is a prime challenge. Herein, we present a resolution to these issues through the design and utilization of a mesoporous silica catalyst that has been functionalized with sulfonic acid. For the synthesis of sulfonic acid-functionalized mesoporous silica (MSN-SO3H), thiol-functionalized mesoporous silica was first synthesized by the co-condensation method, followed by oxidation of the thiol functionality to the sulfonic acid group. Sulfonation of mesoporous silica was confirmed by 13C CP MAS NMR spectroscopy. Further, the devised heterogeneous catalysis using MSN-SO3H has been successfully employed in the construction of diverse polyalkanes including various bioactive molecules, viz arundine, tatarinoid-C, and late-stage functionalization of natural products like menthol and Eugenol. Further, we have utilized this sustainable technique to facilitate the formation of unsymmetrical C-S bonds in a one-pot fashion. In addition, the catalyst was successfully recovered and recycled for eight cycles, demonstrating the high sustainability and cost-effectiveness of this protocol for both academic and industrial applications.

Leveraging the Proximity and Distribution of Cu−Cs Sites for Direct Conversion of Methanol to Esters/Aldehydes

AbstractMethanol serves as a versatile building‐block for various commodity chemicals, and the development of industrially promising strategies for its conversion remains the ultimate goal in methanol chemistry. In this study, we design a dual Cu−Cs catalytic system that enables a one‐step direct conversion of methanol and methyl acetate/ethanol into high value‐added esters/aldehydes, with customized chain length and saturation by leveraging the proximity and distribution of Cu−Cs sites. Cu−Cs at a millimeter‐scale intimacy triggers methanol dehydrogenation and condensation, involving proton transfer, aldol formation, and aldol condensation, to obtain unsaturated esters and aldehydes with selectivities of 76.3 % and 31.1 %, respectively. Cu−Cs at a micrometer‐scale intimacy significantly promotes mass transfer of intermediates across catalyst interfaces and their subsequent hydrogenation to saturated esters and aldehydes with selectivities of 67.6 % and 93.1 %, respectively. Conversely, Cu−Cs at a nanometer‐scale intimacy alters reaction pathway with a similar energy barrier for the rate‐determining step, but blocks the acidic‐basic sites and diverts the reaction to byproducts. More importantly, an unprecedented quadruple tandem catalytic production of methyl methacrylate (MMA) is achieved by further tailoring Cu and Cs distribution across the reaction bed in the configuration of Cu−Cs||Cs, outperforming the existing industrial processes and saving at least 15 % of production costs.

Leveraging the Proximity and Distribution of Cu-Cs Sites for Direct Conversion of Methanol to Esters/Aldehydes.

Methanol serves as a versatile building-block for various commodity chemicals, and the development of industrially promising strategies for its conversion remains the ultimate goal in methanol chemistry. In this study, we design a dual Cu-Cs catalytic system that enables a one-step direct conversion of methanol and methyl acetate/ethanol into high value-added esters/aldehydes, with customized chain length and saturation by leveraging the proximity and distribution of Cu-Cs sites. Cu-Cs at a millimeter-scale intimacy triggers methanol dehydrogenation and condensation, involving proton transfer, aldol formation, and aldol condensation, to obtain unsaturated esters and aldehydes with selectivities of 76.3 % and 31.1 %, respectively. Cu-Cs at a micrometer-scale intimacy significantly promotes mass transfer of intermediates across catalyst interfaces and their subsequent hydrogenation to saturated esters and aldehydes with selectivities of 67.6 % and 93.1 %, respectively. Conversely, Cu-Cs at a nanometer-scale intimacy alters reaction pathway with a similar energy barrier for the rate-determining step, but blocks the acidic-basic sites and diverts the reaction to byproducts. More importantly, an unprecedented quadruple tandem catalytic production of methyl methacrylate (MMA) is achieved by further tailoring Cu and Cs distribution across the reaction bed in the configuration of Cu-Cs||Cs, outperforming the existing industrial processes and saving at least 15 % of production costs.

Production of carotenoids from aromatics and pretreated lignocellulosic biomass by Novosphingobium aromaticivorans.

There is economic and environmental interest in generating commodity chemicals from renewable resources, such as lignocellulosic biomass, that can substitute for chemicals derived from fossil fuels. The bacterium Novosphingobium aromaticivorans is a promising microbial platform for producing commodity chemicals from lignocellulosic biomass because it can produce these from compounds in pretreated lignocellulosic biomass, which many industrial microbial catalysts cannot metabolize. Here, we show that N. aromaticivorans can be engineered to produce several valuable carotenoids. We also show that engineered N. aromaticivorans strains can produce these lipophilic chemicals concurrently with the extracellular commodity chemical 2-pyrone-4,6-dicarboxylic acid when grown in a complex liquor obtained from alkaline pretreated lignocellulosic biomass. Concurrent microbial production of valuable intra- and extracellular products can increase the economic value generated from the conversion of lignocellulosic biomass-derived compounds into commodity chemicals and facilitate the separation of water- and membrane-soluble products.

Semiconductor nanosheets for electrocatalytic self-coupling of benzaldehyde to hydrobenzoin

The electrochemical reduction of biomass-derived feedstocks provides a sustainable platform for the synthesis of a wide range of chemical commodities and biofuels. Despite their interest, the optimization of reaction conditions, the screening of electrode materials, and the mechanistic understanding of these processes lag well behind other chemical routes. Here, we focus on the electrochemical self-coupling of benzaldehyde (BZH) to hydrobenzoin (HDB) using semiconductor electrocatalysts with nanosheet morphologies. By testing several semiconductor materials, a correlation is observed between their band gap and the electrochemical potential necessary to maximize selectivity towards HDB in alkaline medium, which we associate with the charge accumulation at the semiconductor surface. N-type CuInS2 provides the highest conversion rate at 0.3 mmol cm−2h−1 with a selectivity of 98.5 % at −1.3 V vs. Hg/HgO. Additional density functional theory calculations demonstrate a lower kinetic energy barrier at the CuInS2 surface compared with graphitic carbon, proving its catalytic role in the self-coupling reaction of BZH.

A Solar to Chemical Strategy: Green Hydrogen as a Means, Not an End.

Green hydrogen is the key to the chemical industry achieving net zero emissions. The chemical industry is responsible for almost 2% of all CO2 emissions, with half of it coming from the production of simple commodity chemicals, such as NH3, H2O2, methanol, and aniline. Despite electrolysis driven by renewable power sources emerging as the most promising way to supply all the green hydrogen required in the production chain of these chemicals, in this review, it is worth noting that the photocatalytic route may be underestimated and can hold a bright future for this topic. In fact, the production of H2 by photocatalysis still faces important challenges in terms of activity, engineering, and economic feasibility. However, photocatalytic systems can be tailored to directly convert sunlight and water (or other renewable proton sources) directly into chemicals, enabling a solar-to-chemical strategy. Here, a series of recent examples are presented, demonstrating that photocatalysis can be successfully employed to produce the most important commodity chemicals, especially on NH3, H2O2, and chemicals produced by reduction reactions. The replacement of fossil-derived H2 in the synthesis of these chemicals can be disruptive, essentially safeguarding the transition of the chemical industry to a low-carbon economy.

Structure-guided engineering of branched-chain α-keto acid decarboxylase for improved 1,2,4-butanetriol production by in vitro synthetic enzymatic biosystem

Efficient synthetic routes for biomanufacturing chemicals often require the overcoming of pathway bottlenecks by tailoring enzymes to improve the catalytic efficiency or even implement non-native activities. 1,2,4-butanetriol (BTO), a valuable commodity chemical, is currently biosynthesized from D-xylose via a four-enzyme reaction cascade, with the ThDP-dependent α-keto acid decarboxylase (KdcA) identified as the potential bottleneck. Here, to further enhance the catalytic activity of KdcA toward the non-native substrate α-keto-3-deoxy-xylonate (KDX), in silico screening and structure-guided evolution were performed. The best mutants, S286L/G402P and V461K, exhibited a 1.8- and 2.5-fold higher enzymatic activity in the conversion of KDX to 3,4-dihydroxybutanal when compared to KdcA, respectively. MD simulations revealed that the two sets of mutations reshaped the substrate binding pocket, thereby increasing the binding affinity for KDX and promoting interactions between KDX and cofactor ThDP. Then, when the V461K mutant instead of wild type KdcA was integrated into the enzyme cascade, a 1.9-fold increase in BTO titer was observed. After optimization of the reaction conditions, the enzyme cocktail contained V461K converted 60 g/L D-xylose to 22.1 g/L BTO with a yield of 52.1 %. This work illustrated that protein engineering is a powerful tool for modifying the output of metabolic pathway.

Engineering the synthetic β-alanine pathway in Komagataella phaffii for conversion of methanol into 3-hydroxypropionic acid

BackgroundMethanol is increasingly gaining attraction as renewable carbon source to produce specialty and commodity chemicals, as it can be generated from renewable sources such as carbon dioxide (CO2). In this context, native methylotrophs such as the yeast Komagataella phaffii (syn Pichia pastoris) are potentially attractive cell factories to produce a wide range of products from this highly reduced substrate. However, studies addressing the potential of this yeast to produce bulk chemicals from methanol are still scarce. 3-Hydroxypropionic acid (3-HP) is a platform chemical which can be converted into acrylic acid and other commodity chemicals and biopolymers. 3-HP can be naturally produced by several bacteria through different metabolic pathways.ResultsIn this study, production of 3-HP via the synthetic β-alanine pathway has been established in K. phaffii for the first time by expressing three heterologous genes, namely panD from Tribolium castaneum, yhxA from Bacillus cereus, and ydfG from Escherichia coli K-12. The expression of these key enzymes allowed a production of 1.0 g l−1 of 3-HP in small-scale cultivations using methanol as substrate. The addition of a second copy of the panD gene and selection of a weak promoter to drive expression of the ydfG gene in the PpCβ21 strain resulted in an additional increase in the final 3-HP titer (1.2 g l−1). The 3-HP-producing strains were further tested in fed-batch cultures. The best strain (PpCβ21) achieved a final 3-HP concentration of 21.4 g l−1 after 39 h of methanol feeding, a product yield of 0.15 g g−1, and a volumetric productivity of 0.48 g l−1 h−1. Further engineering of this strain aiming at increasing NADPH availability led to a 16% increase in the methanol consumption rate and 10% higher specific productivity compared to the reference strain PpCβ21.ConclusionsOur results show the potential of K. phaffii as platform cell factory to produce organic acids such as 3-HP from renewable one-carbon feedstocks, achieving the highest volumetric productivities reported so far for a 3-HP production process through the β-alanine pathway.

Concurrent electrocatalytic hydrogen evolution and polyethylene terephthalate plastics reforming by self-supported amorphous cobalt iron phosphide electrode

The electrocatalytic hydrogen evolution reaction (HER) coupled with oxidative transformation of plastics into commodity chemical is a promising tactic to relieve the energy shortage and white pollution problems via sustainable and profitable manner, which necessitates highly active bifunctional catalytic electrode and meticulous construction of electrolysis system. Herein, a self-supported amorphous cobalt iron phosphide onto nickel foam (NF) substrate, labeled as CoFe-P/NF, was prepared by electrodeposition, which served as bifunctional catalytic electrode for alkali hydrogen evolution reaction (HER) and selective electrooxidation of polyethylene terephthalate (PET) plastic hydrolysate toward formate. Benefiting from the abundant catalytic sites within amorphous structure, the interelement synergy and sufficient exposure of catalyst to electrolyte, the self-supported CoFe-P/NF electrode displayed low overpotential (η100 of 168 mV at current density of J = 100 mA cm−2), decent stability for HER and fine tolerance to PET monomers. The CoFe-P/NF electrode could also catalyze selective electrooxidation of ethylene glycol (EG) component in PET hydrolysate to formate with high productivity (0.1 mmol cm-2h−1) and faradaic efficiency (FE, 90 %) at 1.5 V. The PET hydrolysate electrolysis system based on CoFe-P/NF enabled coproduction of H2 and value added formate at lower voltage (1.52 V at J = 20 mA cm−2) and energy consumption (84 % at J = 200 mA cm−2) relative to water electrolysis. This work showcases the coproduction of H2 fuel and formate by electrolysis of PET hydrolysate via rational design of bifunctional catalytic electrode. We believe such type of versatile catalytic electrodes can find application scenarios in electrosynthesis of more commodity chemicals and energy devices beyond the case herein.

Recent Developments in Rongalite Chemistry: A Critical Review

AbstractRongalite whose chemical structure was discovered in 1905, is an inexpensive, easily assessable, and copious industrial product, which has significantly been used for a long time in rubber, dye, and veterinary industries. Moreover, it has also been used as an antidote against several heavy metals poisoning, in addition to its applications in the photographic developer and veterinary medicines. Gratifyingly, Rongalite has also shown its uses as the fungicidal, bactericidal and antioxidant in pharmaceutical formulation. Besides, it has also been used in material sciences, and also as a viable cosmetic hair‐dye‐color removers. Interestingly, in past decade, it has shown its high‐impact in the arena of synthetic organic chemistry serving as SO22− equivalent, C1 synthon donor, reducing agent/radical initiator or proton source ‐ to assemble diverse intricate organic molecules under operationally simple yet efficient conditions. However, the services of multiple features of Rongalite in synthetic chemistry are still at the research stage, and needs to be sophisticated to a higher level in many years to come. Considering the synthetic importance of this valued reagent, this review article presents the advancement made in the field of Rongalite chemistry in the past three years. This review article will update the researchers working in this arena about the advancement of Rongalite in the synthetic organic transformations as well as it will help readers wishing to deal with this easy‐to handle and eco‐friendly low‐cost commodity chemical. This review article updating the rongalite chemistry will be useful to the chemical community in general and synthetic chemists in particular.

Hydrolysis-oxidation of starch to formic acid in the presence of vanadium-containing molybdophosphoric heteropoly acid (H3+xPMo12-xVxO40): Effect of acidity and vanadium content on the yield of formic acid

Formic acid (FA) is an important chemical commodity as well as a promising medium for hydrogen storage and hydrogen production. Herein, a one-pot hydrolysis-oxidation of starch to formic acid (FA) catalyzed by molybdovanadophosphoric heteropoly acids (H3+xPMo12-xVxO40, x = 1, 2, 4, and 5) (PMo12-xVx) as bifunctional catalysts was demonstrated. The reaction was investigated at 120–150 °C. 2–5 MPa of gas mixture (O2/N2 - 20/80 vol/vol) was used as the oxidant. The rate of starch hydrolysis to glucose was found to decrease with decreasing the strength of PMo12-xVx. The yield of FA was demonstrated to depend on the number of V atoms in the framework of heteropoly anion. The initial rate of FA formation rose with an increasing number of V atoms. However, multi-substituted HPA favors overoxidation of the reaction mixture. Maximum yield of formic acid reached 67 % in 7 h under optimal conditions.

A process insight into production of ethyl levulinate via a stepwise fractionation

Ethyl levulinate (EL) is a key biomass-derived compounds due to its socio-economic benefits for the synthesis of commodity chemicals. Herein, we proposed an efficient one-step bamboo conversion to EL in ethanol, and a novel stepwise fractionation to purify EL and lignocellulose degradation products. A proton acid, due to its high catalytic efficiency, yielded 26.65 % EL in 120 min at 200 °C. The productions of ethyl glucoside and 5-ethoxymethylfurfural were analyzed in terms of by-products formation. To the best of our knowledge, there is no single report on catalyst for one step synthesis of EL directly from bamboo, as well as a stepwise fractionation to purify EL. Due to similar physiochemical properties in each fraction, the platform molecules could broaden a new paradigm of bamboo biomass utilization for renewable energy and value-added biochemicals. In addition, glucose, ethyl glucoside, corn starch, and microcrystalline cellulose were also investigated as substrates, so that the reaction intermediates of this one-pot procedure were identified and a possible reaction mechanism was proposed.

Heterologous expression of a fully active Azotobacter vinelandii nitrogenase Fe protein in Escherichia coli.

The heterologous expression of a fully active Azotobacter vinelandii Fe protein (AvNifH) has never been accomplished. Given the functional importance of this protein in nitrogenase catalysis and assembly, the successful expression of AvNifH in Escherichia coli as reported herein supplies a key element for the further development of heterologous expression systems that explore the catalytic versatility of the Fe protein, either on its own or as a key component of nitrogenase, for nitrogenase-based biotechnological applications in the future. Moreover, the "clean" genetic background of the heterologous expression host allows for an unambiguous assessment of the effect of certain nif-encoded protein factors, such as AvNifM described in this work, in the maturation of AvNifH, highlighting the utility of this heterologous expression system in further advancing our understanding of the complex biosynthetic mechanism of nitrogenase.

Reaction Pathways for Synthesis of Four Carbon Chemicals from Sugars and Sugar Derived Platform Chemicals

AbstractChemicals with a four‐carbon chain (C4 chemicals), like succinic acid, maleic acid, 1,4‐butanediol, and tetrahydrofuran are extensively used as commodity chemicals and polymer precursors. Currently, these chemicals are commercially synthesized from petrochemical based feedstocks. There is a growing interest in catalytic pathways for producing these and other C4 chemicals from biomass. However, biomass is mainly composed of hexose and pentose sugars and the natural abundance of a C4 feedstock is low. This review summarizes the current development in catalytic pathways for C4 chemical synthesis from biomass derived sugars and its derivatives and suggests future direction of research.

Comparative analysis of CO2 reduction by soluble Escherichia coli formate dehydrogenase H and its selenocysteine-to-cysteine substitution variant

Metal-dependent formate dehydrogenases (Me-FDHs) are highly active CO2-reducing enzymes operating at low redox potentials and employ either molybdenum or tungsten to reduce the bound substrate. This makes them suitable for electrochemical applications such as fossil-free production of commodity chemicals utilizing renewable energy. Electrocatalytic CO2 reduction by cathode-immobilized Me-FDHs has been recently demonstrated and rational protein engineering can be used to optimize Me-FDHs for various carbon reduction reactions. In the present study, CO2 reduction by soluble monomeric Escherichia coli formate dehydrogenase H (EcFDH-H) was demonstrated and the function of its nucleophilic selenocysteine residue as a transient ligand of a centrally bound molybdenum atom was investigated. Kinetic analysis of the wildtype enzyme revealed maximum CO2 reduction rates of 44 ± 6 s−1 at pH 5.8 that was decreased to 19% and 0% in the case of selenocysteine substitution with the structural homologues cysteine and serine, respectively. Further selenocysteine-to-cysteine substitution effects included an increased acid tolerance as well as stronger inhibition by nitrate and azide indicating a shift of the Mo oxidation state from IV to VI. Conversely, a destabilizing effect on the oxidized Mo(VI) center could be assigned to the native selenocysteine residue that may facilitate the observed efficient CO2 reduction by rapid transition between Mo oxidation states. Taken together, the performed characterization of EcFDH-H as a catalyst for CO2 reduction and the selenocysteine substitution analysis furthers the understanding of the active-site structure of Me-FDHs and thereby supports the development of more efficient biocatalysts for CO2 reduction.

Experimental screening of metal nitrides hydrolysis for green ammonia synthesis via solar thermochemical looping

Ammonia is a fundamental chemical commodity for fertilizers and as a novel energy vector. Solar-driven ammonia synthesis is proposed as a sustainable alternative to the catalytic energy-intensive and CO2-emitting Haber-Bosch process. The considered thermochemical process aims to produce ammonia from nitrogen and water (N2 + 3H2O → 2NH3 + 1.5O2) via redox cycles using a solar heat source, thus bypassing the supply of H2 or electricity. Metal oxide/nitride redox pairs can be employed for this cyclic process. The exothermal hydrolysis reaction of nitrides produces ammonia (MxNy + 3H2O → 2NH3 + Mx’Oy’), and is followed by one or several regeneration steps (Mx’Oy’+N2 → MxNy+3/2O2) requiring a heat supply from concentrated solar energy. This study aims to experimentally identify the most suitable metal nitrides in the hydrolysis step for ammonia synthesis based on solar-driven chemical-looping. As a result, FeN, CrN, BN, and Si3N4 turned out to be irrelevant candidates for NH3 production, as the hydrolysis yield was poor up to 1000 °C. In contrast, AlN, Li3N, Ca3N2, Mg3N2, TiN, and ZrN exhibited noteworthy reactivity depending on the temperature. The hydrolysis rate of AlN was significantly enhanced only above 1100 °C, TiN showed an increasing NH3 production rate with temperature (reaching 3.4 mmol/min/g at 1000 °C), while an optimum at 750 °C was unveiled for complete ZrN conversion (corresponding to the highest rate of 34.2 mmol/min/g). Hydrolysis of Li3N, Ca3N2, and Mg3N2 was complete at lower temperatures (∼200 °C), with NH3 yields of 5.9, 4.9, and 18.6 mmol/g, respectively. Solar-driven regeneration of metal nitrides at high temperature will be then necessary to demonstrate the complete feasibility of thermochemical cycles for green ammonia synthesis.

Arenium-ion-catalysed halodealkylation of fully alkylated silanes.

'Organic silicon' is not found in nature but modern chemistry is hard to imagine without silicon bound to carbon. Although silicon-containing commodity chemicals such as those emerging from the 'direct process'1-4 look simple, it is not trivial to selectively prepare aryl-substituted and alkyl-substituted (functionalized) silicon compounds, known as silanes. Chlorosilanes such as Me4-nSiCln (n = 1-3) as well as SiCl4 (n = 4) are common starting points for the synthesis of silicon-containing molecules. Yet these methods often suffer from challenging separation problems5. Conversely, silanes with four alkyl groups are considered synthetic dead ends. Here we introduce an arenium-ion-catalysed halodealkylation that effectively converts Me4Si and related quaternary silanes into a diverse range of functionalized derivatives. The reaction uses an alkyl halide and an arene (co)solvent: the alkyl halide is the halide source that eventually engages in a Friedel-Crafts alkylation with the arene to regenerate the catalyst6, whereas the arenium ion acts as a strong Brønsted acid for the protodealkylation step7. The advantage of the top-down halodealkylation methodology over reported bottom-up procedures is demonstrated, for example, in the synthesis of a silicon drug precursor. Moreover, chemoselective chlorodemethylation of the rather inert Me3Si group attached to an alkyl chain followed by oxidative degradation is shown to be an entry into Tamao-Fleming-type alcohol formation8,9.

Utilization of lignocellulosic hydrolysates for photomixotrophic chemical production in Synechococcus elongatus PCC 7942

To meet the need for environmentally friendly commodity chemicals, feedstocks for biological chemical production must be diversified. Lignocellulosic biomass are an carbon source with the potential for effective use in a large scale and cost-effective production systems. Although the use of lignocellulosic biomass lysates for heterotrophic chemical production has been advancing, there are challenges to overcome. Here we aim to investigate the obligate photoautotroph cyanobacterium Synechococcus elongatus PCC 7942 as a chassis organism for lignocellulosic chemical production. When modified to import monosaccharides, this cyanobacterium is an excellent candidate for lysates-based chemical production as it grows well at high lysate concentrations and can fix CO2 to enhance carbon efficiency. This study is an important step forward in enabling the simultaneous use of two sugars as well as lignocellulosic lysate. Incremental genetic modifications enable catabolism of both sugars concurrently without experiencing carbon catabolite repression. Production of 2,3-butanediol is demonstrated to characterize chemical production from the sugars in lignocellulosic hydrolysates. The engineered strain achieves a titer of 13.5 g L−1 of 2,3-butanediol over 12 days under shake-flask conditions. This study can be used as a foundation for industrial scale production of commodity chemicals from a combination of sunlight, CO2, and lignocellulosic sugars.

Chemodialysis of organic acids using ABPBI-based hollow fiber membranes

Organic acids are a class of essential commodity chemicals used in various industries. Their production methods are shifting from conventional chemicals to fermentation, driven by green process strategies, environmental regulations, cost feasibility, etc. Separating formed acid from the fermentation broth is a primary technological barrier. Conventional methods are complex and impose environmental issues. A promising approach, ‘Chemodialysis,’ capable of transforming the techno-economical feasibility of acid recovery scenario by reducing the number of steps, needs further investigation. This work evaluates scalable hollow fiber membranes based on poly(2,5-benzimidazole) (ABPBI) for chemically assisted dialysis, viz., Chemodialysis. Sorption analyses of commercially significant organic acids (acetic, lactic, and glycolic acid) and nonacidic solutes (NaCl and glucose) were performed using conventional flat sheet samples to assess their role in governing permeation characteristics. The transport properties of acids in the presence of NaCl and glucose as co-solutes were analyzed using hollow fiber membranes. The high selectivity of acid over nonacidic solutes ranges from 400-22,400, coupled with high acid permeability, enhances the applicability of Chemodialysis for the separation of acids using hollow fiber membranes. The fluxes of acids (acetic, glycolic, and lactic) through dense, ∼100 μm thick, scalable hollow fiber membranes ranging from 10.9 to 13.12 g/m2h are highly appreciable.