Petrochemical Routes Research Articles

Sustainability of Enzymatic Monomer Synthesis: Evaluation via Comparison of Petrochemical and Enzymatic Alkene Epoxidation by Life Cycle Assessment.

Life cycle assessment (LCA) was used, next to green chemistry concepts, to compare the full environmental impacts of the epoxidation of a bio-based monomer, which can be used for the synthesis of vitrimers. On a laboratory scale, the synthesis of the monomer can either be done via a petrochemical route or via an enzymatic reaction pathway. Both reaction pathways were initially optimized to minimize the impact of suboptimal routes on the sustainability evaluation. The subsequent assessment of the enzymatic routes shows lower impact factors for most criteria compared to the petrochemical routes. A significant drawback of the enzymatic reaction, however, is its electricity consumption. The yields of the respective reactions also proved to be crucial; realistic changes in yields revealed the petrochemical reaction to be more sustainable in some cases. LCA is therefore a valuable tool for the preliminary evaluation of the developed synthesis pathways and to identify the critical adjustments needed to increase the sustainability of each reaction.

Eco-efficient downstream processing of 1,3-propanediol applicable to various fermentation processes

PDO (1,3-propanediol) is a platform chemical that is obtained by petrochemical routes and by fermentation. The latter needs relatively complex downstream processing after fermentation, due to the modest concentration of the high-boiling product, and the presence of microorganisms and many impurities in the fermentation medium. This novel research proposes an original large-scale (production capacity of 23 – 32 ktonne/y) process for the final purification of PDO and dominant by-products, from the fermentation of glucose or glycerol. Following the initial microfiltration, diafiltration, ultrafiltration and ion exchange steps, heat pump-assisted vacuum distillation was implemented to remove most of the water from the broth. Afterwards, an advanced highly-integrated dividing-wall column was designed to allow the final purification of PDO (product purity > 99.9 wt%) from light and heavy by-products. Fermentation by-products that are present in significant amounts can also be recovered and valorized. Overall, the developed final purification processes demonstrate cost-effectiveness (0.150 – 0.274 $/kg) and energy-efficiency (1.258 – 3.175 kWthh/kg) which contributes to the competitiveness of the overall downstream processing (0.256 – 0.384 $/kg and 1.487 – 3.496 kWthh/kg).

Techno-economic viability of bio-based methyl ethyl ketone production from sugarcane using integrated fermentative and chemo-catalytic approach: Process integration using pinch technology

Butanediols are versatile platform chemicals that can be transformed into a spectrum of valuable products. This study examines the techno-commercial feasibility of an integrated biorefinery for fermentative production of 2,3-butanediol (BDO) from sucrose of sugarcane (SC), followed by chemo-catalytic upgrading of BDO to a carbon-conservative derivative, methyl ethyl ketone (MEK), with established commercial demand. The techno-economics of three process configurations are compared for downstream MEK separation from water and co-product, isobutyraldehyde (IBA): (I) heterogeneous azeotropic distillation of MEK-water and extractive separation of (II) MEK and (III) MEK-IBA from water using p-xylene as a solvent. The thermal efficiency of these manufacturing processes is further improved using pinch technology. The implementation of pinch technology reduces 8% of BDO and 9–10% of MEK production costs. Despite these improvements, raw material and utility costs remain substantial. The capital expenditure is notably higher for MEK production from SC than BDO alone due to additional processing steps. The extraction based MEK separation is the simplest process configuration despite marginally higher capital requirements and utility consumption with slightly higher production costs than MEK-water azeotropic distillation. Economic analysis suggests that bio-based BDO is cost-competitive with its petrochemical counterpart, with a minimum gross unitary selling price of US$ 1.54, assuming a 15% internal rate of return over five-year payback periods. However, renewable MEK is approximately 16–24% costlier than the petrochemical route. Future strategies must focus on reducing feedstock costs, improving BDO fermentation efficacy, and developing a low-cost downstream separation process to make renewable MEK commercially viable.

Experimental investigation on nontoxic solvents for separation of vanillic acid

AbstractBACKGROUNDVanillic acid, an aromatic carboxylic acid and a derivative of vanillin, is used as an additive in consumer goods for its aroma. Previously, most vanillic acid was produced through a petrochemical route, but as a consequence of stringent environmental policies, it is now produced by the biotransformation of ferulic acid. Vanillic acid is also found in the wastewater streams of paper‐pulp industries and olive‐oil mills. So, recovering vanillic acid from fermentation broth, either during bioproduction or from a wastewater stream, while minimizing toxicity, is a difficult task. In order to reduce the toxicity substantially, bio‐based solvents such as sunflower, mustard and rice bran oils were employed as diluents along with tri‐n‐butyl phosphate (TBP) as extractant in order to recover vanillic acid by reactive extraction.RESULTSThe extraction performance was elucidated using terms such as distribution ratio, extraction efficiency, loading ratio and equilibrium complexation constant for different extractant–diluent combinations. The highest extraction efficiency and distribution ratio for the different solvents were in the following order: TBP + sunflower‐oil (72.02%–92.47%; 2.57–12.29) > TBP + rice bran‐oil (65.56%–90.55%; 1.90–9.58) > TBP + mustard‐oil(64.03%–89.87%; 1.78–8.87). The theoretical number of stages was determined as 4 to achieve a targeted extraction efficiency of 90%; these predictions were borne out experimentally.CONCLUSIONIn this study, vanillic acid was recovered from the aqueous phase using tri‐n‐butyl phosphate in sustainable, environmentally friendly, bio‐based solvents such as rice bran oil, sunflower oil and mustard oil. © 2024 Society of Chemical Industry (SCI).

Design‐of‐Experiments‐Based Optimisation of Vanillin Yield from Kraft Lignin Using Pulse Electrolysis and Thermolysis

AbstractThe electrification of the production of fine chemicals has received increased interest in combating petrochemical routes with a high carbon footprint. Oxidising biomass from waste streams with concomitant hydrogen production, such as the transformation of lignin to vanillin, would be a great asset. Here, we show the combination of activity screening using a scanning droplet cell on a thin‐film Ni−Fe library and performance testing in a flow‐through cell with pulse electrolysis. The identified optimal Ni−Fe material composition was prepared on Ni foam with a polymer/metal precursor spray method. Full factorial and Doehlert matrix designs were employed to better comprehend each parameter‘s effects on the complex system. The best conditions for the electrooxidation of Kraft lignin at room temperature were at E1st=1.36 V vs RHE, t1st=1 s for the first pulse and E2nd=1.60 V vs RHE and t2nd=15 s for the second pulse, leading to the significantly improved production of 2.15 μmols of vanillin at room temperature. Pulsed chronopotentiometry was demonstrated to be a cost‐effective and robust technique with a simple setup for the valorisation of Kraft lignin. Combined with a subsequent thermolysis step, 8.05 μmols of vanillin were obtained.

Life Cycle Analysis of Succinic Acid Production in the Brazilian Biorefinery Context

Succinic acid is an essential component of the chemical industry. Traditionally produced from fossil resources, its sustainable production using renewable resources faces challenges due to the complexities of cultivation and purification. This study assessed the environmental impacts of succinic acid production from sugarcane through a life cycle analysis and compared it with three other scenarios: using sorghum, apple pomace, and the traditional chemical route. Employing the ReCiPe midpoint methodology with a cradle-to-gate approach, the analysis highlighted significant environmental impacts linked to the agricultural stage in the sugarcane process. The use of pesticides, fertilizers, and energy demand resulted in elevated impacts compared to other stages of the process. The other scenarios also presented strong contributions in the purification stages. The production from sugarcane proved advantageous compared to other scenarios, minimizing impacts in 6 out of 10 categories. It is evident that the selection of the correct biomass is crucial for process sustainability, and the use of second-generation inputs can help reduce impacts in the agricultural stage. However, advancements in the fermentation stage are necessary, along with a reduction in the complexity of the purification steps. This study emphasizes the potential of renewable succinic acid production from sugarcane juice in the Brazilian scenario. Utilizing this process could reduce succinic acid’s environmental impacts by 70% to 99% compared to the petrochemical route. The process should be considered as a sustainable alternative to be included in the portfolio of biorefineries, enhancing factory profitability.

Molecular design and experimental study on the alkylation of benzene with C6 olefin dimer with Lewis acidic monoamine ionic liquids and its sulfonate surfactant properties

Long-chain alkyl benzene (LAB), conventionally manufactured by petrochemical routes, is an important intermediate for the synthesis of high-value chemicals, especially detergents and oil displacement agents. The preparation of LAB from coal-based olefins has attracted extensive research interest. In this work, the alkylation activity of four Lewis acidic monoamine chloroaluminate ionic liquids (LAMCILs), designed by AlCl3 and monoamine hydrochloride with alkyl chains of different lengths, was predicted by quantum chemical calculations using the synthesis of 1-methyl-1-butylheptylbenzene (MBHB) with benzene and C6 olefin dimer as a model reaction. The HOMO*-LUMO* gap indicated that the alkylation activity was enhanced with increasing alkyl chain length of the organic amine molecules in the LAMCILs, in the following order: [n-C6H13NH3]Cl-AlCl3 > [n-C4H9NH3]Cl-AlCl3 > [n-C3H7NH3]Cl-AlCl3 > [C2H5NH3]Cl-AlCl3. These four LAMCILs were successfully synthesized and used to catalyze the alkylation of benzene with the C6 olefin dimer. The experimental results are consistent with the calculated results. The UV/VIS characterization showed that their Hammett acidity function (H0) increased as the alkyl chain of organic monoamine molecules in the LAMCILs extended. Therefore, a two-way correlation between the HOMO*-LUMO* gap, MBHB yield and Hammett acidity function can be established. Furthermore, the effect on the yield of MBHB was investigated by the method of metal chloride modified [n-C4H9NH3]Cl-AlCl3 ionic liquids. The results showed that the CuCl2-modified [n-C4H9NH3]Cl-AlCl3 ionic liquid had better catalytic activity in this study. Under optimal reaction conditions, the conversion of the C6 olefin dimer and selectivity toward MBHB reached 100 % and 91.34 %, respectively. Finally, the surfactant properties of sodium 1-methyl-1-butylheptylbenzene sulfonate (SMBHBS) were examined, and the results indicated that its surfactant properties were basically comparable to those of commercial LAS.

Process assessment of renewable-based acrylic acid production from glycerol valorisation

The continuous growth of biodiesel production via transesterification is leading to an increase in the generation and availability of the by-product glycerol. In this study, a glycerol-based process for the production of acrylic acid has been designed and simulated. The valorisation of glycerol route includes a two-step conversion process where glycerol is first dehydrated to acrolein and acrolein is selectively oxidised to acrylic acid. This renewable-based process is then compared in terms of heat integration and techno-economic performance to the traditional petrochemical route from propylene from a techno-economic and environmental point of view. The study includes the detailed design of the separation train in which azeotropic distillation is also assessed along with the sensitivity analysis of the most relevant variables of the process. Using a production basis of approximately 10,250 kg h−1 of acrylic acid (purity>99.5 wt%), results show that the glycerol route generates 37.3% less CO2 emissions than the propylene-based. From the heat integration analysis, slightly lower heating (96.6%) but higher cooling (32.4%) energy savings can be attained in the glycerol route as opposed to heating (100%) and cooling (21.6%) energy savings available in the propylene-based route. In terms of economics, the glycerol-based route has a lower capital expenditure (£74.0 million) and operating expenditure (£171.4 million yr−1) compared to the propylene route (£91.3 million and £180.2 million yr−1, respectively). Nevertheless, considering the use of raw material and its cost, the glycerol route is more demanding (1.96 kg h−1 of pure glycerol per kg h−1 of acrylic acid amounting to £138.6 million yr−1) than the propylene route (0.92 kg h−1 of propylene per kg h−1 of acrylic acid at £117.2 million yr−1).

Evolutionary engineering and chemical mutagenesis of Propionibacterium acidipropionici for improved propionic acid production from sugarcane-derived saccharides

Propionic acid (PA) is a 3-carbon carboxylic acid widely used in the chemical, food and pharmaceutical industries. Current production of PA is primarily via petrochemical routes and alternative sources using renewable feedstocks are desirable. The goal of the present study was to develop bacterial strains for efficient PA production by fermentation of sugarcane-derived saccharides in inverted sugarcane syrup. Adaptive evolution and random chemical mutagenesis of Propionibacterium acidipropionici were individually evaluated. Although evolutionary engineering proved to be a suitable strategy for producing strains tolerant to acid stress, chemical mutagenesis coupled with a novel screening methodology proved to be a superior strategy for strain improvement. The selected strain presented high PA productivity (0.55 g L−1 h−1) and titer (40 g L−1) in relation to the parental strain (0.38 g L−1 h−1 and 27 g L−1, respectively), in fermentations using inverted sugarcane syrup.

Succinic Acid Production from Glycerol by Actinobacillus succinogenes: Techno-economic, environmental, and exergy analyses

A significant commercial chemical namely succinic acid can be produced using glycerol from the biodiesel industry. Previously, key attributes of the upstream and the downstream processing in the synthesis of bio-based succinic acid were identified, which substantially influence the technological competitiveness compared to petroleum-based production. Accordingly, this study aims to simulate succinic acid production from glycerol with the most promising technology. The techniques of reactive extraction and direct crystallization, as well as the use of dimethyl sulfoxide (DMSO) as an electron acceptor, are investigated. Selected scenarios are evaluated based on techno-economic, energy, exergy, and greenhouse gas (GHG) emissions performances to acquire a broader perspective on the sustainability of the technology. The obtained results indicate that the addition of DMSO in the fermentation is key for the bio-based succinic acid production – the best profit of 190 million USD of the net present value, 33.3% of the internal rate of return, and 4.48 years of the payout period are estimated. Additionally, bio-based succinic acid production could compete with the petrochemical route, particularly the reduction of GHG by 26%. Therefore, the production of succinic acid from glycerol is feasible given the positive net present value and lower GHG emissions compared to the petrochemical route.

Conversion of acetate and glyoxylate to fumarate by a cell-free synthetic enzymatic biosystem

Fumarate is a value-added chemical that is widely used in food, medicine, material, and agriculture industries. With the rising attention to the demand for fumarate and sustainable development, many novel alternative ways that can replace the traditional petrochemical routes emerged. The in vitro cell-free multi-enzyme catalysis is an effective method to produce high value chemicals. In this study, a multi-enzyme catalytic pathway comprising three enzymes for fumarate production from low-cost substrates acetate and glyoxylate was designed. The acetyl-CoA synthase, malate synthase, and fumarase from Escherichia coli were selected and the coenzyme A achieved recyclable. The enzymatic properties and optimization of reaction system were investigated, reaching a fumarate yield of 0.34 mM with a conversion rate of 34% after 20 h of reaction. We proposed and realized the conversion of acetate and glyoxylate to fumarate in vitro using a cell-free multi-enzyme catalytic system, thus providing an alternative approach for the production of fumarate.

Propionic Acid Fermentation—Study of Substrates, Strains, and Antimicrobial Properties

Since milk whey is an abundant dairy by-product and a significant threat to the environment, its utilization is of great interest. The study compares valorization of lactose and lactates—the main carbon sources of whey—by fermentation—an environmentally friendly process. Antimicrobials released during fermentation by food-grade bacteria can help increase the microbiological safety of food. Propionic acid—a strong antimicrobial—is obtained mainly by the petrochemical route, yet there is increasing interest in its synthesis in biotechnological pathway. Five strains of propionic acid bacteria (Acidipropionibacterium acidipropionici, Propionibacterium cyclohexanicum, Propionibacterium freudenreichii, Acidipropionibacterium jensenii and Acidipropionibacterium thoenii) were investigated for their ability to produce organic acids and biomass using Na lactate or lactose as carbon sources. Selected fermentates were investigated for their antimicrobial efficacy during in vitro studies with foodborne pathogens: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. Results confirm that the production of acids and biomass is considerably influenced by the added carbon source. The tested fermentates have strong and specific antimicrobial activity against Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. In addition, inhibition of Staphylococcus aureus and Klebsiella pneumonia depends on the activity of produced bacteriocins. The article also discusses the possibility of increasing the antimicrobial activity of fermentates by acidification.

Experimental investigation on recovery of bio‐based protocatechuic acid using ionic liquids

AbstractBACKGROUNDThe production of protocatechuic acid (PCA) (which has significant applications in organic intermediates, chemical reagents, pharmaceuticals, dye synthesis, etc.) by fermentation is a potential replacement to the conventional petrochemical routes of carboxylic acid production. However, the extraction processes of these carboxylic acids from fermentation broths and dilute waste water using organic solvents imply additional environment hazards. Ionic liquids (ILs) have come to the focus because of their superior properties as well as environmentally friendly nature, and are being intensively used for separation processes. The equilibrium extraction efficiency for bio PCA using two imidazolium ILs – 1‐butyl‐3‐methylimidazolium tetrafluoroborate (bmimBF4) and 1‐butyl‐3‐methylimidazolium hexafluorophosphate (bmim‐PF6) – was investigated under isothermal conditions in diluent octanol. The distribution coefficient and extraction efficiency were determined to be much greater than those obtained with traditional extractants and diluents.RESULTSThis work is the first of its type to use ILs for PCA isolation. From the equilibrium extraction experiments conducted it was observed, in octanol, that the average distribution coefficients (KD) values for bmimBF4 and bmim‐PF6 were 5.3 and 5.36, respectively, with average extraction efficiencies of 83.84% and 84.08% at a lower IL concentration of 10% by volume, and the findings may be utilised to develop an extraction purification system for PCA separation from aqueous streams. Multiple stages of separation may lead to almost 100% recovery.CONCLUSIONPCA was efficiently extracted from aqueous solutions using bmimBF4 and bmim‐PF6 in octanol, providing preliminary practical information and theoretical support for PCA separation, purification and recovery. © 2022 Society of Chemical Industry (SCI).

Genome-scale metabolic modelling enables deciphering ethanol metabolism via the acrylate pathway in the propionate-producer Anaerotignum neopropionicum

BackgroundMicrobial production of propionate from diluted streams of ethanol (e.g., deriving from syngas fermentation) is a sustainable alternative to the petrochemical production route. Yet, few ethanol-fermenting propionigenic bacteria are known, and understanding of their metabolism is limited. Anaerotignum neopropionicum is a propionate-producing bacterium that uses the acrylate pathway to ferment ethanol and CO2 to propionate and acetate. In this work, we used computational and experimental methods to study the metabolism of A. neopropionicum and, in particular, the pathway for conversion of ethanol into propionate.ResultsOur work describes iANEO_SB607, the first genome-scale metabolic model (GEM) of A. neopropionicum. The model was built combining the use of automatic tools with an extensive manual curation process, and it was validated with experimental data from this and published studies. The model predicted growth of A. neopropionicum on ethanol, lactate, sugars and amino acids, matching observed phenotypes. In addition, the model was used to implement a dynamic flux balance analysis (dFBA) approach that accurately predicted the fermentation profile of A. neopropionicum during batch growth on ethanol. A systematic analysis of the metabolism of A. neopropionicum combined with model simulations shed light into the mechanism of ethanol fermentation via the acrylate pathway, and revealed the presence of the electron-transferring complexes NADH-dependent reduced ferredoxin:NADP+ oxidoreductase (Nfn) and acryloyl-CoA reductase-EtfAB, identified for the first time in this bacterium.ConclusionsThe realisation of the GEM iANEO_SB607 is a stepping stone towards the understanding of the metabolism of the propionate-producer A. neopropionicum. With it, we have gained insight into the functioning of the acrylate pathway and energetic aspects of the cell, with focus on the fermentation of ethanol. Overall, this study provides a basis to further exploit the potential of propionigenic bacteria as microbial cell factories.

MICROBIAL isoprene production: an overview.

Isoprene, a volatile C5 hydrocarbon, is a precursor of synthetic rubber and an important building block for a variety of natural products, solely being produced by petrochemical routes. To mitigate the ever-increasing contribution of petrochemical industry to global warming through significant carbon (CO2) evolution, bio-based process for isoprene production using microbial cell factories have been explored. Highly efficient fermentation-based processes have been studied for little over a decade now with extensive research on the rational strain development for creating robust strains for commercial isoprene production. Most of these studies involved sugars as feedstocks and using naturally occurring isoprene pathways viz., mevalonate and methyl erythritol pathway in E. coli. Recent advances, driven by efforts in reducing environmental pollution, have focused on utilization of inorganic CO2 by cyanobacteria or syngas from waste gases by acetogens for isoprene production. This review endeavors to capture the latest relevant progress made in rational strain development, metabolic engineering and synthetic biology strategies used, challenges in fermentation process development at lab and commercial scale production of isoprene along with a future perspective pertaining to this area of research.

Applications of Starch Biopolymers for a Sustainable Modern Agriculture

Protected cultivation in modern agriculture relies extensively on plastic-originated mulch films, nets, packaging, piping, silage, and various applications. Polyolefins synthesized from petrochemical routes are vastly consumed in plasticulture, wherein PP and PE are the dominant commodity plastics. Imposing substantial impacts on our geosphere and humankind, plastics in soil threaten food security, health, and the environment. Mismanaged plastics are not biodegradable under natural conditions and generate problematic emerging pollutants such as nano-micro plastics. Post-consumed petrochemical plastics from agriculture face many challenges in recycling and reusing due to soil contamination in fulfilling the zero waste hierarchy. Hence, biodegradable polymers from renewable sources for agricultural applications are pragmatic as mitigation. Starch is one of the most abundant biodegradable biopolymers from renewable sources; it also contains tunable thermoplastic properties suitable for diverse applications in agriculture. Functional performances of starch such as physicomechanical, barrier, and surface chemistry may be altered for extended agricultural applications. Furthermore, starch can be a multidimensional additive for plasticulture that can function as a filler, a metaphase component in blends/composites, a plasticizer, an efficient carrier for active delivery of biocides, etc. A substantial fraction of food and agricultural wastes and surpluses of starch sources are underutilized, without harnessing useful resources for agriscience. Hence, this review proposes reliable solutions from starch toward timely implementation of sustainable practices, circular economy, waste remediation, and green chemistry for plasticulture in agriscience

Engineering of phenylalanine dehydrogenase from Thermoactinomyces intermedius for the production of a novel homoglutamate.

The dramatic increase in healthcare costs has become a significant burden to this era. Many patients are unable to access medication because of the high price of drugs. Genetic engineering has made advances to increase the yield, titer, and productivity in the bio-based production of chemicals, materials of interest, and identification of innovative targets for drug discovery. Currently, the production of homoglutamate (α-Aminoadipic acid) involves petrochemical routes that are costly with low yield and often not suitable for industrial production. Here, we established the development of NADH-dependent homoglutamate by engineering NADH-dependent phenylalanine dehydrogenase (PDH) from Thermoactinomyces intermedius, which provides a novel tool for in-vivo metabolic engineering and in-vitro catalysis. Based on computational insight into the structure, we proposed the site-specific directed mutagenesis of the two important residues of PDH through docking simulations by AutoDock Vina which elucidated the binding mode of PDH with α-Ketoadipic acid and ligands. Our results demonstrated that the catalytic efficiency Km/Kcat of the final mutant Ala135Arg showed a 3-fold increase amination activity towards the ketoadipic acid as compared to the other mutant Gly114Arg, a double mutant Gly114Arg/Ala135Arg, and wild type TiPDH. Furthermore, we have introduced formate dehydrogenase as a cofactor regenerative system in this study which further made this study economically viable. Our study unfolds the possibility of biosynthesis of other non-proteinogenic amino acids that might be valuable pharmaceutical intermediaries.

Recent Advances in C5 and C6 Sugar Alcohol Synthesis by Hydrogenation of Monosaccharides and Cellulose Hydrolytic Hydrogenation over Non-Noble Metal Catalysts.

A new reality of the 21st century is the transition to a new type of economy and energy concepts characterized by the replacement of existing petrochemical routes to a bio-based circular economy. The needs for new strategies in obtaining basic products from bio-based resources with minimum CO2 traces has become mandatory. In this review, recent trends in the conversion of biomass-derived molecules, such as simple monomeric sugars and cellulose, to industrially important C5 and C6 sugar alcohols on heterogeneous catalysts based on non-noble metals are discussed focusing on the influence of catalyst structures and reaction conditions used on the substrate conversion and product selectivity. The challenges and prominent ideas are suggested for the further development of catalytic hydrogenation of naturally abundant carbohydrates to value-added chemicals on non-noble metal catalysts.

High-efficiency production of 5-aminovalerate in engineered Escherichia coli controlled by an anaerobically-induced nirB promoter

Biobased production of 5-aminovalerate (5AVA) from biomass can support a sustainable and economic biorefinery process to produce bio-based nylon 5 for food packaging materials. Cost-competitive production of 5AVA from biomass is a key factor in the successful commercialization of nylon 5. Bioproduction of 5AVA is a promising candidate for the industrial process to the current petrochemical route. In this study, we developed an artificial 2-keto-6-aminocaproate-mediated pathway for cost-competitive and high efficiency production of 5AVA in engineered Escherichia coli. Firstly, the combination of native l-lysine α-oxidase (RaiP) from Scomber japonicas, α-ketoacid decarboxylase (KivD) from Lactococcus lactis and aldehyde dehydrogenase (PadA) from Escherichia coli could efficiently convert l-lysine into 5AVA. Moreover, the engineered strains ML03-PnirB-RKP, ML03-PPL-PR-RKP, ML03-PM1-93-RKP induced by anaerobic condition, temperature-induced, constitutive expression instead of expensive isopropyl β-D-thiogalactoside were constructed, respectively. The use of nirB promoter induced by anaerobic condition not only could attain a higher titer of 5AVA than PL-PR and M1-93 promoters, but omit cost of expensive exogenous inducers. After the replacement of industrial materials, 5AVA titer successfully reached 33.68 g/L in engineered strain ML03-PnirB-RKP via biotransformation. This biotransformation process conduces to the cosmically industrial 5AVA bioproduction.

Techno-Economic Analysis of Producing Glacial Acetic Acid from Poplar Biomass via Bioconversion.

Most of the current commercial production of glacial acetic acid (GAA) is by petrochemical routes, primarily methanol carbonylation. GAA is an intermediate in the production of plastics, textiles, dyes, and paints. GAA production from biomass might be an economically viable and sustainable alternative to petroleum-derived routes. Separation of acetic acid from water is a major expense and requires considerable energy. This study evaluates and compares the technical and economic feasibility of GAA production via bioconversion using either ethyl acetate or alamine in diisobutylkerosene (DIBK) as organic solvents for purification. Models of a GAA biorefinery with a production of 120,650 tons/year were simulated in Aspen software. This biorefinery follows the path of pretreatment, enzymatic hydrolysis, acetogen fermentation, and acid purification. Estimated capital costs for different scenarios ranged from USD 186 to 245 million. Recovery of GGA using alamine/DIBK was a more economical process and consumed 64% less energy, due to lower steam demand in the recovery distillation columns. The estimated average minimum selling prices of GGA were USD 756 and 877/ton for alamine/DIBK and ethyl acetate scenarios, respectively. This work establishes a feasible and sustainable approach to produce GGA from poplar biomass via fermentation.