Acetone-butanol-ethanol Fermentation Process Research Articles

Solvent-Producing Clostridia Revisited.

The review provides an overview of the current status of the solvent-producing clostridia. The origin and development of industrial clostridial species, as well as the history of the industrial Acetone Butanol Ethanol fermentation process, is reexamined, and the recent resurgence of interest in the production of biobutanol is reviewed. Over 300 fully sequenced genomes for solvent-producing and closely related clostridial species are currently available in public databases. These include 270 genomes sourced from the David Jones culture collection. These genomes were allocated arbitrary DJ codes, and a conversion table to identify the species and strains has now been provided. The expanded genomic database facilitated new comparative genomic and phylogenetic analysis. A synopsis of the common features, molecular taxonomy, and phylogeny of solvent-producing clostridia and the application of comparative phylogenomics are evaluated. A survey and analysis of resident prophages in solvent-producing clostridia are discussed, and the discovery, occurrence, and role of novel R-type tailocins are reported. Prophage genomes with R-type tailocin-like features were detected in all 12 species investigated. The widespread occurrence of tailocins in Gram-negative species is well documented; this survey has indicated that they may also be widespread in clostridia.

Combination of pH adjusting and intermittent feeding can improve fermentative acetone-butanol-ethanol (ABE) production from steam exploded corn stover

Steam explosion (SE) is an effective and industrially scalable lignocellulose pretreatment method that can be used for second-generation acetone-butanol-ethanol (ABE) fermentation. Nevertheless, a series technical barrier including the high inhibitors content in hydrolysate, and low concentration and low yield of ABE production always hindered the availability of the SE technique. In this study, aiming to solve the above obstacles and boosting cellulosic ABE production, the ABE fermentation process was intensified by a novel fed-batch strategy that combined the pH adjusting with intermittent feeding. Results revealed that maintaining the pH at 6.5 for initial 12 h of cultivation ensures the smoothly shifting of the acidogenesis phase to solventogenesis phase of the C. acetobutylicum cells, so that avoided the acid crash. While the lag period of fermentation was obvious shorted by intermittent feeding the concentrated SE hydrolysate into the dilute broth. Consequentially, 17.75 g/L of ABE (containing 11.75 g/L of butanol) can be obtained after 48 h of inoculation, with the yield and productivity of ABE were 0.36 g/g (of sugars) and 0.37 g/L‧h, respectively. Correspondingly, 194.9 g of ABE (including 129.0 g of butanol) can be produced from 1 kg of dried corn stover. Therefore, the novel process intensifying method could obviously improve the biobutanol production, which showed high potential and applicability in large-scale ABE productions.

Pemisahan Butanol dari Campuran ABE Menggunakan Software Aspen Plus: Pengaruh Refluks Rasio terhadap Kandungan Butanol

Production of acetone-butanol-ethanol (ABE) through the fermentation process is one alternative that needs to be developed. Less economical in the ABE fermentation process is the difficulty of the separation process from the fermentation product and the by-products of the reaction. Among the separation process methods, such as extraction, distillation, adsorption, and gas stripping, the distillation method is still the most widely used method in the ABE separation process. The purpose of this study was to provide recommendations for predicting good ABE separation and producing optimum operating conditions to produce high % butanol content. Which is then simulated using Aspen Plus V11 software. This study varied the reflux ratio in the distillation column and the decanter operating temperature. The results showed that butanol purity reached 90.33% in the radfrac 1 column operated at a pressure of 1.3 atm with a reflux ratio of 5, the location of the 7th feed stage and the number of stages 11. Then proceed to the purification stage in the radfrac column 2 which is operated at a pressure of 2 atm with a reflux ratio of 5, the location of the 4th stage feed and the number of stages 5. The decrease in the reflux ratio of the radfrac column causes a decrease in the butanol content at the bottom so that the purity of butanol also decreases and decreases % recovery or recovery of butanol. This is also followed by the location of the feed stage, which is getting higher, and the number of stages is increasing.

Polyether-block-amide thin-film composite hollow fiber membranes for the recovery of butanol from ABE process by pervaporation

• PEBA thin-film composite hollow fiber were fabricated by coating. • Pervaporation tests were carried out with membranes of different active layer thicknesses. • Good performance of membranes for recovery of butanol from ABE mixtures. • Membrane support has a relevant contribution to mass transfer resistance. This work reports the continuation of previous efforts to recover butanol from the ABE (acetone-butanol-ethanol) fermentation process by pervaporation (PV). A key aspect to improve the efficiency of the technology is the membrane used to perform the selective butanol separation; hence, this study focuses on the implementation of hollow fiber (HF) membrane configuration for the ABE separation by PV as opposed to flat sheet membrane configuration. The HF membrane preparation was done by dip coating, a frequently used process for the production of HF membranes, which involves the deposition of a thin film of a coating solution. Different thicknesses of the active layer were obtained by modifying the polymer content in the coating solution, allowing later to evaluate the influence of the thickness on the separation performance. This study includes a description of the procedure to prepare selective membranes, its characterization and an analysis of the influence of operating conditions on membrane separation performance. SEM and water contact angle were used to characterize the produced membranes. The mass transport phenomena in the pervaporation process were characterized using a resistances-in-series model. The results allow to adopt a criterion to select the most suitable thickness for the membrane active layer, which allows to achieve an adequate separation performance, and reveal the importance in the choice of the membrane support material. Finally, a comparative analysis of the self-made hollow fiber membranes performance in terms of flux, separation factor and PSI with respect to those found in the literature is presented.

Comparison of acetone–butanol–ethanol fermentation and ethanol catalytic upgrading as pathways for butanol production: A techno-economic and environmental assessment

Butanol is an important compound used as a building block for producing value-added products and an energy carrier. The main butanol production pathways are conventional acetone–butanol–ethanol (ABE) fermentation and catalytic upgrading of ethanol. On the other hand, the application of biomass as a promising substrate for biofuel production has been widely considered recently. However, few studies have compared different butanol production pathways using biomass as raw material. In light of that, the present work aims (i) to provide a short review of the catalytic ethanol upgrading and (ii) to compare conventional ABE fermentation and catalytic ethanol upgrading processes from the economic and environmental perspectives. Aspen Plus v9.0 was used to simulate both processes. The economic and environmental assessments were carried out considering the Colombian economic context, a gate-to-gate approach, and single impact categories. Considering a processing scale of 1000 ton/d, the conventional ABE fermentation process presented a more favorable technical, economic, and environmental performance for butanol production from biomass. It also offered lower net energy consumption (i.e., 57.9 GJ/ton of butanol) and higher butanol production (i.e., 2.59 ton/h). Nevertheless, the proposed processing scale was insufficient to reach economic feasibility for both processes. To overcome this challenge, the minimum processing scale had to be higher than 1584 ton/d and 1920 ton/d for conventional ABE fermentation and catalytic ethanol upgrading, respectively. Another critical factor in enhancing the economic feasibility of both butanol production pathways was the minimum selling price of butanol. More specifically, prices higher than 1.56 USD/kg and 1.80 USD/kg would be required for conventional ABE fermentation and catalytic ethanol upgrading, respectively. From the environmental impact point of view, the conventional ABE fermentation process led to a lower potential environmental impact than catalytic ethanol upgrading (0.12 PEI/kg vs. 0.18 PEI/kg, respectively).

A Highly Water-Stable meta-Carborane-Based Copper Metal-Organic Framework for Efficient High-Temperature Butanol Separation.

Biofuels are considered sustainable and renewable alternatives to conventional fossil fuels. Biobutanol has recently emerged as an attractive option compared to bioethanol and biodiesel, but a significant challenge in its production lies in the separation stage. The current industrial process for the production of biobutanol includes the ABE (acetone-butanol-ethanol) fermentation process from biomass; the resulting fermentation broth has a butanol concentration of no more than 2 wt% (the rest is essentially water). Therefore, the development of a cost-effective process for separation of butanol from dilute aqueous solutions is highly desirable. The use of porous materials for the adsorptive separation of ABE mixtures is considered a highly promising route, as these materials can potentially have high affinities for alcohols and low affinities for water. To date, zeolites have been tested toward this separation, but their hydrophilic nature makes them highly incompetent for this application. The use of metal-organic frameworks (MOFs) is an apparent solution; however, their low hydrolytic stabilities hinder their implementation in this application. So far, a few nanoporous zeolitic imidazolate frameworks (ZIFs) have shown excellent potential for butanol separation due to their good hydrolytic and thermal stabilities. Herein, we present a novel, porous, and hydrophobic MOF based on copper ions and carborane-carboxylate ligands, mCB-MOF-1, for butanol recovery. mCB-MOF-1 exhibits excellent stability when immersed in organic solvents, water at 90 °C for at least two months, and acidic and basic aqueous solutions. We found that, like ZIF-8, mCB-MOF-1 is non-porous to water (type II isotherm), but it has higher affinity for ethanol, butanol, and acetone compared to ZIF-8, as suggested by the shape of the vapor isotherms at the crucial low-pressure region. This is reflected in the separation of a realistic ABE mixture in which mCB-MOF-1 recovers butanol more efficiently compared to ZIF-8 at 333 K.

Pervaporation Performance of Polydimethylsiloxane-Polyvinylidene Fluoride Composite Membrane for Butanol Recovery from Model Solutions and Acetone-Butanol-Ethanol Fermentation Broth

Pervaporation has been identified as the most promising separation technology for butanol recovery in acetone-butanol-ethanol (ABE) fermentation, to overcome two main obstacles, low yield and high separation cost in the industrial-scale butanol production. In this work, we investigated the pervaporation performance of a thin flat polydimethylsiloxane (PDMS)-polyvinylidene fluoride (PVDF) composite membrane for butanol recovery from model solutions and ABE fermentation broth. The PDMS-PVDF composite membrane exhibited a high total flux of 1330 g m–2 h–1, and relatively higher separation factors of 21.2, 17.2, and 4.5 for acetone, butanol, and ethanol, respectively, with ABE-water solution. Compared to ABE-water solution, the total flux decreased by 3.25% and separation factors increased by 1.40%, 3.21%, and 3.92% for acetone, butanol, and ethanol in ABE fermentation broth, indicating that the negative effect of impermeable components present in the ABE fermentation broth was negligible. The excellent pervaporation performance and long-term operational stability of PDMS-PVDF composite membrane can enhance the efficacy of butanol recovery, thus it has potential to be used as a competitive pervaporation membrane in ABE fermentation process.

Isolation of Different Clostridium Isolates for Acetone-Butanol-Ethanol (ABE) Production from Sargassum sp.

Macroalgae with several species are an abundant, carbon-neutral renewable resource and rich in carbohydrates which make it suitable for biobutanol production. Recently, due to advantages of biobutanol as a liquid biofuel, it can be used as a substitute for gasoline and diesel. Many researches mentioned that, different Clostridium species are able to use fermentable sugars for production of biobutanol from different biomasses through ABE (Acetone- Butanol- Ethanol) fermentation process. In this study the (Sargassum sp.) was used as carbon source for biobutanol production. Thirty-three anaerobic mesophilic isolates were isolated on RCM medium from five soil cultivated with different crops. Only thirteen spore forming, mesophilic, anaerobic Clostridium isolates used for the fermentation process. 100 g/L from Sargassum sp were hydrolyzed by sulfuric acid (6 % (v/v)) followed by thermal pretreatment at 121°C for 20 minutes to produce total reducing sugars (24.151 ± 0.273 g/L), which were fermented by Clostridium isolates. The most promising isolate (HG1) which produce the highest butanol level, acetone and ethanol (3.743, 1.401 and 1.031 g/l) respectively was identified according to Butanol dehydrogenases (bdhA) gene analysis as Clostridium acetobutylicum. This paper emphasizes the importance of (Sargassum sp.) as a renewable feedstock for the biobutanol production.

Greenhouse gas emission of corn butanol in life-cycle

Since advances in the ABE (acetone-butanol-ethanol) fermentation process in recent years have led to significant increases in its productivity and yields, the production of butanol and its use in motor vehicles have become an option worth evaluating. It employs a well-to-wheels (WTW) analysis tool, and ascertains Bio-butanol-related WTW activities including corn farming, corn transportation, butanol production, butanol transportation, and vehicle operation. According to the 3 kinds of by-product of different methods of distribution, calculation and comparison of the greenhouse gas emissions in the life cycle of corn alcohol. The results show that 1) life cycle GHG emission of the corn butanol reduced 26%—49.5% according to the energy value method and product substitution method;2) bio-acetone that was coproduced with bio-butanol as an alternative to petroleum-based acetone could significantly reduce the life cycle GHG emission of butanol; 3) In the life cycle of the corn butanol, the main source of GHG emission was the use of natural gas, diesel and nitrogen, accounting for the total GHG emission by 53%, 21.4% and 13.38% respectively.

Recovery of bio-butanol from aqueous solution with ZIF-8 modified graphene oxide composite membrane

Recovery of butanol is a potential biofuel production process, which can be achieved through membrane separation technology. In this study, Zeolitic Imidazolate Framework-8 (ZIF-8) modified graphene oxide (ZGO) with polyether block amide (PEBA) was deposited on ceramic tubular substrate to prepare composite membrane for bio-butanol recovery. ZGO laminates can be used to form transport channels for butanol molecules to enhance the permeance. The affinity of laminate to butanol was improved because of the hydrophobic ZIF-8 particles. Therefore, the separation performance of ZGO/PEBA membrane was enhanced. The microstructure and chemical property of the ZGO/PEBA membranes were characterized. Different preparation and operation conditions were also investigated to optimize the separation performance. Moreover, ZGO/PEBA composite membranes were evaluated in model acetone-butanol-ethanol (ABE) solution, which also exhibited high butanol recovery performance. Therefore, this facile strategy may provide a potential application in the commercialized ABE fermentation process.

Smart fermentation engineering for butanol production: designed biomass and consolidated bioprocessing systems.

There is a renewed interest in acetone-butanol-ethanol (ABE) fermentation from renewable substrates for the sustainable and environment-friendly production of biofuel and platform chemicals. However, the ABE fermentation is associated with several challenges due to the presence of heterogeneous components in the renewable substrates and the intrinsic characteristics of ABE fermentation process. Hence, there is a need to select optimal substrates and modify their characteristics suitable for the ABE fermentation process or microbial strain. This "designed biomass" can be used to establish the consolidated bioprocessing systems. As there are very few reports on designed biomass, the main objectives of this review are to summarize the main challenges associated with ABE fermentation from renewable substrates and to introduce feasible strategies for designing the substrates through pretreatment and hydrolysis technologies as well as through the establishment of consolidated bioprocessing systems. This review offers new insights on improving the efficiency of ABE fermentation from designed renewable substrates.

A Hybrid Model of Multi-Objective Differential Evolution Algorithm and Various Decision-making Methods to Optimize the Batch ABE Fermentation Process

In recent years, biofuels have attracted considerable attention as renewable and clean source of energy and have been playing the role of suitable alternatives to fossil fuels. One of the most attractive types of biofuels is Acetone-Butanol-Ethanol (ABE) which is produced in a batch fermentation process by the anaerobic bacterium Clostridium acetobutylicum and sugar-based substrate as feedstock. In this paper, optimization of this process was carried out according to a bi-objective function. A hybrid model of Multi-Objective Differential Evolution (MODE) algorithm and distinguished decision-making methods, namely Linear programming technique for Multidimensional Analysis of Preference (LINMAP), Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and Shannon's entropy were applied to find the final optimal operating point. The initial concentration of substrate and the final operating time of the process were selected as decision variables to maximize two main objectives in terms of solvents yield and productivity. A Pareto optimal set presents a wide range of optimal operating points and a proper operating condition can be selected based on the necessities of the applicant. The best optimal point obtained by TOPSIS, according to the lowest value of deviation index, was also compared with the results of economic-based optimization.

Features of a Staged Acidogenic/Solventogenic Fermentation Process To Improve Butanol Production from Rice Straw

This study introduced an innovative two-stage fermentation process to maximize sugar utilization and biobutanol production from alkaline-pretreated rice straw. The new bioconversion process was composed of an acidogenic fermentation process followed by an acetone–butanol–ethanol (ABE) fermentation process. A sugar-rich hydrolysate (90.4 g/L reducing sugar) and a high acid content fermentation broth (33.9 g/L butyric acid), both produced from rice straw, were mixed together to increase the yield of the biofuels in the ABE fermentation process. Butyric acid and acetic acid generated from the acidogenic fermentation process play a critical role in the ABE fermentation process, which was confirmed by gene expression analysis of five messenger RNAs. Compared with the conventional process, this unique strategy increased the final butanol concentration from 6.2 to 15.9 g/L with 3-fold lower cellulase loading. Furthermore, an enhanced production of 149 g butanol and 36 L hydrogen gas from 1 kg rice straw was achi...

Simultaneous acetone-butanol-ethanol fermentation, gas stripping, and full-cell-catalyzed esterification for effective production of butyl oleate.

In this study, aiming to improve the economic feasibility of acetone-butanol-ethanol (ABE) fermentation process, generate valuable products and extend the product chain, esterification catalyzed by Candida sp. 99-125 cells was hybrid with the ABE fermentation-gas-stripping integration system. The gas-stripping condensate that contained concentrated ABE products was directly used for esterification without the participation of toxic organic solvents. Full-cell catalysis temperature and the cell dosage rate on oleate production were evaluated and optimized in the esterification process. Under the optimized conditions (35°C, 8% of cells), ~ 68% of butyl oleate and ~ 12% of ethyl oleate were obtained after 4h of esterification. The Candida sp. 99-125 cells were able to be reused for at least four cycles. The novel cascade process showed environmental benefits, which also showed promising in improving the economic feasibility of the conventional ABE fermentation process.

Kinetic modelling and simulation of batch, continuous and cell-recycling fermentations for acetone-butanol-ethanol production using Clostridium saccharoperbutylacetonicum N1-4

A kinetic model describing acetone-butanol-ethanol (ABE) production applicable to both single substrate fermentations of glucose and xylose as well as co-fermentation of the substrates has been developed. The model accounts for carbon catabolite repression as well as the inhibition of kinetic rates at high substrate concentrations (∼90 g l−1). Model parameters were obtained through kinetic fitting to previously report experimental data. The model was used to study the design and operation of a continuous ABE fermentation process (with and without recycle of biomass). For continuous operation, it was shown that multiple steady-states exist at low dilution rates. For operation with recycle of biomass, the influence of recycle rate on both biomass concentration and ABE productivity were studied. The results indicate that for a range of recycle and dilution rates, ABE productivity can increase to 16 g l−1 h−1 (10 times higher than that without biomass recycling), consistent with experimental results.

Assessment of Acidified Fibrous Immobilization Materials for Improving Acetone-Butanol-Ethanol (ABE) Fermentation

Acetone-butanol-ethanol (ABE) fermentation using Clostridium acetobutylicum is a process that can be used to produce butanol, which can be utilized as an alternative to petroleum-based fuels. Immobilization of the bacteria using three different fibrous materials was studied in order to see how to improve the ABE fermentation process. The results were compared to those of non-immobilized bacteria. Modal and charcoal fibers had OD levels below one at 72 h with the butanol concentration reaching 11.0 ± 0.5 and 10.7 ± 0.6 g/L, respectively, each of which were close to the free cell concentration at 11.1 ± 0.4 g/L. This suggests that bacteria can be efficiently immobilized in these fibrous materials. Although an extended lag phase was found in the fermentation time course, this can be easily solved by pre-treating fibrous materials with 3.5% HCl for 12 h. From comparisons with previous studies, data in this study suggests that a hydrophilic surface facilitates the adsorption of C. acetobutylicum.

Industrial production of acetone and butanol by fermentation-100 years later.

Microbial production of acetone and butanol was one of the first large-scale industrial fermentation processes of global importance. During the first part of the 20th century, it was indeed the second largest fermentation process, superseded in importance only by the ethanol fermentation. After a rapid decline after the 1950s, acetone-butanol-ethanol (ABE) fermentation has recently gained renewed interest in the context of biorefinery approaches for the production of fuels and chemicals from renewable resources. The availability of new methods and knowledge opens many new doors for industrial microbiology, and a comprehensive view on this process is worthwhile due to the new interest. This thematic issue of FEMS Microbiology Letters, dedicated to the 100th anniversary of the first industrial exploitation of Chaim Weizmann's ABE fermentation process, covers the main aspects of old and new developments, thereby outlining a model development in biotechnology. All major aspects of industrial microbiology are exemplified by this single process. This includes new technologies, such as the latest developments in metabolic engineering, the exploitation of biodiversity and discoveries of new regulatory systems such as for microbial stress tolerance, as well as technological aspects, such as bio- and down-stream processing.

Economic comparison of a continuous ABE fermentation with and without the integration of an in situ vacuum separation unit

The development of renewable fuels has achieved enormous progress motivated by the rapid decline in petroleum resources and their oscillating price. After a wave of interest in bioethanol and biodiesel, biobutanol has been intensely investigated over the last decade and is considered a suitable renewable fuel. Biobutanol is most often produced through the Acetone‐Butanol‐Ethanol (ABE) bacterial fermentation process. This process is plagued, however, with high recovery costs because of the low final butanol concentration (∼0.01 g/g, 1 wt %) due to product inhibition on the microorganisms. To partly alleviate this problem and increase productivity, in situ butanol recovery techniques from the fermentation broth were proposed. These integrated methods increase the final concentration of butanol, and as a result improve the separation efficiency of the process. This paper compares the economic feasibility of a large‐scale continuous ABE fermentation process with and without integrating a vacuum separation unit. It is illustrated that based on the current market price of butanol, only the integrated fermentation process is economically feasible for discount rates up to ∼45 %. Adding an in situ butanol recovery technique made this process profitable compared to the conventional fermentation process analyzed under two different scenarios: constant fermenter volume and constant butanol production rate. The net present values (NPV) of the conventional process were found to be negative for both scenarios, whereas the integrated vacuum process had a NPV of US$ 87 000 000 at the end of 10 years of operation based on a discount rate of 10 %.

Improved SI engine efficiency using Acetone–Butanol–Ethanol (ABE)

Alcohols, especially n-butanol, have received a lot of attention as potential fuels and have shown to be a possible alternative to pure gasoline. The main issue preventing butanol’s use in modern engines is its relatively high cost of production. ABE, the intermediate product in the ABE fermentation process for producing bio-butanol, is being studied as an alternative fuel because it not only preserves the advantages of oxygenated fuels, but also lowers the cost of fuel recovery for individual component during fermentation. With the development of advanced ABE fermentation technology, the volumetric percentage of acetone, butanol and ethanol in the bio-solvents can be precisely controlled. In this respect, it is desirable to estimate the performance of different ABE blends to determine the best blend and optimize the production process accordingly. In this paper, pure ABE fuels with different component volumetric ratio, (A:B:E of 3:6:1, 6:3:1 and 5:14:1), were combusted in a naturally aspirated, port-fuel injected spark ignited engine. The performance of these blends was evaluated through measurements of in-cylinder pressure, and various exhaust emissions. In addition, pure gasoline and neat n-butanol were also tested as baselines for comparison of ABE fuels. The tests were conducted at an engine speed of 1200RPM and loads of 3 and 5bar brake mean effective pressure (BMEP) under different equivalence ratios. On the basis of the experimental data, the combustion characteristics and emission behavior of these fuels have been presented and discussed. It was found that in terms of thermal efficiency, ABE(6:3:1) might be much better suited for use as an alternative fuel, relative to ABE(3:6:1) or n-butanol.

Iron effect on the fermentative metabolism of Clostridium acetobutylicum ATCC 824 using cheese whey as substrate

Butanol is considered a superior liquid fuel that can replace gasoline in internal combustion engines. It is produced by acetone-butanol-ethanol (ABE) fermentation using various species of solventogenic clostridia. Performance of ABE fermentation process is severely limited mostly by high cost of substrate, substrate inhibition and low solvent tolerance; leading to low product concentrations, low productivity, low yield, and difficulty in controlling culture metabolism. In order to decrease the cost per substrate and exploit a waste generated by dairy industry, this study proposes using cheese whey as substrate for ABE fermentation. It was observed that the addition of an iron source was strictly necessary for the cheese whey to be a viable substrate because this metal is needed to produce ferredoxin, a key protein in the fermentative metabolism of Clostridium acetobutylicum serving as a temporary electron acceptor. Lack of iron in the cheese whey impedes ferredoxin synthesis and therefore, restricts pyruvate-ferredoxin oxidoreductase activity leading to the production of lactic acid instead of acetone, butanol and ethanol. Moreover, the addition of FeSO4 notably improved ABE production performance by increasing butanol content (7.13 ± 1.53 g/L) by 65% compared to that of FeCl3 (4.32 ± 0.94 g/L) under the same fermentation conditions.