Acetone, Butanol And Ethanol Fermentation Research Articles

OPTIMIZATION AND QUALITY ANALYSIS OF BIO-BUTANOL PRODUCTION FROM SUGARCANE (Saccharum officinarum) BAGASSE HYDROLYSATE

Several companies are currently investigating in development for the production of Biobutanol. This research was concerned with Biobutanol production from ABE (Acetone, Butanol, and Ethanol) fermentation of sugarcane bagasse hydrolysate by Clostridium Perfringens. The sample was hydrolyzed with concentrated H2SO4 solution for 1 hour at 121oC. Response surface designed by optimizing the fermentation parameters (Time, Temperature, and pH) by the used media (C. Perfringens) showed the highest Biobutanol yield at temperature (350C), Time 48 (Hhs), and pH 6.0 with 163 cm3 which is exactly around 0.543(g/L) by converted to a gram per liter as mostly represented by many researchers. The produced Biobutanol from the sugarcane bagasse hydrolysate was characterized using FT-IR and GC-MS analysis. Conclusively this work revealed the importance of sugarcane bagasse as a good potential feedstock of Biobutanol.

Changes in efflux pump activity of Clostridium beijerinckii throughout ABE fermentation

Pumping toxic substances through a cytoplasmic membrane by protein transporters known as efflux pumps represents one bacterial mechanism involved in the stress response to the presence of toxic compounds. The active efflux might also take part in exporting low-molecular-weight alcohols produced by intrinsic cell metabolism; in the case of solventogenic clostridia, predominantly acetone, butanol and ethanol (ABE). However, little is known about this active efflux, even though some evidence exists that membrane pumps might be involved in solvent tolerance. In this study, we investigated changes in overall active efflux during ABE fermentation, employing a flow cytometric protocol adjusted for Clostridia and using ethidium bromide (EB) as a fluorescence marker for quantification of direct efflux. A fluctuation in efflux during the course of standard ABE fermentation was observed, with a maximum reached during late acidogenesis, a high efflux rate during early and mid-solventogenesis and an apparent decrease in EB efflux rate in late solventogenesis. The fluctuation in efflux activity was in accordance with transcriptomic data obtained for various membrane exporters in a former study. Surprisingly, under altered cultivation conditions, when solvent production was attenuated, and extended acidogenesis was promoted, stable low efflux activity was reached after an initial peak that appeared in the stage comparable to standard ABE fermentation. This study confirmed that efflux pump activity is not constant during ABE fermentation and suggests that undisturbed solvent production might be a trigger for activation of pumps involved in solvent efflux. KEY POINTS: • Flow cytometric assay for efflux quantification in Clostridia was established. • Efflux rate peaked in late acidogenesis and in early solventogenesis. • Impaired solventogenesis led to an overall decrease in efflux.

Enhanced butanol production by Clostridium acetobutylicum fermentation using thermo‐responsive poly(N‐isopropylacrylamide)‐grafted PDMS sponge as adsorbent material

AbstractBACKGROUNDButanol production through ABE (acetone, butanol, and ethanol) fermentation has attracted a great deal of attention because of its potential to replace petroleum‐based fuels. Low butanol production and productivity due to butanol inhibition are the main challenges to make ABE fermentation viable economically. In this work, polydimethylsiloxane (PDMS) sponge and thermos‐responsive poly(N‐isopropylacrylamide)‐grafted PDMS (PNIPAAm‐PDMS) sponges (with different mass fractions of PNIPAAm on the PDMS surface) were investigated as adsorbents for butanol.RESULTSThe butanol model solutions showed that the adsorption–desorption efficiency of different types of sponges for butanol is highly temperature‐dependent. Higher temperatures exhibited higher adsorption efficiency. In contrast, lower temperatures markedly increased the desorption efficiency for butanol. PNIPAAm‐PDMS with 8.0 wt% of PNIPAAm on the PDMS surface showed as the best adsorbent for butanol. It had adsorption efficiency of 14, 24 and 46% at 25, 37 and 50 °C, respectively. Moreover, 96% of butanol adsorbed was recovered at 25 °C. When it was coupled with a batch ABE fermentation by Clostridium acetobutylicum, butanol production increased by 102% compared to batch fermentation without adsorption. A semi‐continuous fermentation with the initial feeding time at the 60th hour exhibited as the optimum condition. However, it failed to enhance butanol productivity due to a high accumulation of butanol in the broth. Then, a semi‐continuous fermentation with adsorption was conducted, yielding total butanol production of 20 g/L.CONCLUSIONPNIPAAm‐PDMS sponge is proposed as an adsorbent to overcome butanol inhibition in ABE fermentation by temperature manipulation to recover butanol. © 2019 Society of Chemical Industry

Towards comprehensive lignocellulosic biomass utilization for bioenergy production: Efficient biobutanol production from acetic acid pretreated switchgrass with Clostridium saccharoperbutylacetonicum N1-4

For bioenergy production from lignocellulosic biomass, most biomass pretreatment processes need to use some chemical reagent as the catalyst to overcome the biomass recalcitrance barrier. Such reagents are usually severe inhibitors for the subsequent microbial fermentation process. Therefore, in many cases, the liquid prehydrolysates fraction (LPF) is discarded after the pretreatment, which is a tremendous waste of materials and leads to additional pollution. Biobutanol produced from the acetone, butanol and ethanol (ABE) fermentation process has been of great interests recently due to its high value as a bioenergy source or biochemical. During ABE fermentation, acetic acid (AA) is produced and then re-assimilated as a carbon source. Thus, AA is a substrate rather than an inhibitor for biobutanol production. In this study, we employed AA as the chemical catalyst for the pretreatment of switchgrass which then be used for ABE production through simultaneous saccharification and fermentation (SSF) with hyper-butanol producing Clostridium saccharoperbutylacetonicum N1-4. Through systematic investigation of the pretreatment conditions and fermentation, we concluded that the optimized condition for switchgrass pretreatment was with 3 g/L AA at 170 °C for 20 min. Both LPF and solid cellulosic fraction (SCF) of the pretreated biomass were highly fermentable. In the fermentation with the SCF/LPF mixture as the substrate, 8.6 g/L butanol (corresponding to a yield of 0.16 g/g) was obtained. Overall, here we demonstrated an innovative and tailored biomass pretreatment strategy for comprehensive and efficient carbon source utilization for bioenergy production.

Zeolite MFI adsorbent for recovery of butanol from ABE fermentation broths produced from an inexpensive black liquor-derived hydrolyzate

In this work, high-silica MFI zeolite adsorbent was evaluated for selective recovery of butanol from a real ABE (acetone, butanol, and ethanol) fermentation broth by batch adsorption measurements. The fermentation broth was produced using a hydrolyzate originating from Kraft black liquor, an internal stream in pulp mills, i.e., a low-cost substrate. The adsorbent was very selective towards butanol and butyric acid and became nearly saturated with a mixture of butanol and butyric acid with relative amounts of butanol and butyric acid depending on the pH. The presence of phenolic compounds in significant amounts in the fermentation broths, originating from the black liquor hydrolyzate, did not affect the adsorption of butanol and butyric acid.

Effects of Tween 80 on fermentative butanol production from alkali-pretreated switchgrass

In this study, switchgrass was investigated as a renewable feedstock for fermentative production of acetone, butanol and ethanol (ABE). For this purpose, switchgrass was first subjected to alkaline pretreatment, which reduces its recalcitrance and increases enzyme accessibility. Both simultaneous saccharification and fermentation (SSF) and separate hydrolysis and fermentation (SHF) were applied. The pretreated switchgrass solids inhibit ABE fermentation, presumably due to the residual lignin portion, as evidenced by the toxicity test of various model phenolic compounds. Addition of a non-ionic surfactant, Tween 80, alleviated the phenol-induced inhibition. As constrained by the “solid effects”, the upper limit of solid loading that SSF could process was in the range of 5–6%. SSF with 5% solid loading produced a total of 12.3 g/L ABE solvents with 7.8 g/L of butanol. SHF was further applied to process higher solid loadings. A total of 14.3 g/L ABE solvent with 8.5 g/L of butanol was produced from SHF with 7% solid loading. SSF gave an overall bioconversion yield close to that of pure sugar control, whereas SHF was able to avoid the “solid effects” with a slightly lower overall bioconversion yield.

Life cycle assessment of butanol production

The goal of this work was to analyse and compare the environmental impacts of three production methods of butanol. The first one is based on the oxo synthesis and the others use ABE (acetone, butanol and ethanol) fermentation. A life cycle assessment for all alternatives under study was carried out. The ABE fermentation using corn as substrate presents the highest environmental impact and the ABE fermentation using wheat straw is the one that presents the lowest environmental impact, when the allocation method was based on mass. Considering an economic allocation method, the relative weight of butanol raised which increased considerably the environmental impact value in ABE processes due to the lower economic value of gases.A sensitivity analysis was performed for the production of butanol from the two ABE processes varying the data of lower quality to analyse how this would affect the environmental impacts. In the ABE process with wheat straw the variations performed within the scope of the sensibility analysis had no meaningful effect in the global impact (<4.0%) except when the production of gases was varied. In this case the reduction of 50% in the mass of gases produced could result in an increase of roughly 40% in the global impact. For the ABE process with the corn the variation of wastewater produced resulted in a decrease of global environmental impact lower than 1%.

Butanol production from lignocellulose by simultaneous fermentation, saccharification, and pervaporation or vacuum evaporation

Techno-economic study of acetone, butanol and ethanol (ABE) fermentation from lignocellulose was performed. Simultaneous saccharification, fermentation and vacuum evaporation (SFS-V) or pervaporation (SFS-P) were proposed. A kinetic model of metabolic pathways for ABE fermentation with the effect of phenolics and furans in the growth was proposed based on published laboratory results. The processes were optimized in Matlab®. The end ABE purification was carried out by heat-integrated distillation. The objective function of the minimization was the total annualized cost (TAC). Fuel consumption of SFS-P using poly[1-(trimethylsilyl)-1-propyne] membrane was between 13.8 and 19.6% lower than SFS-V. Recovery of furans and phenolics for the hybrid reactors was difficult for its high boiling point. TAC of SFS-P was increased 1.9 times with supplementation of phenolics and furans to 3g/l each one for its high toxicity. Therefore, an additional detoxification method or an efficient pretreatment process will be necessary.

Development of an inducible transposon system for efficient random mutagenesis in Clostridium acetobutylicum.

Clostridium acetobutylicum is an industrially important Gram-positive organism, which is capable of producing economically important chemicals in the ABE (Acetone, Butanol and Ethanol) fermentation process. Renewed interests in the ABE process necessitate the availability of additional genetics tools to facilitate the derivation of a greater understanding of the underlying metabolic and regulatory control processes in operation through forward genetic strategies. In this study, a xylose inducible, mariner-based, transposon system was developed and shown to allow high-efficient random mutagenesis in the model strain ATCC 824. Of the thiamphenicol resistant colonies obtained, 91.9% were shown to be due to successful transposition of the catP-based mini-transposon element. Phenotypic screening of 200 transposon clones revealed a sporulation-defective clone with an insertion in spo0A, thereby demonstrating that this inducible transposon system can be used for forward genetic studies in C. acetobutylicum.

Erratum to: Recovery of butanol from model ABE fermentation broths using MFI adsorbent: a comparison between traditional beads and a structured adsorbent in the form of a film

Butanol, a promising biofuel, can be produced by ABE (acetone, butanol and ethanol) fermentation using e.g. Clostridium acetobutylicum. However, the butanol concentration in the resulting broth is limited to only ca. 20 g/L due to the toxicity for the microorganisms. This low product concentration demands an efficient recovery process for successful commercialization of this process. In this study, a structured adsorbent in the form of steel monolith coated with a silicalite-1 film was prepared using the in situ growth method. The adsorbent was carefully characterized by SEM and XRD. The performance of the adsorbent was evaluated by performing breakthrough experiments at room temperature using model ABE fermentation broths and the performance was compared with that of traditional adsorbents in the form of beads. The structured silicalite-1 adsorbent showed less saturation loading time as compared to commercial binder free silicalite-1 beads, reflecting the different dimensions of the columns used, set by experimental constraints. Studies of the desorption process showed that by operating at appropriate conditions, butanol with high concentration i.e. up to 95.2 wt% for butanol–water model system and 88.5 wt% for ABE fermentation broth can be obtained using the structured silicalite-1 adsorbent. Commercial silicalite-1 beads also showed good selectivity but the concentration of butanol in the desorbed product was limited to 70 % for the butanol–water model system and 69 % for ABE fermentation broth, probably as a result of entrained liquid between the beads.

Butanol production under microaerobic conditions with a symbiotic system of Clostridium acetobutylicum and Bacillus cereus

BackgroundOne major problem of ABE (acetone, butanol and ethanol) fermentation is high oxygen sensitivity of Clostridium acetobutylicum. Currently, no single strain has been isolated or genetically engineered to produce butanol effectively under aerobic conditions. In our previous work, a symbiotic system TSH06 has been developed successfully by our group, and two strains, C. acetobutylicum TSH1 and Bacillus cereus TSH2, were isolated from TSH06.ResultsCompared with single culture, TSH06 showed promotion on cell growth and solvent accumulation under microaerobic conditions. To simulate TSH06, a new symbiotic system was successfully re-constructed by adding living cells of B. cereus TSH2 into C. acetobutylicum TSH1 cultures. During the fermentation process, the function of B. cereus TSH2 was found to deplete oxygen and provide anaerobic environment for C. acetobutylicum TSH1. Furthermore, inoculation ratio of C. acetobutylicum TSH1 and B. cereus TSH2 affected butanol production. In a batch fermentation with optimized inoculation ratio of 5 % C. acetobutylicum TSH1 and 0.5 % B. cereus TSH2, 11.0 g/L butanol and 18.1 g/L ABE were produced under microaerobic static condition. In contrast to the single culture of C. acetobutylicum TSH1, the symbiotic system became more aerotolerant and was able to produce 11.2 g/L butanol in a 5 L bioreactor even with continuous 0.15 L/min air sparging. In addition, qPCR assay demonstrated that the abundance of B. cereus TSH2 increased quickly at first and then decreased sharply to lower than 1 %, whereas C. acetobutylicum TSH1 accounted for more than 99 % of the whole population in solventogenic phase.ConclusionsThe characterization of a novel symbiotic system on butanol fermentation was studied. The new symbiotic system re-constructed by co-culture of C. acetobutylicum TSH1 and B. cereus TSH2 showed excellent performance on butanol production under microaerobic conditions. B. cereus TSH2 was a good partner for C. acetobutylicum TSH1 by providing an anaerobic environment. During fermentation process, the high ratio of Clostridium and low ratio of Bacillus composition indicated that this symbiotic system was an effective and easily controlled cultivation model for ABE fermentation under microaerobic conditions.

Butanol production from corncob residue using Clostridium beijerinckii NCIMB 8052

To determine whether corncob residue (CCR) could be a good substrate for butanol production. In this study, Ca(OH)₂ detoxification technique was used to remove inhibitors of lignocellulose enzymatic hydrolysis. During fermentation of untreated corncob residue hydrolysate (CCRH) by Clostridium beijerinckii NCIMB 8052, cell growth was inhibited and only 3·8 g l⁻¹ acetone, butanol and ethanol (ABE) was produced. After pretreatment with Ca(OH)₂, enzymatic hydrolysis of CCR resulted in 49·3 g l⁻¹ total sugars, about twofold of that of untreated one. In the fermentation of the Ca(OH)₂-detoxified CCRH, sugar utilization ratio was increased by 27·3%. When using the Ca(OH)₂-detoxified CCRH supplemented with 10 g l⁻¹ glucose, 16·0 g l⁻¹ ABE was produced, resulting in an ABE yield of 0·32 and a productivity of 0·33 g l⁻¹ h⁻¹. The results in this study suggest that CCR was a good carbon source for ABE fermentation. It is the first time to use CCR as substrate for butanol production. Ca(OH)₂ detoxification pretreatment was proved to be an effective method to improve enzymatic digestibility of lignocellulose.

Improvement in the bioreactor specific productivity by coupling continuous reactor with repeated fed-batch reactor for acetone–butanol–ethanol production

In comparison to the different fermentation modes for the production of acetone, butanol and ethanol (ABE) researched to date, the continuous fermentation is the most economically favored. Continuous fermentation with two or more reactor cascade is reported to be the most efficient as it results in a more stable solvent production process. In this work, it is shown that a continuous (first-stage) reactor coupled to a repeated fed-batch (second stage) is superior to batch and fed-batch fermentations, including two-stage continuous fermentation. This is due to the efficient catalyst use, reported through the specific product rate and rapid glucose consumption rate. High solvents are produced at 19.4 g(ABE) l⁻¹, with volumetric productivities of 0.92 g(butanol) l⁻¹ h⁻¹ and 1.47 g(ABE) l ⁻¹ h⁻¹. The bioreactor specific productivities of 0.62 and 0.39 g g⁻¹(cdw) h⁻¹ obtained show a high catalyst activity. This new process mode has not been reported before in the development of ABE fermentation and it shows great potential and superiority to the existing fermentation methods.

Butanol production by Clostridium beijerinckii ATCC 55025 from wheat bran

Wheat bran, a by-product of the wheat milling industry, consists mainly of hemicellulose, starch and protein. In this study, the hydrolysate of wheat bran pretreated with dilute sulfuric acid was used as a substrate to produce ABE (acetone, butanol and ethanol) using Clostridium beijerinckii ATCC 55025. The wheat bran hydrolysate contained 53.1 g/l total reducing sugars, including 21.3 g/l of glucose, 17.4 g/l of xylose and 10.6 g/l of arabinose. C. beijerinckii ATCC 55025 can utilize hexose and pentose simultaneously in the hydrolysate to produce ABE. After 72 h of fermentation, the total ABE in the system was 11.8 g/l, of which acetone, butanol and ethanol were 2.2, 8.8 and 0.8 g/l, respectively. The fermentation resulted in an ABE yield of 0.32 and productivity of 0.16 g l(-1) h(-1). This study suggests that wheat bran can be a potential renewable resource for ABE fermentation.

Utilisation of saccharides in extruded domestic organic waste by Clostridium acetobutylicum ATCC 824 for production of acetone, butanol and ethanol.

Domestic organic waste (DOW) collected in The Netherlands was analysed and used as substrate for acetone, butanol and ethanol (ABE) production. Two different samples of DOW, referred to as fresh DOW and dried DOW, were treated by extrusion in order to expand the polymer fibres present and to obtain a homogeneous mixture. The extruded material was analysed with respect to solvent and hot water extractives, uronic acids, lignin, sugars and ash. The total sugar content in the polymeric fractions of the materials varied from 27.7% to 39.3% (w/w), in which glucose represented the 18.4 and 25.1% of the materials, for fresh and dried DOW, respectively. The extruded fresh DOW was used as substrate for the ABE fermentation by the solventogenic strain Clostridium acetobutylicum ATCC 824. This strain was grown on a suspension of 10% (w/v) DOW in demineralised water without further nutrient supplement. This strain produced 4 g ABE/100 g extruded DOW. When C. acetobutylicum ATCC 824 was grown on a suspension of 10% (w/v) DOW hydrolysed by a combination of commercial cellulases and beta-glucosidases, the yield of solvents increased to 7.5 g ABE/100 g extruded DOW. The utilisation of sugar polymers in both hydrolysed and non-hydrolysed DOW was determined, showing that only a small proportion of the polymers had been consumed by the bacteria. These results indicate that growth and ABE production on DOW is mainly supported by soluble saccharides in the medium.