Butyl Butyrate Research Articles

RESEARCH OF VARIOUS ISO-MANIFOLDS IN FOUR COMPONENT SYSTEMS CONTAINING BIAZEOTROPIC BINARY CONSTITUENTS

In the present work, an analysis of the mutual arrangement of a number of iso-manifolds in the concentration tetrahedron formed by the components of the separated mixture and an additional substance, an extractive agent, was carried out to estimate the possibility of separating three-component mixtures containing biazeotropic constituents by extractive rectification. The objects of research were four-component systems formed by ternary constituents (butyl propionate (BP) - propionic acid (PA) - butyl butyrate (BB), butyl propionate - propionic acid - butyric acid (BA), butyl butyrate - butyric acid -butyl propionate, butyl butyrate - butyric acid -propionic acid) of the commercially important BP-PA-BB-BA system, and the extractive agent sulfolane. Using the results of the computational experiment based on mathematical model NRTL-HOC we obtained complete data on the vapor-liquid equilibrium in binary, three- and four-component systems. The structures of liquid-vapor phase diagrams were obtained, and thermodynamic-topological analysis of all four-component systems was carried out. The mutual arrangement in the concentration tetrahedron of manifolds of relative volatility (equal to 1) of the components, reflecting the evolution of pseudo-azeotropes in sections with a constant concentration of the extractive agent; pseudo-ideal manifolds along which the activity coefficients of the components of the base (separated) mixture are equal to each other; isothermo-isobaric manifolds generated by Bancroft points in binary azeotropic constituents were determined. We established that it is possible to separate the studied three-component mixtures by extractive rectification using sulfolane.

Comparison of Esterifying Ability of Some Lipases

The esterification activity of some commercial lipases was examined. The comparison of the enzymatic activities was carried out in regard to the synthesis of esters of lower aliphatic acids and alcohols. The highest esterifying ability was shown by the enzyme preparation Novozym 435 which quickly starts the process. The conversion of used acids was 70 - 82% within 0.5 hours, and reached 90% of conversion in 1 hour of reaction. Similar efficacy shows Novozym 40086. This enzyme preparation provides 90% conversion of the acids in two hours of process. The enzyme preparation Lipozyme TLIM provides conversion of the used acids on 84 – 90% in three hours of process. The enzyme preparation Lipozyme CALB is less effective on the used acids. Thus, in the synthesis of aliphatic esters the esterifying ability of enzyme preparations in the studied conditions decreases in a row: Novozym 435, Novozym 40086, Lipozyme TLIM, Lipozyme CALB. Pancreatic lipase in the synthesis of butyl butyrate detects an induction period of about 1 hour.<div><br></div>

Analysis of Butyl Butyrate Mass Spectrum

The aim of this educational work is targeting chemistry students and interested instructors. The presented work will analyze the mass spectrum of butyl butyrate (butyl butanoate). The analysis will concentrate on the mechanisms showing how the characteristic fragments are formed. The mechanisms discussed in this paper include α-cleavage, β-cleavage, McLafferty Rearrangements, first and second proton transfer, a double proton transfer.

Features of injection and chromatographic separation of samples in high boiling viscous organic solvents using the capillary columns at a low split ratio

The features of injection and gas chromatographic separation of stock analytes in their solutions in high boiling viscous polar organic solvents (on the example of 1,3-butanediol) using a short capillary column of large internal diameter (Megabore type) at low split ratios are considered. The manifestation of so-called discrimination effects is confirmed, with the main of them being the dependence of absolute peak areas vs . injection temperature as well as similar dependence of relative peak areas in different solvents. However, these effects are manifested in a lesser degree than the same effects for the samples dissolved in low boiling solvents. It is demonstrated that the dependencies of peak areas vs . injector temperature ( S = aT + b ) are principally different for solvents with various boiling points. Thus, for the solutions of butyl acetate, cyclohexanone, anisol, butyl butyrate, and acetophenone in low boiling 2-propanol the linear dependencies S ( T ) are revealed for the injector temperature range of 120-180°С only (with correlation coefficients r = 0.986 – 0.999), while at the higher injector temperatures (210-240°С) the significant deviations from linearity are typical. At the same time, the solutions of the same components in higher boiling 1,3-butanediol demonstrate the linear S ( T ) dependencies within the whole temperature range (120-240°С). It is confirmed that the discrimination effects have no significant influence on the results of gas chromatographic analyses of the samples in high boiling solvents if the method of internal normalization is used. The main uncertainties of the results are caused by the column’s overloading with the solvent, which leads to the broadening and asymmetry of its peaks and their overlapping with the peaks of some analytes. DOI: http://dx.doi.org/10.15826/analitika.2018.22.3.005 Keywords : High boiling viscous organic solvents, gas chromatographic analysis, capillary columns, discrimination effects (Russian) Igor G. Zenkevich, Eugene Leleev St. Petersburg State University, Russian Federation, 198504, St. Petersburg, Universitetskii prosp., 26

DESAROLLO DE UN BIORREACTOR COMPUESTO POR LIPASA ATRAPADA EN UN CRIOGEL MONOLÍTICO PARA LAS REACCIONES DE ESTERIFICACIÓN E INTERESTERIFICACIÓN

In this work, it was developed novel bioreactor consisting of Aspergillus niger lipase (ANL) entrapped in a polyacrylamide-based supermacroporous monolithic cryogel. Bioreactor performance in catalyzing the flavor ester butyl butyrate was optimized as a function of temperature (°C), substrate molar ratio (butyric acid: n-butanol) and added water (% (v/v)). The bioreactor was also applied to interesterification reactions. The maximum esterification yield (46%) for butyl butyrate synthesis was found at 40 °C, with a butyric acid:n-butanol molar ratio of 1:1.43 and added water of 65% (v/v). The bioreactor proved to be reusable with four consecutive reuses in the esterification reaction, with a residual esterification yield of 64.6% and volumetric activity of 31.6 mmol/mL·h. A high interesterification yield (17.35% in 24 h) was achieved when the substrate concentrations of tripalmitin and triolein were both 15 mmol/L, 35% added water (v/v) and temperature of 40 °C. These results showed that the bioreactor is a promising biocatalyst for biotechnological applications.

In Situ Biocatalytic Synthesis of Butyl Butyrate in Diesel and Engine Evaluations

AbstractBlending petroleum fuels with biofuels is likely to become increasingly important over the years to come. Butyl butyrate has promising characteristics as a blend component in diesel and can be synthesized by lipase‐catalyzed esterification of 1‐butanol and butyric acid, which both can be derived from fermentation technologies. In the current study, the enzyme load and reaction temperature were optimized for the production of butyl butyrate with Novozyme 435 (immobilized Candida antarctica lipase B) directly in diesel at a substrate concentration of 1 m using a molar ratio of 1:1 between n‐butanol and butyric acid. Optimum conditions were found by using a central composite design at an enzyme load of 12 % of substrate weight and a temperature of 57 °C, giving 90 % yield conversion in 30 min, corresponding to a butyl butyrate productivity of 1.8 mol L−1 h−1. Diesel blended with 5, 10, and 30 % butyl butyrate was tested in a heavy‐duty diesel engine under two load cases. The ignition properties of the blended fuels were very similar to pure diesel, making butyl butyrate an interesting diesel substitute. The emission analysis demonstrated lower soot and CO emissions, similar hydrocarbons levels and slightly increased NOx levels compared with using pure diesel. The high activity of lipase in diesel and the compatibility between diesel and butyl butyrate opens up the possibility to develop fuel blending systems where the synthesis of the blend‐in component occurs directly in the fuel.

A STATISTICAL APPROACH FOR OPTIMIZING THE HIGH YIELD GREEN PRODUCTION OF THE FLAVOR ESTER BUTYL BUTYRATE

Being the prevailing approach for producing esters such as butyl butyrate, the use of chemical route has been linked to numerous disadvantages. Hence, a green alternative method for higher yield production of butyl butyrate by esterification reaction utilizing Novozyme 435 as biocatalysts in a solvent-less system may prove useful. Such approach can be further improved by optimizing the relevant reaction parameters using the Response Surface Methodology by the Box-Benkhen Design attempted in this present study. The reaction parameters evaluated were: substrate molar ratio, time and temperature, and the response of each parameter was measured as percentage conversion yield. Using the Design Expert 7.1.6 optimization functions, the two sets of optimum conditions selected viz. [i] molar ratio butyric acid:butanol 1:3.93, 9.93 h at 56.09°C and [ii] molar ratio butyric acid:butanol 1:3.35, 9.79 h at 53.90°C had afforded the highest yield of butyl butyrate i.e. 99.62% and 99.55%, respectively. The ester product obtained from the reaction were confirmed as butyl butyrate by FTIR and GC. Therefore, the results substantiated the applicability of the RSM prediction technique as well as efficacy of Novozyme 435 as biocatalysts in the high yield solvent-less synthesis of butyl butyrate, adhering to the philosophy of Green Chemistry.

High-level expression and characterization of a novel cutinase from Malbranchea cinnamomea suitable for butyl butyrate production

BackgroundButyl butyrate has been considered as a promising fuel source because it is a kind of natural ester which can be converted from renewable and sustainable lignocellulosic biomass. Compared with the conventional chemical methods for butyl butyrate production, the enzymatic approach has been demonstrated to be more attractive, mainly owing to the mild reaction conditions, high specificity, low energy consumption, and environmental friendliness. Cutinases play an important role in the butyl butyrate production process. However, the production level of cutinases is still relatively low. Thus, to identify novel cutinases suitable for butyl butyrate synthesis and enhance their yields is of great value in biofuel industry.ResultsA novel cutinase gene (McCut) was cloned from a thermophilic fungus Malbranchea cinnamomea and expressed in Pichia pastoris. The highest cutinase activity of 12, 536 U/mL was achieved in 5-L fermentor, which is by far the highest production for a cutinase. McCut was optimally active at pH 8.0 and 45 °C. It exhibited excellent stability within the pH range of 3.0–10.5 and up to 75 °C. The cutinase displayed broad substrate specificity with the highest activity towards p-nitrophenyl butyrate and tributyrin. It was capable of hydrolyzing cutin, polycaprolactone, and poly(butylene succinate). Moreover, McCut efficiently synthesized butyl butyrate with a maximum esterification efficiency of 96.9% at 4 h. The overall structure of McCut was resolved as a typical α/β-hydrolase fold. The structural differences between McCut and Aspergillus oryzae cutinase in groove and loop provide valuable information for redesign of McCut. These excellent features make it useful in biosynthesis and biodegradation fields.ConclusionsA novel cutinase from M. cinnamomea was identified and characterized for the first time. High-level expression by P. pastoris is by far the highest for a cutinase. The enzyme exhibited excellent stability and high esterification efficiency for butyl butyrate production, which may make it a good candidate in biofuel and chemical industries.

Structure and properties of oil palm-based nanocellulose reinforced chitosan nanocomposite for efficient synthesis of butyl butyrate

In this study, nanocellulose (NC) was successfully extracted from oil palm frond leaves (OPFL) using a combination of bleaching, alkaline treatment and acid hydrolysis. X-ray diffractogram revealed the extracted NC was crystalline with a crystallinity index of 70.2%. This indicates its suitability as nano-fillers for preparing the chitosan/nanocellulose (CS-NC) supports to immobilize Candida rugosa lipase (CRL) to produce the CRL/CS-NC biocatalysts. FTIR, FESEM and TGA characterizations of the CRL/CS-NC confirm the CRLs were successfully conjugated to the CS-NC supports. The air-dried CS-NC supports gave satisfactory immobilization of the CRLs (5.2mg/g) with the resultant CRL/CS-NCs catalysed conversions of ≥80% of butyl butyrate within 6h. Time course reaction profile revealed that 76.3% butyl butyrate conversion was achieved at 4h immobilization time using 3mg/mL of CRL/CS-NCs. NMR analyses on the purified butyl butyrate confirmed that the ester was successfully synthesized.

Analysis of volatile compounds as quality indicators for Fuji apples after cold storage

Changes in the volatile components in Fuji apples were investigated by the analysis of intact apples using headspace solid-phase microextraction–gas chromatography–mass spectrometry to assess their quality during long-term storage at 4°C (3, 6, and 9 months). Three alcohols and 28 esters were identified, and the feeding of precursor alcohols (e.g., butanol, hexanol, and 2-methylbutanol) resulted in significantly increased amounts of eight esters. Among these esters, the peak area ratios (PARs) of butyl acetate, butyl butanoate, butyl 2-methylbutanotate, or 2-methylbutyl acetate to the eight esters were highly correlated with those of their precursor alcohols to the total alcohol content (R2 ≥ .9253). In addition, the PAR of precursor alcohols to the total alcohol content, as well as the PAR of these esters to the eight esters, significantly increased during storage at 4°C (p < .01). Therefore, it is concluded that PARs can be used as quality indicators for Fuji apples. Practical applications Quality assessment is crucial in the food industry to maintain food quality. An accurate, rapid method must be available for an assessment of quality. In addition, the identification of reliable biomarkers is imperative for quality assessment. Because of their versatility, volatile compounds in foods can provide considerable information about the quality of foods. In this study, volatile compounds in Fuji apples served as good quality indicators, and these apples were nondestructively analyzed without sample treatment. In addition, multiple volatile indicators were identified and validated. The results suggested that the volatile compounds analyzed by this nondestructive method can serve as indicators for the rapid, robust assessment of the quality of Fuji apples in the agricultural industry.

Determination of volatile compounds by headspace-solid phase microextraction - gas chromatography / mass spectrometry: Quality evaluation of Fuji apple

The volatile components in 'Fuji' apple were effectively determined by a headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). A total of 48 volatile components were identified and tentatively characterized based on National Institute of Standards and Technology (NIST) MS spectra library and the Kovats GC retention index I (RI). The harvested Fuji apples were divided into two groups: 1-methylcyclopropene (1-MCP) treated and non-treated (control) samples for finding important indicators between two groups. The major volatile components of both apples were 2-methylbutyl acetate, hexyl acetate, butyl 2-methylbutanoate, hexyl butanoate, hexyl 2-methylbutanoate, hexyl hexanoate and farnesene. No significant differences of these major compounds between 1-MCP treated and non-treated apples were observed during 1 month storage. Interestingly, the amount of off-flavors, including 1-butanol and butyl butanoate, in 1-MCP treated apples decreased over 5 months, and then increased after 7 months. However, non-treated apples did not show significant changes for off-flavors during 7 month storage (p<0.05). The non-treated apples also contained the higher levels of two off-flavors than 1-MCP treated apples. These two compounds, 1-butanol and butyl butanoate, can be used as quality indicators for the quality evaluation of Fuji apple.

The effects of Ficus carica on the activity of enzymes related to metabolic syndrome

The present study aimed to investigate the effects of the various parts of Ficus carica L. (figs) on antioxidant, antidiabetic, and antiobesogenic effects in vitro. Fruit, leaves, and stembark of the F. carica plant were sequentially extracted using organic and inorganic solvents and their total polyphenol and flavonoid contents were estimated. The effects of the extracts on antioxidative, antidiabetic (inhibition of α-amylase and α-glucosidase enzymes), and antiobesogenic (antilipase) activities were measured using several experimental models. The fruit ethanolic extract contained a high quantity of polyphenols and flavonoids (104.67±5.51 μg/mL and 81.67±4.00 μg/mL) compared with all other extracts. The activity of the ethanolic extract of F. carica fruit was significantly (p<0.05) higher than all other extracts and parts of the plant in terms of antioxidative, antidiabetic, and antiobesogenic effects. The IC50 values of the fruit ethanolic extract in terms of antioxidative (134.44±18.43 μg/mL), and inhibition of α-glucosidase (255.57±36.46 μg/mL), α-amylase (315.89±3.83 μg/mL), and pancreatic lipase (230.475±9.65 μg/mL) activity indicate that the activity of fruit ethanolic extract is better than all other extracts of the plant. The gas chromatography–mass spectroscopy analysis of the fruit ethanolic extract showed the presence of a number of bioactive compounds such as butyl butyrate, 5-hydroxymethyl furfural, 1-butoxy-1-isobutoxy butane, malic acid, tetradecanoic acid, phytol acetate, trans phytol, n-hexadecanoic acid, 9Z,12Z-octadecadienoic acid, stearic acid, sitosterol, 3,5-dihydroxy-6-methyl-2,3-dihydro-4H-pyran-4-one, and 2,4,5-trimethyl-2,4-dihydro-3H-pyrazol-3-one. The results of this study suggest that the ethanolic extract of the fruit of F. carica may have potential antidiabetic and antiobesogenic agents.

Immobilization of a Cutinase from Fusarium oxysporum and Application in Pineapple Flavor Synthesis.

In the present study, the immobilization of a cutinase from Fusarium oxysporum was carried out as cross-linked enzyme aggregates. Under optimal immobilization conditions, acetonitrile was selected as precipitant, utilizing 9.4 mg protein/mL and 10 mM glutaraldehyde as cross-linker. The immobilized cutinase (imFocut5a) was tested in isooctane for the synthesis of short-chain butyrate esters, displaying enhanced thermostability compared to the free enzyme. Pineapple flavor (butyl butyrate) synthesis was optimized, leading to a conversion yield of >99% after 6 h, with an initial reaction rate of 18.2 mmol/L/h. Optimal reaction conditions were found to be 50 °C, a vinyl butyrate/butanol molar ratio of 3:1, vinyl butyrate concentration of 100 mM, and enzyme loading of 11 U. Reusability studies of imFocut5a showed that after four consecutive runs, the reaction yield reaches 54% of the maximum. The efficient bioconversion offers a sustainable and environmentally friendly process for the production of "natural" aroma compounds essential for the food industry.

In situ esterification and extractive fermentation for butyl butyrate production with Clostridium tyrobutyricum.

Butyl butyrate (BB) is a valuable chemical that can be used as flavor, fragrance, extractant, and so on in various industries. Meanwhile, BB can also be used as a fuel source with excellent compatibility as gasoline, aviation kerosene, and diesel components. The conventional industrial production of BB is highly energy-consuming and generates various environmental pollutants. Recently, there have been tremendous interests in producing BB from renewable resources through biological routes. In this study, based on the fermentation using the hyper-butyrate producing strain Clostridium tyrobutyricum ATCC 25755, efficient BB production through in situ esterification was achieved by supplementation of lipase and butanol into the fermentation. Three commercially available lipases were assessed and the one from Candida sp. (recombinant, expressed in Aspergillus niger) was identified with highest catalytic activity for BB production. Various conditions that might affect BB production in the fermentation have been further evaluated, including the extractant type, enzyme loading, agitation, pH, and butanol supplementation strategy. Under the optimized conditions (5.0 g L-1 of enzyme loading, pH at 5.5, butanol kept at 10.0 g L-1 ), 34.7 g L-1 BB was obtained with complete consumption of 50 g L-1 glucose as the starting substrate. To our best knowledge, the BB production achieved in this study is the highest among the ever reported from the batch fermentation process. Our results demonstrated an excellent biological platform for renewable BB production from low-value carbon sources. Biotechnol. Bioeng. 2017;114: 1428-1437. © 2017 Wiley Periodicals, Inc.

Experimental study of the gaseous and particulate matter emissions from a gas turbine combustor burning butyl butyrate and ethanol blends

This paper reports the gaseous pollutants and Particulate Matter (PM) emissions of a gas turbine combustor burning butyl butyrate and ethanol blends. The gas turbine has been tested under two operational conditions to represent the cruising (condition 1) and idling (condition 2) conditions of aero engines. Aviation kerosene RP-3 and four different biofuels using butyl butyrate (BB) and ethanol blends were tested and compared to evaluate the impact of fuel composition on CO, NOx, unburnt hydrocarbon (UHC) and PM emissions under selected two operational conditions. The PM number (PN) concentration and size distributions were measured by a scanning mobility particle sizer (SMPS). The compositions of filter borne PM were analysed by ion chromatograph technique. The concentrations of CO, NOx and UHC were detected and analysed by a gas analyser. Results indicated that under idling and cruising conditions the CO emissions from butyl butyrate and ethanol blends were higher than that of RP-3 due to the relatively lower combustion temperature of the biofuels compared with that of RP-3. Results of the NOx emission comparison indicated the biofuels produced less NOx than RP-3 and the increase of ethanol content in the biofuels could reduce the NOx and UHC emissions. The particles smaller than 20nm played a dominant role in PN emissions at condition 1 with the range from 2×106/cm3 to 4×107/cm3. There was a peak value of particle number concentration with the particle size ranging from about 25nm and 40nm. The PN emission index at condition 1 was higher than that at condition 2 for the biofuels, whilst the trend was opposite to that of RP-3. The ions analysis indicated Ca2+ and SO42− were the two dominant ions in the PM emissions of biofuels.

Production of Whole-Cell Lipase from Streptomyces clavuligerus in a Bench-Scale Bioreactor and Its First Evaluation as Biocatalyst for Synthesis in Organic Medium.

This work evaluated a wild-type Streptomyces clavuligerus strain as a whole-cell lipase (Sc-WCL) producer by submerged fermentation. In an orbital shaker, lipase hydrolytic activity of 3000UL-1, measured at pH9.0 and 37°C by using p-nitrophenyl palmitate as substrate, was achieved after 36h fermentation using glycerol-free production medium in a baffled Erlenmeyer flask at 28°C and pH6.8. Maximum productivity of 52.5UL-1h-1 was achieved after 24h in bioreactor using glycerol-free production medium at pH6.8 and 28°C, with agitation at 400rpm and aeration at 1vvm. Sc-WCL was shown to be more active at 60°C and pH10.7, while higher activity retention was observed at 30-40°C after 1h incubation at pH10. Sc-WCL showed to have potential to be used as biocatalyst in hydrolysis and esterification reactions. In the hydrolysis of p-nitrophenyl palmitate, lyophilized Sc-WCL expressed a hydrolytic activity (330unitsg-1 solid, measured at 37°C and pH9.0) around 100-fold higher than the ones declared by a supplier of lyophilized powders of mixtures of intracellular lipases from Thermus thermophiles and Thermus flavus (≥3.0unitsg-1 solid, measured at 65°C and pH8.0). In the synthesis of butyl butyrate in anhydrous medium, 85% ester conversion was achieved at 37°C after 8h reaction. Thus, Sc-WCL showed to be a promising biocatalyst because it is cheaper than the isolated and purified lipases.

Techno-economic evaluation of an ultrasound-assisted Enzymatic Reactive Distillation process

Enzymatic Reactive Distillation (ERD) is a bioreactive process, in which enzymes are immobilized on column internal surface, and helps to overcome chemical reaction and phase equilibrium limitations. The activation of enzymes by ultrasound (US) leads to ultrasound-assisted ERD (US-ERD) which might display more eco-efficiency than standard processing of valuable chemicals. Reaction rate improvements of more than 50% could be achieved by the assistance of US.An US-ERD process for the synthesis of butyl butyrate (10kilotons per year, 99 wt% purity) was designed. A techno-economic evaluation via process optimization was carried out to minimize the annual costs, by using an evolutionary algorithm. The techno-economic evaluation shows that the US-ERD process and the ERD share nearly equal costs. Installation costs of the US equipment are high but they are compensated by a 12% lower reactive section height and a 7% lower total height of the US-ERD column in comparison to ERD.

Experimental and Modeling Study of Esterification Reaction for Synthesis of Butyl Butyrate: Desirability Function Approach for Optimization and Prediction Comparative Study of RSM and ANN

AbstractButyl butyrate was synthesized by esterification of butyric acid with n-butanol using homogeneous catalyst methanesulfonic acid (MSA). The esterification process was optimized by the application of response surface methodology (RSM) and artificial neural network (ANN). 3 level-4 variables central composite design (CCD) of RSM and MLP 4-9-1 network of ANN was chosen for the experimental design and analysis. The quadratic response model of RSM was optimized using desirability function approach. Effects of independent variables on the yield of butyl butyrate were investigated. Various training algorithm such as IBP, QP, GA, LM, BFGS, and CG was used for training experimental response data for the ANN study. By sensitivity analysis, the relative significance of 36.98 % confirmed that the molar ratio was the main affecting parameter on the yield of butyl butyrate. In prediction comparative study, ANN model was found better than the RSM model with high values ofR2(0.9998) and lower values of RMSE (0.2435), SEP (0.324 %), and AAD (0.0086 %) compared to RSM (R2=0.9862, RMSE=2.3095, SEP=3.076 %, AAD=0.6459 %). The accuracy of the RSM and ANN models were judged by validation test by performing unseen data experiments.

Dehydrogenative coupling promoted by copper catalysts: a way to optimise and upgrade bio-alcohols

A one-pot one-step transformation of butanol into butyl butanoate takes place with excellent yield on a Cu/ZrO2 catalyst.

Triphasic esterification of butanol and butyric acid in fermentation media

Abstract Butanol and butyric acid produced from acetone-butanol-ethanol (ABE) fermentation can be used to produce butyl butyrate, an important fragrance ester. However, low levels of butanol and butyric acid need to be purified from culture media first with energy-intensive distillation processes. In this study, a triphasic (organic/aqueous/fluorous) system is developed to esterify butanol and butyric acid in spent culture media into butyl butyrate directly without purification. The produced butyl butyrate forms a distinct organic phase floating on top and can then be separated easily. In a model system containing 37.1 g/L of butanol and 44.1 g/L of butyric acid, 57% of the butanol is converted to butyl butyrate after 8 h of esterification. With multiple cycles of esterification and product removal, butanol conversion can be further increased to 86%. When spent culture medium containing 7.12 g/L of butanol and 4.81 g/L of butyric acid is used for esterification, 38% of butanol (0.36 mmol) is consumed and 0.33 mmol of butyl butyrate is produced. However, when ABE fermentation and esterification are carried out simultaneously, only 0.042 mmol of butyl butyrate is produced, probably due to the incompatible pH requirements for cell growth (pH 5–7) and esterification (pH 2–3).