Optimization of enzymatic production of biodiesel from castor oil in organic solvent medium

We studied the production of fatty acid ethyl esters from castor oil using n-hexane as solvent and two commercial lipases, Novozym 435 and Lipozyme IM, as catalysts. For this purpose, a Taguchi experimental design was adopted considering the following variables: temperature (35–65°C), water (0–10 wt/wt%), and enzyme (5–20 wt/wt%) concentrations and oil-to-ethanol molar ratio (1∶3 to 1∶10). An empirical model was then built so as to assess the main and cross-variable effects on the reaction conversion and also to maximize biodiesel production for each enzyme. For the system containing Novozym 435 as tatalyst the maximum conversion obtained was 81.4% at 65°C, enzyme concentration of 20 wt/wt%, water concentration of 0 wt/wt%, and oil-to-ethanol molar ratio of 1∶10. When the catalyst was Lipozyme IM, a conversion as high as 98% was obtained at 65°C, enzyme concentration of 20 wt/wt%, water concentration of 0 wt/wt%, and oil-to-ethanol molar ratio of 1∶3.     

Biodiesel fuel production by the transesterification reaction of soybean oil using immobilized lipase

The enzymatic alcoholysis of soybean oil with methanol and ethanol was investigated using a commercial, immobilized lipase (Lipozyme RMIM). The effect of alcohol (methanol or ethanol), enzyme concentration, molar ratio of alcohol to soybean oil, solvent, and temperature on biodiesel production was determined. The best conditions were obtained in a solvent-free system with ethanol/oil molar ratio of 3.0, temperature of 50 degrees C, and enzyme concentration of 7.0% (w/w). Three-step batch ethanolysis was most effective for the production of biodiesel. Ethyl esters yield was about 60% after 4 h of reaction.     

Kinetics of enzyme-catalyzed alcoholysis of soybean oil in n-hexane

This work investigated the production of fatty acid ethyl esters (FAEEs) from soybean oil using n-hexane as solvent and two commercial lipases as catalysts, Novozym 435 and Lipozyme IM. A Taguchi experimental design was adopted considering the variables temperature (35–65°C), addition of water (0–10 wt/wt%), enzyme (5–20 wt/wt%) concentration, and oil-to-ethanol molar ratio (1:3–1:10). It is shown that complete conversion in FAEE is achieved for some experimental conditions. The effects of process variables on reaction conversion and kinetics of the enzymatic reactions are presented for all experimental conditions investigated in the factorial design.     

酸化油固定床酶法合成生物柴油研究

酸化油是油脂工作中以皂脚、油脚经酸化处理得到的产品.它的主要成份是游离脂肪酸及中性油,是生产脂肪酸的重要原料,但生产过程中有水解废水的产生,若将其直接排放,既污染了环境又浪费了资源.     

Study of immobilized candida rugosa lipase for biodiesel fuel production from palm oil by flow microcalorimetry

Enzymatic transesterification of palm oil with methanol and ethanol was studied. Of the four lipases that were tested in the initial screening, lipase Candida Rugosa (CR) resulted in the highest yield of mono alkyl esters. Lipase CR was further investigated in immobilized form within an activated carbon as support. The activated carbon was prepared by activation physical. Using the immobilized lipase CR, the effects of water and alcohol concentration, enzyme loading and enzyme thermal stability in the transesterification reaction were investigated. The optimal conditions for processing 50 g of palm oil were: 37 °C, 1:14.5 oil/methanol molar ratio, 1.0 g water and 500 mg lipase for the reactions with methanol, 35 °C, 1:15.0 oil/ethanol molar ratio, 1.0 g water, 500 mg lipase for the reactions with ethanol, and 35 °C, 1:10.0 oil/n-butanol molar ratio, 1.0 g water, 500 mg lipase for the reactions with ethanol. Subject to the optimal conditions, methyl and ethyl esters formation of 70 and 85 mol% in 1 h of reaction were obtained for the immobilized enzyme reactions. The flow microcalorimetry is an important and novel techniques is used in evaluation of biodiesel production.     

Synthesis of Rapeseed Biodiesel Using Short-Chained Alkyl Acetates as Acyl Acceptor

In this study, we conducted experiments using a response surface methodology to determine the optimal reaction conditions for the enzymatic synthesis of biodiesel from rapeseed oil and short-chained alkyl acetates, such as methyl acetate or ethyl acetate, as the acyl acceptor at 40 °C. Based on our response surface methodology experiments, the optimal reaction conditions for the synthesis of biodiesel were as follows: methyl acetate as acyl acceptor, catalyst concentration of 16.50%, oil-to-methyl acetate molar ratio of 1:12.44, and reaction time of 19.70 h; ethyl acetate as acyl acceptor, catalyst concentration of 16.95%, oil-to-ethyl acetate molar ratio of 1:12.56, and reaction time of 19.73 h. The fatty acid ester content under the above conditions when methyl acetate and ethyl acetate were used as the acyl acceptor was 58.0% and 62.6%, respectively. The statistical method described in this study can be applied to effectively optimize the enzymatic conditions required for biodiesel production with short-chained alkyl acetates.     

Biodiesel Production from Integration Between Reaction and Separation System: Reactive Distillation Process

Biodiesel is a clean burning fuel derived from a renewable feedstock such as vegetable oil or animal fat. It is biodegradable, non-inflammable, non-toxic, and produces lesser carbon monoxide, sulfur dioxide, and unburned hydrocarbons than petroleum-based fuel. The purpose of the present work is to present an efficient process using reactive distillation columns applied to biodiesel production. Reactive distillation is the simultaneous implementation of reaction and separation within a single unit of column. Nowadays, it is appropriately called “Intensified Process”. This combined operation is especially suited for the chemical reaction limited by equilibrium constraints, since one or more of the products of the reaction are continuously separated from the reactants. This work presents the biodiesel production from soybean oil and bioethanol by reactive distillation. Different variables affect the conventional biodiesel production process such as: catalyst concentration, reaction temperature, level of agitation, ethanol/soybean oil molar ratio, reaction time, and raw material type. In this study, the experimental design was used to optimize the following process variables: the catalyst concentration (from 0.5 wt.% to 1.5 wt.%), the ethanol/soybean oil molar ratio (from 3:1 to 9:1). The reactive column reflux rate was 83 ml/min, and the reaction time was 6 min.     

Enzyme catalyzed production of biodiesel from olive oil

Biodiesel (fatty acid methyl esters) was produced by transesterification of triglycerides (triolein) present in olive oil with methanol and Novozym435. The effect of the molar ratio of methanol to triolein, semibatch (stepwise addition of methanol) vs batch operation, enzyme activity, and reaction temperature on overall conversion was determined. Stepwise methanolysis with a 3:1 methanol to triolein molar ratio and an overall ratio of 8:1 gave the best results. The final conversion and yield of biodiesel were unaffected by initial enzyme concentrations greater than 500 U/mL olive oil. The optimum reaction temperature was 60 degrees C. Comparison of conversion data between a test-tube scale reactor and a 2-L batch reactor revealed that the difference in conversion was within 10%. Experiments were also carried out with used cooking oil; the conversion with used cooking oil was slightly lower but no major differences were observed. The efficacy of Novozym435 was determined by reusing the enzyme; although the enzyme's relative activity decreased with reuse, it still retained 95% of its activity after five batches and more than 70% after as many as eight batches.     

Enzymatic Biodiesel Synthesis in Semi-Pilot Continuous Process in Near-Critical Carbon Dioxide

A semi-pilot continuous process (SPCP) for enzymatic biodiesel synthesis utilizing near-critical carbon dioxide (NcCO₂) as the reaction medium was developed with the aim of reducing the reaction time and alleviating the catalyst inhibition by methanol. Biodiesel synthesis was evaluated in both lab-scale and semi-pilot scale reactors (batch and continuous reactors). In a SPCP, the highest conversion (～99.9 %) in four and a half hours was observed when three-step substrate (methanol) addition (molar ratio [oil/methanol]?=?1:1.3) was used and the reaction mixture containing enzyme (Lipozyme TL IM, 20 wt.% of oil) was continuously mixed (agitation speed?=?300 rpm) at 30 °C and 100 bar in a CO₂ environment. The biodiesel produced from canola oil conformed to the fuel standard (EU) even without additional downstream processing, other than glycerol separation and drying.     

Comparison and optimisation of biodiesel production from <Emphasis Type="Italic">Jatropha curcas</Emphasis> oil using supercritical methyl acetate and methanol

In this study, biodiesel has been successfully produced by transesterification using non-catalytic supercritical methanol and methyl acetate. The variables studied, such as reaction time, reaction temperature and molar ratio of methanol or methyl acetate to oil, were optimised to obtain the optimum yield of fatty acid methyl ester (FAME). Subsequently, the results for both reactions were analysed and compared via Response Surface Methodology (RSM) analysis. The mathematical models for both reactions were found to be adequate to predict the optimum yield of biodiesel. The results from the optimisation studies showed that a yield of 89.4 % was achieved for the reaction with supercritical methanol within the reaction time of 27 min, reaction temperature of 358°C, and methanol-to-oil molar ratio of 44. For the reaction in the presence of supercritical methyl acetate, the optimum conditions were found to be: reaction time of 32 min, reaction temperature of 400°C, and methyl acetate-to-oil molar ratio of 50 to achieve 71.9 % biodiesel yield. The differences in the behaviour of methanol and methyl acetate in the transesterification reaction are largely due to the difference in reactivity and mutual solubility of Jatropha curcas oil and methanol/methyl acetate.     

Optimization of Biodiesel Production from Castor Oil Using Response Surface Methodology

The short supply of edible vegetable oils is the limiting factor in the progression of biodiesel technology; thus, in this study, we applied response surface methodology in order to optimize the reaction factors for biodiesel synthesis from inedible castor oil. Specifically, we evaluated the effects of multiple parameters and their reciprocal interactions using a five-level three-factor design. In a total of 20 individual experiments, we optimized the reaction temperature, oil-to-methanol molar ratio, and quantity of catalyst. Our model equation predicted that the following conditions would generate the maximum quantity of castor biodiesel (92 wt.%): a 40-min reaction at 35.5 °C, with an oil-to-methanol molar ratio of 1:8.24, and a catalyst concentration of 1.45% of KOH by weight of castor oil. Subsequent empirical analyses of the biodiesel generated under the predicted conditions showed that the model equation accurately predicted castor biodiesel yields within the tested ranges. The biodiesel produced from castor oil satisfied the relevant quality standards without regard to viscosity and cold filter plugging point.     

Enzymatic Synthesis of Biodiesel via Alcoholysis of Palm Oil

The enzymatic alcoholysis of crude palm oil with methanol and ethanol was investigated using commercial immobilized lipases (Lipozyme RM IM, Lipozyme TL IM). The effect of alcohol (methanol or ethanol), molar ratio of alcohol to crude palm oil, and temperature on biodiesel production was determined. The best ethyl ester yield was about 25 wt.% and was obtained with ethanol/oil molar ratio of 3.0, temperature of 50 °C, enzyme concentration of 3.0 wt.%, and stepwise addition of the alcohol after 4 h of reaction. Experiments with 1 and 3 wt.% of KOH and 3 wt.% of MgO were carried out to compare their catalytic behavior with the enzymatic transesterification results. The commercial immobilized lipase, Lipozyme TL IM, showed the best catalytic performance.     

Optimization of biodiesel production from castor oil

The transesterification of castor oil with ethanol in the presence of sodium ethoxide as catalyst is an exceptional option for the Brazilian biodiesel production, because the castor nut is quite available in the country. Chemically, its oil contains about 90% of ricinoleic acid that gives to the oil some beneficial characteristics such as its alcohol solubility at 30°C. The transesterification variables studied in this work were reaction temperature, catalyst concentration and alcohol oil molar ratio. Through a star configuration experimental design with central points, this study shows that it is possible to achieve the same conversion of esters carrying out the transesterification reaction with a smaller alcohol quantity, and a new methodology was developed to obtain high purity biodiesel.     

固定化脂肪酶催化碳酸二甲酯制备生物柴油的研究

以介孔硅材料(MPS)为载体将脂肪酶固定化,以碳酸二甲酯为酰基受体,对固定化酶催化碳酸二甲酯进行了反应路径(原料油)、反应条件(反应温度、碳酸二甲酯的用量、加水量)的优化,在最佳的条件下对实验过程中所用的固定化酶进行重复使用性的考察.实验结果表明,不同种油与碳酸二甲酯反应在同定化酶的催化下制备生物柴油的产率以麻疯树油为最高,最佳反应条件是碳酸二甲酯的浓度为16mL/g、不加水,在50℃下反应24h,生物柴油得率达81.6％.     

Kinetic study on enantioselective resolution of (R,S)-2-phenylpropionic acid through Novozyme 435–catalyzed esterification

2-Phenylpropionic acid (2-PPA) is a very important chiral intermediate in the synthesis of aryl propionic acid drugs with anti-inflammatory and analgesic effects. Enzymatic kinetic resolution of (R,S)-2-PPA using n-hexanol as an acyl donor was carried out in n-hexane. Lipases from different sources were used to catalyze the esterification of 2-PPA, among which Novozyme 435 had the highest catalytic efficiency. The effects of reaction conditions on conversion (c) and enantiomeric excess (ee), involving temperature, substrate concentrations, enzyme loading, and reaction time were investigated. The kinetic model based on the Ping-Pong bi-bi mechanism was established to simulate the enzymatic esterification process. The experimental values of initial rates of various 2-PPA concentrations were consistent with the simulated values.     

Biodiesel Production from Various Oils Under Supercritical Fluid Conditions by Candida antartica Lipase B Using a Stepwise Reaction Method

In this study, we evaluate the effects of various reaction factors, including pressure, temperature, agitation speed, enzyme concentration, and water content to increase biodiesel production. In addition, biodiesel was produced from various oils to establish the optimal enzymatic process of biodiesel production. Optimal conditions were determined to be as follows: pressure 130 bar, temperature 45 °C, agitation speed 200 rpm, enzyme concentration 20%, and water contents 10%. Among the various oils used for production, olive oil showed the highest yield (65.18%) upon transesterification. However, when biodiesel was produced using a batch system, biodiesel conversion yield was not increased over 65%; therefore, a stepwise reaction was conducted to increase biodiesel production. When a reaction medium with an initial concentration of methanol of 60 mmol was used and adjusted to maintain this concentration of methanol every 1.5 h during biodiesel production, the conversion yield of biodiesel was 98.92% at 6 h. Finally, reusability was evaluated using immobilized lipase to determine if this method was applicable for industrial biodiesel production. When biodiesel was produced repeatedly, the conversion rate was maintained at over 85% after eight reuses.     

Biodiesel production and comparison using commercial lipase and chemical catalyst from Cassia auriculata oil

In this present investigation, Cassia auriculata was explored as a feedstock for production of biodiesel. Transesterification reaction was performed by both enzyme (lipase) and chemical (potassium hydroxide) catalyst with diverse acyl acceptors such as methanol, ethanol, propanol, n-propanol, butanol, n- butanol, and finally their biodiesel yield were also recorded. Process optimization was performed by both one factor at a time method and response surface method. The maximal biodiesel yield of 92% (weight/weight) was obtained at the following optimal conditions: Oil:Methanol molar ratio of 1:6 (moles/moles), the lipase concentration of 2% (weight/weight), at 35 ?°C and 120 ?min. The highest biodiesel yield from Cassia auriculata oil was occurred with excess methanol that aids the equilibrium shift in the forward direction. The kinetics of the transesterification reaction was investigated under optimal conditions and the activation energy was found to be 14.91 ?kJ/mol. Simultaneously Gas Chromatography – Mass Spectroscopy was also carried out for the biodiesel produced from Cassia auriculata and the same has been reported. The GC analysis declares the existence of fatty acid esters like hexadecanoic acid methyl ester, methyl stearate and the peak with retention time 12.8 ?min signifies the evidence of hexadecanoic acid methyl ester with 28% of yield content. This investigation also evaluated the biodiesel quality produced from lipase-transesterified Cassia auriculata oil based on fuel properties. Biodiesel properties Flash Point (FC), Pour Point (PP) and kinematic viscosity were compared with American (ASTM 6751) and European (EN 14214) Standards. Cassia auriculata oil had PP 6.7 ?°C and Kinematic viscosity (813 ?kg/m³) that agreed with both the standards. Thus this study showed that Cassia auriculata oil could be a better fuel alternative with further improvement of fuel properties.     

Thermal characterization of oil and biodiesel from oiticica (<Emphasis Type="Italic">Licania rigida</Emphasis> Benth)

Searching for other alternative sources, which are not part of the food chain, and which are able to supply the biofuel market is a promising option. In this context, it has been searched to investigate the oiticica oil, approaching its availability to the biodiesel synthesis, as well as its thermal stability. Few works retreat parameters such as: the optimization of the biodiesel synthesis, its physical–chemical properties, and thermal parameters etc. The characterization results revealed that the oil showed very high kinematic viscosity, and acidity value around 13 mg KOH/g, requiring a pre-treatment. To reduce the acid in the oil, it has been done the esterification of oil, which was studied in different molar ratios oiticica oil/ethanol (1:9) and 2.0% catalyst, in order to get the best reduction the index of acidity. The lowest level of acidity of the oil obtained after the esterification was 4.4 mg KOH/g. The reaction rate for the synthesis of biodiesel, compared to the initial mass of oiticica oil ester was 85%. This income can be overcome by pursuing an even smaller reduction of acid value of biodiesel oiticica. The acid value of biodiesel was 1.8 mg KOH/g. The results have revealed that the oiticica oil and biodiesel are stable at 224 and 179 °C, respectively.     

基于氯化镁饱和溶液中固定化脂肪酶Lipozyme TL IM催化光皮树油脂合成生物柴油

基于氯化镁饱和溶液反应体系中,对采用固定化脂肪酶Lipozyme TL IM催化光皮树油脂转化为生物柴油的工艺进行了研究。考察了固定化脂肪酶Lipozyme TL IM催化光皮树油转酯化的工艺中甲醇的用量、固定化脂肪酶的添加量、摇床的转速和反应时间对生物柴油产率的影响。实验结果表明,采用氯化镁饱和溶液反应体系,在醇油摩尔比为3∶1,固定化酶Lipozyme TL IM用量为光皮树油质量的20%,摇床转速为150 r/min,反应8 h时,生物柴油产率最高,达到86.5%。与传统的三步甲醇醇解或者有机溶剂反应体系比较,采用的氯化镁饱和溶液体系的酶稳定性更好,反应效率更高,有效地解决了酶在甲醇中失活的问题,生产成本低,可成为生产生物柴油的新工艺。     

废茶油的精制及其合成生物柴油的研究

本文以废茶油为原料,经过脱胶脱酸等预处理后与甲醇进行酯交换反应制取生物柴油.探讨了反应时间、反应温度、醇-油摩尔比和催化剂用量等因素对废茶油-甲醇酯交换反应的影响,并且采用正交实验优化合成条件,确定了反应的最佳操作条件以及影响反应的关键因素.研究结果表明,酯交换反应进行的最佳反应条件为:醇油摩尔比为25:1、催化剂用量为油重的1.0%、反应时间为30min、反应温度为60℃,茶油酸甲酯产率77.34%.