Enzymatic Biodiesel Production from Sunflower Oil by Candida antarctica Lipase in a Solvent-free System

A Review on Opportunities and Limitations of Membrane Bioreactor Configuration in Biofuel Production

Biofuels are a clean and renewable source of energy that has gained more attention in recent years; however, high energy input and processing cost during the production and recovery process restricted its progress. Membrane technology offers a range of energy-saving separation for product recovery and purification in biorefining along with biofuel production processes. Membrane separation techniques in combination with different biological processes increase cell concentration in the bioreactor, reduce product inhibition, decrease chemical consumption, reduce energy requirements, and further increase product concentration and productivity. Certain membrane bioreactors have evolved with the ability to deal with different biological production and separation processes to make them cost-effective, but there are certain limitations. The present review describes the advantages and limitations of membrane bioreactors to produce different biofuels with the ability to simplify upstream and downstream processes in terms of sustainability and economics.

Combined immobilized lipases for effective biodiesel production from spent coffee grounds

This work describes the enzymatic transesterification of the oil extracted from SCGs for synthesis of biodiesel as a promising alternative to diesel fuels based on petroleum. Biocatalysts from various sources were tested for biodiesel synthesis using coffee oil among which CaCO3- immobilized Staphylococcus aureus and Bacillus stearothermophilus showed the highest conversion yields (61 ± 2.64% and 64.3 ± 1.53%, respectively) in 4 h. In further optimizing reaction parameters, methanol to oil molar ratio, biocatalyst quantity, water content, as well as incubation time and temperature markedly improved oil-to-biodiesel conversion up to 99.33 ± 0.57 % in a solvent free reaction after 12 h at 55 °C. A mixture of inexpensive CaCO3-immobilized bacterial lipases at a 1:1 ratio was the best environment-friendly catalyst for biofuel synthesis as well as the ideal trade-off between conversion and cost. Obtained coffee biodiesel remained stable beyond 40 days at ambient storage conditions and its chemical characteristics were comparable to those of other known biodiesels according to the European requirements (EN14214). Collectively, SCGs, after oil extraction, could be an ideal substrate for the production of an environment-friendly biodiesel by using appropriate mixture of CaCO3-immobilized lipases.

Biological Methods in Biodiesel Production and Their Environmental Impact

This publication presents the technologies of enzymatic biodiesel production in comparison to the conventional methods using acid and base catalysts. Transesterification with conventional catalysts has some disadvantages, and for this reason, alternative methods of biodiesel production have been investigated. These solutions include the replacement of chemical catalysts with biological ones, which show substrate specificity in relation to fats. Replacing chemical with biological catalysts causes elimination of some disadvantages of chemical processes, for instance: high temperatures of reaction, problematic process of glycerol purification, higher alcohol-to-oil molar ratios, and soap formation. Moreover, it causes operational cost reduction and has a positive environmental impact. This is due to the lower temperature of the process, which in turn translates into lower cost of equipment and lower GHG emissions associated with the need to provide less heat to the process. The increase of biofuels’ demand has led to the technology of enzymatic biodiesel production being constantly being developed. This research mainly focuses on the possibility of obtaining cheaper and more effective biocatalysts, as well as increasing the durability of enzyme immobilization on different materials.

Enzyme catalysis coupled with artificial membranes towards process intensification in biorefinery- a review

In this review, for the first time, the conjugation of the major types of enzymes used in biorefineries and the membrane processes to develop different configurations of MBRs, was analyzedfor the production of biofuels, phytotherapics and food ingredients. In particular, the aim is to critically review all the works related to the application of MBR in biorefinery, highlighting the advantages and the main drawbacks which can interfere with the development of this system at industrial scale. Alternatives strategies to overcome main limits will be also described in the different application fields, such as the use of biofunctionalized magnetic nanoparticles associated with membrane processes for enzyme re-use and membrane cleaning or the membrane fouling control by the use of integrated membrane process associated with MBR.

Progress in Enzymatic Biodiesel Production and Commercialization

Enzymatic biodiesel production has attracted tremendous interest due to its well-recognized advantages. However, high enzyme costs limit the application of enzymatic processes in industrial production. In the past decade, great improvements have been achieved in the lab and the industrial scale, and the production cost of the enzymatic process has been reduced significantly, which has led to it being economically competitive compared to the chemical process. This paper summarizes the progress achieved in enzymatic biodiesel research and commercialization, including reducing enzyme cost, expanding low-quality raw materials, and novel reactor designs. The advantages and disadvantages of different enzymatic processes are also compared.

Widely used catalysts in biodiesel production: a review

An ever-increasing energy demand and environmental problems associated with exhaustible fossil fuels have led to the search for an alternative renewable source of energy. In this context, biodiesel has attracted attention worldwide as an eco-friendly alternative to fossil fuel for being renewable, non-toxic, biodegradable, and carbon-neutral. Although the homogeneous catalyst has its own merits, much attention is currently paid toward the chemical synthesis of heterogeneous catalysts for biodiesel production as it can be tuned as per specific requirement and easily recovered, thus enhancing reusability. Recently, biomass-derived heterogeneous catalysts have risen to the forefront of biodiesel productions because of their sustainable, economical and eco-friendly nature. Furthermore, nano and bifunctional catalysts have emerged as a powerful catalyst largely due to their high surface area, and potential to convert free fatty acids and triglycerides to biodiesel, respectively. This review highlights the latest synthesis routes of various types of catalysts (including acidic, basic, bifunctional and nanocatalysts) derived from different chemicals, as well as biomass. In addition, the impacts of different methods of preparation of catalysts on the yield of biodiesel are also discussed in details.

An ever-increasing energy demand and environmental problems associated with exhaustible fossil fuels have led to the search for an alternative energy. In this context, biodiesel has attracted attention worldwide as an alternative to fossil fuel.

Techno-Economic Performance of Different Technological Based Bio-Refineries for Biofuel Production

There are different technologies for biodiesel production, each having its benefits and drawbacks depending on the type of feedstock and catalyst used. In this study, the techno-economic performances of four catalyst technologies were investigated. The catalysts were bulk calcium oxide (CaO), enzyme, nano-calcium oxide, and ionic liquid. The study was mainly based on process simulations designed using Aspen Plus and SuperPro software. The quantity and quality of biodiesel and glycerol, as well as the amount of biodiesel per amount of feedstock, were the parameters to evaluate technical performances. The parameters for economic performances were total investment cost, unit production cost, net present value (NPV), internal return rate (IRR), and return over investment (ROI). Technically, all the studied options provided fuel quality biodiesel and high purity glycerol. However, under the assumed market scenario, the process using bulk CaO catalyst was more economically feasible and tolerable to the change in market values of major inputs and outputs. On the contrary, the enzyme catalyst option was very expensive and economically infeasible for all considered ranges of cost of feedstock and product. The result of this study could be used as a basis to do detail estimates for the practical implementation of the efficient process.

Bioprospecting hot spring metagenome: lipase for the production of biodiesel

Screening of metagenomic library from Taptapani Hot Spring (Odisha) yielded a positive lipase clone (pUC-lip479). Sequence analysis showed an ORF (RK-lip479) of 416 amino acid residues which was overexpressed in Escherichia coli BL21 (DE3). Optimum pH and temperature of purified lipase RK-lip479 were 8.0 and 65 °C, respectively, and found to be stable over a pH range of 7.0-9.0 and temperatures 55-75 °C. RK-lip479 could hydrolyse a wide range of 4-nitrophenyl esters (4-nitrophenyoctanoate, 4-nitrophenyldodecanoate, 4-nitrophenylpalmitate, 4-nitrophenylmyristate and 4-nitrophenylstearate), and maximum activity was observed with 4-nitrophenyldodecanoate. RK-lip479 was resistant to many organic solvents, especially isopropanol, DMSO, methanol, DMF, ethanol, dichloromethane, acetone, glycerol and ethyl acetate. RK-lip479 also showed activity in the presence of monovalent (Na⁺ and K⁺), divalent (Mg²⁺, Mn²⁺, Ca²⁺, Hg²⁺, Cu²⁺, Co²⁺, Zn²⁺ and Ag²⁺ ) and trivalent cations (Fe³⁺ and Al³⁺). Yield of biodiesel production was in the range of 40-76% using various waste oils with RK-Lip479 under optimized conditions.

Dual bioimprinting of Thermomyces lanuginosus lipase for synthesis of biodiesel

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High activity TLL is made by dually bioimprinting with substrate alcohol and a surfactant.

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TLL (28 U/g of oil) bioimprinted with only the surfactants could yield 99% biodiesel from soybean oil in about 4 h.

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Dually bioimprinted TLL (only 1.4 U/g of oil) was able to yield 99% biodiesel within 48 h

Use of biodiesel as an alternative to non-renewable sources of energy has become an attractive option in recent years. The enzymatic synthesis of biodiesel by transesterification of fats/oils with an alcohol is a much more sustainable route than the chemical method. However, cost effectiveness of the enzymatic route is a major barrier in its commercialization. In this work, a high activity biocatalyst design of Thermomyces lanuginosus lipase is made by dually bioimprinting it with substrate and a surfactant (which is believed to open up the lid covering the active site of the lipase) during precipitation of the lipase in organic solvent. When the lipase was bioimprinted with only the surfactants, 28 U of the enzyme/g of oil could yield 99% biodiesel from soybean oil in about 4 h. However, when dually bioimprinted even very low enzyme load 1.4 U/g of oil, yielded 99% biodiesel within 48 h.

Enzyme-catalyzed synthesis and kinetics of ultrasonic-assisted biodiesel production from waste tallow

The use of ultrasonic processing was evaluated for its ability to achieve adequate mixing while providing sufficient activation energy for the enzymatic transesterification of waste tallow. The effects of ultrasonic parameters (amplitude, cycle and pulse) and major reaction factors (molar ratio and enzyme concentration) on the reaction kinetics of biodiesel generation from waste tallow bio-catalyzed by immobilized lipase [Candida antarctica lipase B (CALB)] were investigated. Three sets of experiments namely A, B, and C were conducted. In experiment set A, two factors (ultrasonic amplitude and cycle) were investigated at three levels; in experiment set B, two factors (molar ratio and enzyme concentration) were examined at three levels; and in experiment set C, two factors (ultrasonic amplitude and reaction time) were investigated at five levels. A Ping Pong Bi Bi kinetic model approach was employed to study the effect of ultrasonic amplitude on the enzymatic transesterification. Kinetic constants of transesterification reaction were determined at different ultrasonic amplitudes (30%, 35%, 40%, 45%, and 50%) and enzyme concentrations (4, 6, and 8 wt.% of fat) at constant molar ratio (fat:methanol); 1:6, and ultrasonic cycle; 5 Hz. Optimal conditions for ultrasound-assisted biodiesel production from waste tallow were fat:methanol molar ratio, 1:4; catalyst level 6% (w/w of fat); reaction time, 20 min (30 times less than conventional batch processes); ultrasonic amplitude 40% at 5 Hz. The kinetic model results revealed interesting features of ultrasound assisted enzyme-catalyzed transesterification (as compared to conventional system): at ultrasonic amplitude 40%, the reaction activities within the system seemed to be steady after 20 min which means the reaction could proceed with or without ultrasonic mixing. Reversed phase high performance liquid chromatography indicated the biodiesel yield to be 85.6±0.08%.

Heterogeneous catalysis for sustainable biodiesel productionviaesterification and transesterification

Low temperature catalytic conversion of triglycerides and fatty acids sourced from renewable feedstocks represents a key enabling technology for the sustainable production of biodiesel through energy efficient, intensified processes.

Combi-protein coated microcrystals of lipases for production of biodiesel from oil from spent coffee grounds

Background

Replacing chemical catalysts with biocatalysts is a widely recognized goal of white biotechnology. For biocatalytic processes requiring low water containing media, enzymes for example commercial preparations of lipases, show low catalytic efficiencies. Some high activity preparations for addressing this concern have been described. Protein coated microcrystals (PCMC) constitute one such preparation. The present work describes a Combi-PCMC for synthesis of biodiesel from the oil extracted from spent coffee grounds.

Results

Different lipases were screened for biodiesel synthesis from crude coffee oil out of which Novozym 435 gave the best conversion of 60% in 4 h. Optimization of reaction conditions i.e. % water, temperature and purification of coffee oil further enhanced conversion upto 88% in 24 h. A mixture of Novozym 435 and a cheap commercially available 1,3-specific lipase RMIM (from Mucor miehei) was used in different ratios and 1:1 was found to be the best trade-off between conversion and cost. The commercial preparations then were replaced by a novel biocatalyst design called Combi-Protein coated microcrystals (Combi-PCMC) wherein CAL B and Palatase were co-immobilized with K2SO4 as the core and this performed equivalent to the commercial preparations giving 83% conversion in 48 h.

Conclusion

Coffee oil extracted from spent coffee grounds could be used for the synthesis of biodiesel by using appropriate commercial preparations of lipases. The expensive commercially immobilized preparations can also be replaced by a simpler and inexpensive immobilization design called combi-PCMC which synergizes the catalytic action of a nonspecific lipase CAL B and a free form of 1,3-specific lipase from Mucor miehei.

Lipase-catalysed ester synthesis in solvent-free oil system: is it esterification or transesterification?

Ester synthesis was carried out in a solvent-free system of lipase, coconut oil and ethanol or fusel alcohols to ascertain the reaction mechanism. During ester formation, octanoic and decanoic acids increased initially and then decreased gradually, indicating that ester production was a two-step reaction consisting of hydrolysis and esterification, rather than alcoholysis. With ethanol as the alcohol substrate, added butyric acid inhibited ester synthesis. However, when fusel alcohols were used as the alcohol substrate, no significant inhibitory effect by butyric acid was observed. Added octanoic acid did not show any adverse effect on the synthesis of corresponding esters. The results suggest that polarity of the reactants determines lipase activity. This study provides the first evidence on the mechanism of immobilised lipase-catalysed ester synthesis in a solvent-free system involving both hydrolysis and esterification.

Biodiesel production using waste frying oil

Waste sunflower frying oil is used in biodiesel production by transesterification using an enzyme as a catalyst in a batch reactor. Various microbial lipases have been used in transesterification reaction to select an optimum lipase. The effects of various parameters such as temperature, methanol:oil ratio, enzyme concentration and solvent on the conversion of methyl ester have been studied. The Pseudomonas fluorescens enzyme yielded the highest conversion. Using the P. fluorescens enzyme, the optimum conditions included a temperature of 45 °C, an enzyme concentration of 5% and a methanol:oil molar ratio 3:1. To avoid an inhibitory effect, the addition of methanol was performed in three stages. The conversion obtained after 24h of reaction increased from 55.8% to 63.84% because of the stage-wise addition of methanol. The addition of a non-polar solvent result in a higher conversion compared to polar solvents. Transesterification of waste sunflower frying oil under the optimum conditions and single-stage methanol addition was compared to the refined sunflower oil.

Production of biodiesel using immobilized lipase--a critical review

Increase in volume of biodiesel production in the world scenario proves that biodiesel is accepted as an alternative to conventional fuel. Production of biodiesel using alkaline catalyst has been commercially implemented due to its high conversion and low production time. For the product and process development of biodiesel, enzymatic transesterification has been suggested to produce a high purity product with an economic, environment friendly process at mild reaction conditions. The enzyme cost being the main hurdle can be overcome by immobilization. Immobilized enzyme, which has been successfully used in various fields over the soluble counterpart, could be employed in biodiesel production with the aim of reducing the production cost by reusing the enzyme. This review attempts to provide an updated compilation of the studies reported on biodiesel production by using lipase immobilized through various techniques and the parameters, which affect their functionality.

Enzymatic transesterification of Jatropha oil

BACKGROUND

Transesterification of Jatropha oil was carried out in t-butanol solvent using immobilized lipase from Enterobacter aerogenes. The presence of t-butanol significantly reduced the negative effects caused by both methanol and glycerol. The effects of various reaction parameters on transesterification of Jatropha oil were studied.

RESULTS

The maximum yield of biodiesel was 94% (of which 68% conversion was achieved with respect to methyl oleate) with an oil:methanol molar ratio of 1:4, 50 U of immobilized lipase/g of oil, and a t-butanol:oil volume ratio of 0.8:1 at 55 degrees C after 48 h of reaction time. There was negligible loss in lipase activity even after repeated use for seven cycles.

CONCLUSION

To the best of our knowledge this is the first report on biodiesel synthesis using immobilized E. aerogenes lipase.