Lab and pilot plant FAME production through enzyme-catalyzed reaction of low-cost feedstocks

Ethanolysis of degummed soybean oil using magnetic CLEAs from Eversa® Transform

Eversa@ Transform magnetic crosslinked enzyme aggregates (Eversa-mCLEA) have been used to produce fatty acid ethyl esters (FAEEs) through the ethanolysis of soybean oil. Some variables influencing this reaction were studied using an experimental statistical design. After 12 hours of reaction, a maximum FAEEs yield of 64 wt% was obtained using 4 Uest/g oil of Eversa-mCLEA, an anhydrous ethanol/refined oil molar ratio of 11, and a temperature of 40°C. Degummed oil and hydrated ethanol were used as more cost-effective alternatives, leading to an increase in FAEEs yield (up to 73 wt%). The initial reaction rate increased with a lower molar ratio of hydrated ethanol/degummed oil; however, the final yield remained similar. The combined use of Eversa-mCLEA and Lipozyme 435 resulted in 86 wt% FAEEs and 4 wt% of free fatty acids (FFAs) after 24 hours. A caustic polishing step of the product yielded 90 wt% FAEEs and 0.17 wt% FFAs. These findings show that, using these substrates, a more effective purification step (such as fractional distillation) is required for the product to meet international standards for biodiesel commercialization.

Optimization of Enzymatic Transesterification of Acid Oil for Biodiesel Production Using a Low-Cost Lipase: The Effect of Transesterification Conditions and the Synergy of Lipases with Different Regioselectivity

This study describes the enzymatic production of second-generation biodiesel using low-quality acid oil as a substrate. Biolipasa-R, a commercially available and low-cost lipase, was employed for enzymatic transesterification. Response surface methodology was applied to optimize the enzymatic transesterification process. The optimal conditions for biodiesel production, which comprised 42% lipase concentration (per weight of oil), 32% water content (per weight of oil), a methanol to oil molar ratio of 3:1, pH 7.0 and reaction temperature 30°C, resulted in the highest fatty acid methyl ester (FAME) content (71.3%). Subsequently, the synergistic effect of two lipases with different regioselectivities under the optimum transesterification conditions was studied, aiming at the enhancement of process efficiency. The transesterification efficiency of immobilized Biolipasa-R was determined and compared to that of Biolipasa-R in its free form. The results revealed a good performance on FAME content (66.5%), while the recycling of immobilized lipase resulted in a decrease in transesterification efficiency after three consecutive uses.

Trends in the Use of Lipases: A Systematic Review and Bibliometric Analysis

Scientific mapping using bibliometric data network analysis was applied to analyze research works related to lipases and their industrial applications, evaluating the current state of research, challenges, and opportunities in the use of these biocatalysts, based on the evaluation of a large number of publications on the topic, allowing a comprehensive systematic data analysis, which had not yet been conducted in relation to studies specifically covering lipases and their industrial applications. Thus, studies involving lipase enzymes published from 2018 to 2022 were accessed from the Web of Science database. The extracted records result in the analysis of terms of bibliographic compatibility among the articles, co-occurrence of keywords, and co-citation of journals using the VOSviewer algorithm in the construction of bibliometric maps. This systematic review analysis of 357 documents, including original and review articles, revealed studies inspired by lipase enzymes in the research period, showing that the development of research, together with different areas of knowledge, presents good results related to the applications of lipases, due to information synchronization. Furthermore, this review showed the main challenges in lipase applications regarding increased production and operational stability; establishing well-defined evaluation criteria, such as cultivation conditions, activity, biocatalyst stability, type of support and reactor; thermodynamic studies; reuse cycles; and it can assist in defining goals for the development of successful large-scale applications, showing several points for improvement of future studies on lipase enzymes.

Performance of Eversa Transform 2.0 Lipase in Ester Production Using Babassu Oil (Orbignya sp.) and Tucuman Oil (Astrocaryum vulgar): A Comparative Study between Liquid and Immobilized Forms in Fe3O4 Nanoparticles

In this study, biodiesel was produced through the enzymatic esterification of vegetable oils from two common Brazilian palm trees: babassu and tucuman. The oils were hydrolyzed by a chemical route and their free fatty acids esterified with ethanol and methanol using the lipase enzyme Eversa® Transform 2.0 in free forms and supported in iron magnetic nanoparticles (Fe3O4) (enzymatic load: 80 UpNPBg−1). These enzymatic reactions were performed at an oil–alcohol molar ratio of 1:1, reaction temperature of 37 °C, agitation at 150 rpm, and reaction times of 2, 4, 6 and 8 h for the reactions catalyzed by the soluble enzyme and 8 h for the reactions using the biocatalyst. The conversions of fatty acids in ethyl and methyl esters obtained were monitored by gas chromatography (CG). The results obtained from ester synthesis using enzyme catalysts in free form were better: babassu 52.6% (methanol) and 57.5% (ethanol), and for tucuman 96.7% (methanol) and 93.4% (ethanol). In the case of immobilized enzymes, the results obtained ranged from 68.7% to 82.2% for babassu and from 32.5% to 86.0% for tucuman, with three cycles of reuse and without significant catalyst loss. Molecular coupling studies revealed the structures of lipase and that linoleic acid bonded near the active site of the enzyme with the best free energy of −6.5 Kcal/mol.

Enzymatic Synthesis of Fatty Acid Isoamyl Monoesters from Soybean Oil Deodorizer Distillate: A Renewable and Ecofriendly Base Stock for Lubricant Industries

In this study, soybean oil deodorizer distillate (SODD), a mixture of free fatty acids and acylglycerides, and isoamyl alcohol were evaluated as substrates in the synthesis of fatty acid isoamyl monoesters catalyzed by Eversa (a liquid formulation of Thermomyces lanuginosus lipase). SODD and the products were characterized by the chemical and physical properties of lubricant base stocks. The optimal conditions to produce isoamyl fatty acid esters were determined by response surface methodology (RSM) using rotational central composite design (RCCD, 23 factorial + 6 axial points + 5 replications at the central point); they were 1 mol of fatty acids (based on the SODD saponifiable index) to 2.5 mol isoamyl alcohol, 45 °C, and 6 wt.% enzymes (enzyme mass/SODD mass). The effect of the water content of the reactional medium was also studied, with two conditions of molecular sieve ratio (molecular sieve mass/SODD mass) selected as 39 wt.% (almost anhydrous reaction medium) and 9 wt.%. Ester yields of around 50 wt.% and 70 wt.% were reached after 50 h reaction, respectively. The reaction products containing 43.7 wt.% and 55.2 wt.% FAIE exhibited viscosity indices of 175 and 163.8, pour points of -6 °C and -9 °C, flash points of 178 and 104 °C, and low oxidative stability, respectively. Their properties (mainly very high viscosity indices) make them suitable to be used as base stocks in lubricant formulation industries.

Immobilization of Eversa Lipases on Hydrophobic Supports for Ethanolysis of Sunflower Oil Solvent-Free

Lipases are an important group of biocatalysts for many industrial applications. Two new commercial low-cost lipases Eversa® Transform and Eversa® Transform 2.0 was immobilized on four different hydrophobic supports: Lewatit-DVB, Purolite-DVB, Sepabeads-C18, and Purolite-C18. The performance of immobilized lipases was investigated in the transesterification of sunflower oil solvent-free in an anhydrous medium. Interesting results were obtained for both lipases and the four supports, but with Sepabeads support the lipases Eversa showed high catalytic activity. However, the more stable and efficient derivative was Eversa® Transform immobilized on Sepabeads C-18. A 98 wt% of ethyl ester of fatty acid (FAEE) was obtained, in 3 h at 40ºC, ethanol/sunflower oil molar ratio of 3:1 and a 10 wt% of the immobilized biocatalyst. After 6 reaction cycles, the immobilized biocatalyst preserved 70 wt% of activity. Both lipases immobilized in Sepabeads C-18 were highly active and stable in the presence of ethanol. The immobilization of Eversa Transform and Eversa Transform 2.0 in hydrophobic supports described in this study appears to be a promising alternative to the immobilization and application of these news lipases still unexplored.

Performance of Liquid Eversa on Fatty Acid Ethyl Esters Production by Simultaneous Esterification/Transesterification of Low-to-High Acidity Feedstocks

Liquid Eversa was evaluated in hydrolysis of acylglycerols from soybean oil deodorizer distillate (SODD), as well as simultaneous esterification/transesterification of SODD with low-to-high free fatty acids (FFAs) content using ethanol as acyl acceptor. Hydrolysis of SODD at mild temperature (37 °C) and without pH control (water:SODD mass ratio of 4:1) increased its FFAs content from 17.2 wt.% to 72.5 wt.% after 48 h reaction. A cold saponification of SODD allowed a saponification phase (SODD-SP) to be recovered with 93 wt.% saponification index and 2.25 wt.% FFAs content, which was used to find the experimental conditions for simultaneous esterification/transesterification reactions by experimental design. Temperature of 35 °C, enzyme concentration of 8.36 wt.%, and molar ratio of 3.64:1 (ethanol:SODD-SP) were found as the best conditions for fatty acid ethyl esters (FAEEs) production from SODD-SP (86.56 wt.% ester yield after 23 h reaction). Under the same reaction conditions, crude SODD (17.2 wt.% FFAs) and hydrolyzed SODD (72.5 wt.% FFAs) yielded products containing around 80 wt.% FAEEs. Caustic treatment could increase the ester content to around 90 wt.% and reduce the FFAs content to less than 1 wt.%. Our results show the good performance of liquid Eversa in aqueous (hydrolysis reactions) and organic (esterification/transesterification reactions) media.

Biodiesel from oil produced in vegetative tissues of biomass - A review

Biodiesel is a green, renewable alternative to petroleum-derived diesel. However, using vegetable oil for biodiesel production significantly challenges the food security. Progress in metabolic engineering, understanding of lipid biosynthesis and storage have enabled engineering of vegetative tissues of plants such as sugarcane, sorghum, and tobacco for lipid production. Such sources could be cultivated on land resources, which are currently not suitable for row crops. Besides achieving significant lipid accumulation, it is imperative to maintain the fatty acid and lipid profile ideal for biodiesel production and engine performance. In this study, genetic modifications used to induce lipid accumulation in transgenic crops and the proposed strategies for efficient recovery of oil from these crops have been presented. This paper highlights that lipids sourced from vegetative biomass in their native form would pose significant challenges in biodiesel production. Therefore, different strategies have been presented for improving feedstock quality to achieve high-quality biodiesel production.

Effect of Concentrated Salts Solutions on the Stability of Immobilized Enzymes: Influence of Inactivation Conditions and Immobilization Protocol

This paper aims to investigate the effects of some salts (NaCl, (NH₄)₂SO₄ and Na₂SO₄) at pH 5.0, 7.0 and 9.0 on the stability of 13 different immobilized enzymes: five lipases, three proteases, two glycosidases, and one laccase, penicillin G acylase and catalase. The enzymes were immobilized to prevent their aggregation. Lipases were immobilized via interfacial activation on octyl agarose or on glutaraldehyde-amino agarose beads, proteases on glyoxyl agarose or glutaraldehyde-amino agarose beads. The use of high concentrations of salts usually has some effects on enzyme stability, but the intensity and nature of these effects depends on the inactivation pH, nature and concentration of the salt, enzyme and immobilization protocol. The same salt can be a stabilizing or a destabilizing agent for a specific enzyme depending on its concentration, inactivation pH and immobilization protocol. Using lipases, (NH₄)₂SO₄ generally permits the highest stabilities (although this is not a universal rule), but using the other enzymes this salt is in many instances a destabilizing agent. At pH 9.0, it is more likely to find a salt destabilizing effect than at pH 7.0. Results confirm the difficulty of foreseeing the effect of high concentrations of salts in a specific immobilized enzyme.

Microbial biodiesel production from industrial organic wastes by oleaginous microorganisms: Current status and prospects

This review aims to encourage the technical development of microbial biodiesel production from industrial-organic-wastes-derived volatile fatty acids (VFAs). To this end, this article summarizes the current status of several key technical steps during microbial biodiesel production, including (1) acidogenic fermentation of bio-wastes for VFA collection, (2) lipid accumulation in oleaginous microorganisms, (3) microbial lipid extraction, (4) transesterification of microbial lipids into crude biodiesel, and (5) crude biodiesel purification. The emerging membrane-based bioprocesses such as electrodialysis, forward osmosis and membrane distillation, are promising approaches as they could help tackle technical challenges related to the separation and recovery of VFAs from the fermentation broth. The genetic engineering and metabolic engineering approaches could be applied to design microbial species with higher lipid productivity and rapid growth rate for enhanced fatty acids synthesis. The enhanced in situ transesterification technologies aided by microwave, ultrasound and supercritical solvents are also recommended for future research. Technical limitations and cost-effectiveness of microbial biodiesel production from bio-wastes are also discussed, in regard to its potential industrial development. Based on the overview on microbial biodiesel technologies, an integrated biodiesel production line incorporating all the critical technical steps is proposed for unified management and continuous optimization for highly efficient biodiesel production.

Immobilization of Eversa® Transform via CLEA Technology Converts It in a Suitable Biocatalyst for Biolubricant Production Using Waste Cooking Oil

The performance of the previously optimized magnetic cross-linked enzyme aggregate of Eversa (Eversa-mCLEA) in the enzymatic synthesis of biolubricants by transesterification of waste cooking oil (WCO) with different alcohols has been evaluated. Eversa-mCLEA showed good activities using these alcohols, reaching a transesterification activity with isoamyl alcohol around 10-fold higher than with methanol. Yields of isoamyl fatty acid ester synthesis were similar using WCO or refined oil, confirming that this biocatalyst could be utilized to transform this residue into a valuable product. The effects of WCO/isoamyl alcohol molar ratio and enzyme load on the synthesis of biolubricant were also investigated. A maximum yield of around 90 wt.% was reached after 72 h of reaction using an enzyme load of 12 esterification units/g oil and a WCO/alcohol molar ratio of 1:6 in a solvent-free system. At the same conditions, the liquid Eversa yielded a maximum ester yield of only 34%. This study demonstrated the great changes in the enzyme properties that can be derived from a proper immobilization system. Moreover, it also shows the potential of WCO as a feedstock for the production of isoamyl fatty acid esters, which are potential candidates as biolubricants.

Biodiesel production from heterotrophic oleaginous microalga Thraustochytrium sp. BM2 with enhanced lipid accumulation using crude glycerol as alternative carbon source

Aiming to improve the economy and sustainability of biodiesel production, the scale-up of lipid production by heterotrophic Thraustochytrium sp. BM2 utilizing crude glycerol as a low cost carbon source was optimized in stirred tank fermenter. The issues of impurities such as excess ions, methanol, soap and other organic impurities as well as different pretreatment techniques were explored and tackled for industrial application of crude glycerol as carbon source. For process engineering strategies to enhance lipid production, semi-batch operation outperformed fed-batch cultivation and achieved higher lipid yield and overall lipid productivity primarily due to shorter fermentation time. The two-step esterification/transesterification method achieved high fatty acid methyl ester (FAME) conversion rate up to 91.8%, which was two to three folds higher compared with the one-step process.