Adsorption of extracellular lipase in a packed-bed reactor: an alternative immobilization approach.

In light of the growing demand for novel biocatalysts and enzyme production methods, this study aimed to evaluate the potential of Aspergillus tubingensis for producing lipase under submerged culture investigating the influence of culture time and inducer treatment. Moreover, this study also investigated conditions for the immobilization of A. tubingensis lipase by physical adsorption on styrene-divinylbenzene beads (Diaion HP-20), for these conditions to be applied to an alternative immobilization system with a packed-bed reactor. Furthermore, A. tubingensis lipase and its immobilized derivative were characterized in terms of their optimal ranges of pH and temperature. A. tubingensis was shown to be a good producer of lipase, obviating the need for inducer addition. The enzyme extract had a hydrolytic activity of 23 U mL-1 and achieved better performance in the pH range of 7.5 to 9.0 and in the temperature range of 20 to 50 °C. The proposed immobilization system was effective, yielding an immobilized derivative with enhanced hydrolytic activity (35 U g-1), optimum activity over a broader pH range (5.6 to 8.4), and increased tolerance to high temperatures (40 to 60 ℃). This research represents a first step toward lipase production from A. tubingensis under a submerged culture and the development of an alternative immobilization system with a packed-bed reactor. The proposed system holds promise for saving time and resources in future industrial applications.

Solvent-Free Enzymatic Synthesis of Dietary Triacylglycerols from Cottonseed Oil in a Fluidized Bed Reactor.

The synthesis of structured lipids with nutraceutical applications, such as medium-long-medium (MLM) triacylglycerols, via modification of oils and fats represents a challenge for the food industry. This study aimed to synthesize MLM-type dietary triacylglycerols by enzymatic acidolysis of cottonseed oil and capric acid (C10) catalyzed by Lipozyme RM IM (lipase from Rhizomucor miehei) in a fluidized bed reactor (FBR). After chemical characterization of the feedstock and hydrodynamic characterization of the reactor, a 22 central composite rotatable design was used to optimize capric acid incorporation. The independent variables were cycle number (20-70) and cottonseed oil/capric acid molar ratio (1:2-1:4). The temperature was set at 45 °C. The best conditions, namely a 1:4 oil/acid molar ratio and 80 cycles (17.34 h), provided a degree of incorporation of about 40 mol%, as shown by compositional analysis of the modified oil. Lipozyme RM IM showed good operational stability (kd = 2.72 × 10-4 h-1, t1/2 = 2545.78 h), confirming the good reuse capacity of the enzyme in the acidolysis of cottonseed oil with capric acid. It is concluded that an FBR configuration is a promising alternative for the enzymatic synthesis of MLM triacylglycerols.

Evaluation of Candida rugosa Lipase Immobilized on Magnetic Nanoparticles in Enzymatic/Chemical Hydroesterification for Biodiesel Production.

This study aimed to (i) prepare functionalized maghemite nanoparticles for immobilization of Candida rugosa lipase (CRL) by covalent binding, (ii) evaluate the application of the immobilized derivative in the hydrolysis of waste cooking oil (WCO) to fatty acids, and (iii) assess the potential of the hydrolyzed material for biodiesel production by hydroesterification. Maghemite (γFe2O3) obtained by precipitation of Fe3Cl2 with NH4OH served as an efficient support for covalent immobilization of CRL. Fourier-transform infrared spectroscopy and hydrolytic activity analysis indicated that CRL was covalently immobilized on the surface of the maghemite support. The derivative showed an activity of 166.62 ± 8 U g-1 in WCO hydrolysis at 40 °C and pH 6. Scanning electron microscopy revealed that, after lipase immobilization, nanoparticles became more dispersed, which is advantageous for biocatalysis reactions, as it increases the contact area with the substrate. WCO hydrolysis afforded 96 ± 0.2 wt% free fatty acids. In the second step, free fatty acids were subjected to chemical esterification with sulfuric acid, affording 94.4 ± 0.02 wt% fatty acid methyl esters (biodiesel). The findings of this study contribute to the field of biotechnology and may promote the development of enzymatic technologies for the synthesis of products of economic and social interest.

Improved synthesis of dietary triglycerides by using lipase supported on clay carriers.

BACKGROUND: In the search for healthier and more functional foods, dietary triglycerides (TAGs) have played a prominent role in the food industry. The objective of this work was to evaluate new clay supports to immobilize lipase from Rhizopus oryzae and use it in the synthesis of TAGs. MAIN METHODS AND MAJOR RESULTS: The immobilization of lipase by physical adsorption was carried out, determining the hydrolytic activity, esterification, immobilization yield, thermal stability, and kinetic and thermodynamic parameters. Afterwards, acidolysis was carried out and the product characterized as to composition, acidity index (AI), peroxide index (PI), and analysis of the sn-2 position. The mean hydrolytic activity of free lipase was 23,568.43 ± 559.20 U g-1 and for lipase immobilized in acidified kaolin and diatomite, 1409.04 ± 51.07 and 1235.67 ± 9.56 U g-1 ; immobilization yield of 23.78% and 20.21% and esterification activity of 1827.99 and 1722.66 U g-1 , respectively, maintaining more than 60% of the relative activity after 8 h of incubation at different temperatures. The reaction using the derivative immobilized in acidified diatomite resulted in the degree of incorporation (DI) 41.53% ± 3.99%. CONCLUSIONS AND IMPLICATIONS: From the results, the potential of diatomite and kaolin as support in the immobilization of lipase for the synthesis of dietary TAGs was verified.

Enzymatic synthesis of structured lipids from grape seed (Vitis vinifera L.) oil in associated packed bed reactors.

Triacylglycerols (TAGs) can be modified to increase the absorption of fatty acids, prevent obesity, and treat fat malabsorption disorders and metabolic diseases. Medium-long-medium (MLM)-type TAGs, which contain medium-chain fatty acids in the sn-1 and sn-3 positions of the glycerol backbone and a long-chain fatty acid in the sn-2 position, show particularly interesting nutritional characteristics. This study aimed to synthesize MLM-type TAGs by enzymatic acidolysis of grape seed oil with medium-chain capric acid (C10:0) in associated packed bed reactors. The reaction was carried out during 120 H, at 45 °C, using lipase from Rhizomucor miehei (Lipozyme® RM IM). The residence time distribution of reagents in the reactor was quantified to evaluate the reactor behavior and to diagnose the existence of preferential paths. The reaction progress was monitored by analyzing TAG composition and, at the steady state (after 48 H of reaction), the incorporation degree achieved a value of 39.91 ± 2.77%. To enhance the capric acid incorporation, an acidolysis reaction in associated packed bed reactors was performed. The results showed a good operational stability of the biocatalyst, revealing values of half-life 209.64 H, 235.63 H of packed bed and associated packed bed reactor, respectively, and a deactivation coefficient 0.0061 H-1 .

Microbial lipase: a new approach for a heterogeneous biocatalyst.

Lipases are enzymes employed in several industrial process and their applicability can be increased if these biocatalysts are in the immobilize form. The objective of this work was to study the immobilization of lipase produced by submerged cultivation of Aspergillus sp. by hydrophobic interaction, evaluating its stability and reuse capacity. The immobilization process on octyl-sepharose (C8) and octadecyl-sepabeads (C18) carriers was possible after the removal of oil excess presented in the fermented broth. The results showed that the enzyme was isolated and concentrated in octyl-sepharose with 22% of the initial activity. To increase the amount of enzyme adsorbed on the carrier, 4 immobilization cycles were performed in a row, on the same carrier, with a final immobilization yield of 151.32% and an increase in the specific activity of 136%. The activity test with immobilized lipase showed that the immobilized enzyme maintained 75% of the initial activity after 20 cycles.

Assessment of pectinase-producing fungi isolated from soil and the use of orange waste as a substrate for pectinase production

Pectinases are important enzymes not only for their potential applications in different industries such animal feed, agricultural, textile, beverage, food processing, oil extraction, etc. Ten fungal species were isolated from the soil and screened for production of pectinase enzyme by using the pectin agar medium. Pectinolytic enzymes synthesis were attained at a temperature of 30 °C and activities were determined after a seven-days culture of Aspergillus sp. 391 and Aspergillus sp. 031, in a basic medium containing 2% citrus pectin and as the sole carbon source. The extract enzymatic showed an optimum activity for exo-polygalacturonase (PG) and pectin lyase (PNL) against galacturonic acid and pectin at pH 4.5 and 5.5, respectively. There were variations in PG and PNL enzymes levels produced in culture filtrates obtained of Aspergillus sp. 391 with addition of citrus waste (2.0 and 4.0 % w/v) to the medium. Maximum activity for PNL activity was observed in the medium containing 5% pectin or 4% citrus waste, as sole carbon source, after 7 days of growth. The results showed that the isolate Aspergillus sp. 391 is a promising for pectinolytic enzymes production at the industrial level.(AU)

Screening of food grade lipases to be used in esterification and interesterification reactions of industrial interest.

Seven food grade commercially available lipases were immobilized by covalent binding on polysiloxane-polyvinyl alcohol (POS-PVA) hybrid composite and screened to mediate reactions of industrial interest. The synthesis of butyl butyrate and the interesterification of tripalmitin with triolein were chosen as model reactions. The highest esterification activity (240.63 microM/g min) was achieved by Candida rugosa lipase, while the highest interesterification yield (31%, in 72 h) was achieved by lipase from Rhizopus oryzae, with the production of about 15 mM of the triglycerides C(50) and C(52). This lipase also showed a good performance in butyl butyrate synthesis, with an esterification activity of 171.14 microM/g min. The results demonstrated the feasibility of using lipases from C. rugosa for esterification and R. oryzae lipase for both esterification and interesterification reactions.