Patricia Bogalhos Lucente Fregolente

Monoglycerides and Diglycerides Synthesis in a Solvent-Free System by Lipase-Catalyzed Glycerolysis

Five lipases were screened (Thermomyces lanuginosus free and immobilized forms, Candida antarctica B, Candida rugosa, Aspergillus niger, and Rhizomucor miehei) to study their ability to produce monoglycerides (MG) and diglycerides (DG) through enzymatic glycerolysis of soybean oil. Lipase from C. antarctica was further studied to verify the enzyme load (wt% of oil mass), the molar ratio glycerol/oil, and the water content (wt% of glycerol) on the glycerolysis reaction. The best DG and MG productions were in the range 45–48% and 28–30% (w/w, based on the total oil), respectively. Using immobilized lipases, the amount of free fatty acids (FFA) produced was about 5%. However, the amount of FFA produced when using free lipases, with 3.5% extra water in the system, is equivalent to the MG yield, about 23%. The extra water content provides a competition between hydrolysis and glycerolysis reactions, increasing the FFA production.

Enzymatic hydrolysis of salmon oil by native lipases: optimization of process parameters

Tres lipases microbianas nativas (Aspergillus niger, Rhizopus javanicus e Penicillium solitum) foram utilizadas na hidrolise do oleo de salmao (teor de AGPI n-3 de 30,1%) com o objetivo de concentrar o conteudo de acidos graxos poliinsaturados n-3 (AGPI n-3) nos acilglicerois residuais. A metodologia de planejamento experimental e analise de superficie de resposta foi usada para se chegar as condicoes otimizadas de cada reacao enzimatica, utilizando as seguintes variaveis; temperatura (X 1 ), quantidade de lipase (X 2 ) e taxa de agua/oleo (X 3 ). Com base nos resultados do planejamento, a lipase de Aspergillus niger foi a mais eficiente na concentracao dos AGPI n-3, sendo que as condicoes otimas de reacao foram: concentracao de enzima de 500 U g -1 oleo, temperatura 45 °C e taxa de agua/oleo de 2:1 m/m apos 24 h de reacao. O grau de hidrolise (60%) conduziu a um aumento do conteudo de acido docosahexaenoico (DHA) de 14,4% para 34,0% (enriquecimento de 2,4 vezes) nos acilglicerois residuais apos a hidrolise do oleo de salmao. In an attempt to concentrate the content of n-3 polyunsaturated fatty acids (n-3 PUFA) in the residual acylglycerol, salmon oil (n-3 PUFA content of 30.1%) was hydrolyzed with three kinds of native microbial lipases (Aspergillus niger, Rhizopus javanicus and Penicillium solitum). For each lipase, a response surface methodology was used to obtain maximum PUFA content and to optimize the parameters of enzymatic reactions with respect to important reaction variables; temperature (X 1 ), amount of lipases (X 2 ) and water/oil ratio (X 3 ). Based on these results, optimal reaction conditions were established. Aspergillus niger lipase was the most effective in concentrating n-3 PUFA. The degree of hydrolysis (60%) led to an increase in the docosahexaenoic acid (DHA) content from 14.4% in the original oil to 34.0% (2.4-fold enrichment) in the residual acylglycerol under optimum conditions: enzyme concentration of 500 U g -1 oil, reaction temperature of 45 °C and water/oil mass rate of 2:1 (m/m) after 24 h reaction.

Screening of microbial lipases and evalutaion of their potential to produce glycerides with high gamma linolenic acid concentration

Gamma linolenic acid (GLA, 18:3, cis- 6,9,12- octadecatrienoic acid), an important compound in n- 6 eicosanoid family biosynthesis, occurs in the lipids of a few plant and microbial sources. This study focused on the screening of microbial strains with suitable lipase activity for enrichment of GLA by selective hydrolysis of the borage oil (21.6 % of GLA/total fatty acids). Firstly, 352 microrganisms were tested for their lipolytic capacity using screening techniques on agar plates containing borage oil, strains were then selected and screened for their activity (U/mg) using both submerged fermentation (SmF) and solid state fermentation (SSF). The rate of hydrolysis and the selective preference of these hydrolytic enzymes towards fatty acids, with a special focus on enrichment of GLA were studied and compared with those obtained by two commercially-available lipases. Only one of the lipases tested during this study displayed selectivity, discriminating the GLA during the hydrolysis reaction. Using the enzymatic extract from Geotrichum candidum as a biocatalyst of the reaction, it was possible to obtain a percentage of 41.7% of GLA in acylglycerols fraction when the borage oil was treated in a fixed-bed reactor for 24 hours at 30ºC.

A CAPE approach to gamma-Linolenic acid production via lipase-catalyzed enzymatic hydrolysis

Abstract In this work, a lipase-catalyzed selective enzymatic hydrolysis of the borage oil was carried out using commercial enzymes and native crude enzymatic extract from Brazil as biocatalysts for the reaction. Two crude enzymatic extracts home-produced and three commercial lipases were screened for concentrating γ-linolenic acid of the triacylglycerols in unhydrolyzed acylglycerols. The kinetics of enzymatic hydrolysis of borage oil using Geotrichum candidum lipase in a batch reactor has been investigated. This work also presents a systematic procedure for parameter estimation through of dynamic optimization implemented as a nonlinear programming problem. With the reaction rate, a simulator was developed to explore the possible operational strategies for a large-scale reactor. The proposed computer-aided tool was applied to optimize the parameter of Michaelis-Menten kinetic model.