Synthesis of Ethylic Esters for Biodiesel Purposes Using Lipases Naturally Immobilized in a Fermented Solid Produced Using Rhizopus microsporus

Abstract

We grew Rhizopus microsporus CPQBA 312-07 DRM in solid-state fermentation on a 1:1 mixture, by mass, of sugarcane bagasse and sunflower seed meal, to produce a fermented solid containing lipases (tricaprylin-hydrolyzing activity of 91 U g −1 ) and then used this fermented solid to catalyze the ethanolysis of corn oil. A 2 3 factorial design was used to optimize the reaction using n-heptane as the solvent. The best conversion was 91% at 48 h, obtained at 44 °C, with a molar ratio of ethanol/oil of 3:1 and the addition of 1.32 g of fermented solids/15 mL of reaction medium. Using these optimized conditions, we studied the effect of increasing the concentration of the reactants in the medium and even the use of a solvent-free system. In these systems, conversions were quite poor when the ethanol was added in a single aliquot at the start of the reaction. However, when the ethanol was added stepwise, with three equal aliquots added at 0, 24, and 48 h, promising conversions were obtained, including an ester yield of 51% at 72 h in the solvent-free medium. An improved fermented solid (tricaprylin-hydrolyzing activity of 183 U g −1 ) was then used to improve the production of ethylic esters in solvent-free medium, with an ester yield of 68% being obtained at 72 h. These results are promising and justify further optimization studies.

Production of pectinases by solid-state fermentation of a mixture of citrus waste and sugarcane bagasse in a pilot-scale packed-bed bioreactor

“…With respect to the direct addition of fermented solids with enzyme activity in subsequent processes, this has only been done with lipases: several groups have used "lipolytic fermented solids" to produce biodiesel through the esterification of fatty acids or the transesterification of triacylglycerols, using short chain alcohols [10,[15][16][17][18][19][20][21]. However, this strategy has not previously been used for the hydrolysis of pectin by pectinases.…”

Enzyme-Catalyzed Synthesis and Kinetics of Ultrasonic-Assisted Methanolysis of Waste Choice White Grease for Fatty Acid Methyl Ester Production

“…3,5 In fact, conventional approaches of the enzyme-catalyzed transesterification method, which has been reported as a suitable technique for these types of feedstocks, are timeconsuming. 6,7 For instance, Zago et al 8 studied the synthesis of ethylic esters for biodiesel purposes using lipases naturally immobilized in a fermented solid produced using Rhizopus microsporus. The authors reported the best conversion to be 91% at 48 h reaction time, obtained at 44°C, with a molar ratio of ethanol/oil of 3:1 using a rotary shaker at 180 rpm.…”

Analysis of multiphasic behavior during the ethyl esterification of fatty acids catalyzed by a fermented solid with lipolytic activity in a packed-bed bioreactor in a closed-loop batch system

“…Rather, they attributed it to adsorption of 1-phenylethanol onto the surface of the resin, such that the microenvironment of the esterase contained higher 1-phenylethanol concentrations than those of the bulk reaction medium. Such a study of the composition of the sorbed medium has not been undertaken previously with systems involving fermented solids with lipase activity, neither in our own work [2,[13][14][15], nor in the work of Liu et al [16,17], who also used a fermented solid based on sugarcane bagasse and sunflower seed, nor in the work of Aguieiras et al [1], who used a fermented solid based on babassu cake. However, the question of the microenvironment of the lipase has been addressed in other systems involving esterification of fatty acids using immobilized lipases, as we discuss below.…”

“…Also, the formation of a sorbed phase has been observed in systems involving lipases immobilized on commercial supports: Krause and Fieg [12] showed that the nonpolar organic phase sorbed onto poly-(methyl methacrylate) beads used in Novozym 435, while Sandoval et al [10] showed that water sorbed onto the macroporous anionic resin (Duolite A568) used in Lipozyme Ò . However, the sorption of medium components has not previously been studied in systems involving fermented solids with lipolytic activity, neither in our own work [2,[13][14][15] nor that of Liu et al [16,17] and Aguieiras et al [1]. In the present work, we investigate the sorption of the reaction medium onto our fermented solid, and also the phase behavior of the bulk reaction medium, in order to understand the effects of these phenomena on the esterification reaction.…”