Enzymatic Biodiesel Synthesis by the Biphasic Esterification of Oleic Acid and 1-Butanol in Microreactors

Abstract

The enzymatic esterification of oleic acid and 1-butanol to butyl oleate was performed in an aqueous–organic system in capillary microreactors with various inner diameters operated under slug flow. The free Rhizomucor miehei lipase in the aqueous phase was used as a catalyst and n-heptane as the organic solvent. A close to 100% yield of butyl oleate could be achieved in the microreactor made of polytetrafluoroethylene within 30 min residence time at 30 °C. The reaction rate is well described by the existing kinetic model based on a Ping Pong Bi Bi mechanism with competitive inhibition of 1-butanol. This model was extended to describe the effect of the interfacial area and aqueous-to-organic flow ratio in microreactors. By performing the reaction at low aqueous-to-organic flow ratios in hydrophilic microreactors (e.g., made of stainless steel), the enzyme turnover number could be enhanced significantly, making it promising for process intensification.

The occurrence, enzymatic production, and application of ethyl butanoate, an important flavor constituent

“…In this type of system, water‐insoluble substrates are dissolved in the organic phase and the enzyme is placed in the aqueous phase 110 . The biphasic system has advantages such as making the water‐insoluble substrates to be soluble and accessible by enzyme, reducing substrate or product inhibition, minimizing the backward reaction by separating product in the organic phase, and easing product and enzyme recovery that ensures enzyme turnover numbers 16,78,111 …”

“…The temperature should be 50 to 60ºC, and on the meanwhile lots of by‐products are produced and additional stages are required for the separation and purification 13,14 . These processes are unhealthy and considered as environmentally unsafe 6,15,16 …”

“…13,14 These processes are unhealthy and considered as environmentally unsafe. 6,15,16 On the other hand, enzymatic production of flavor esters using natural substrates can be labeled as natural. 17 For enzyme catalysis, serine-histidine-aspartic acid/glutamic acid are the catalytic triads present in the active sites of enzymes such as lipases.…”

Experimental study and mass transfer modelling for extractive desulfurization of diesel with ionic liquid in microreactors

“…An effective way to enhance the mass transfer rate is to increase the interfacial area between phases, which is exactly one of the most prominent characteristics of microreactor technology. Particularly when operating under segmented flow pattern, where both phases are present as discrete segments (i.e., droplets and slugs) with sub-millimeter scale in the miniaturized and confined space, microreactors offer not only large interfacial area and short diffusion distance, but also additional internal circulation that is critical for further enhancing mixing and mass transfer [20][21][22][23]. Previous studies on using ILs or other highly viscous liquids (e.g.…”

Sulfonic Acids Supported on UiO-66 as Heterogeneous Catalysts for the Esterification of Fatty Acids for Biodiesel Production

“…More importantly, fatty acid esters, including fatty acid methyl esters, fatty acid ethyl esters and fatty acid butyl esters, are a class of biodiesel, used as a renewable energy source [6][7][8]. One of the main processes to produce fatty acid esters (biodiesel) is the esterification of fatty acids with short chain alcohols (e.g., methanol, ethanol, butanol) [9,10].…”