Continuous Lipase‐Catalyzed Alcoholysis of Sunflower Oil: Effect of Phase‐Equilibrium on Process Efficiency

Abstract

Phase-equilibrium diagrams of biodiesel synthesis substrate (oil/alcohol/alkyl esters) and product (alkyl esters/glycerol/alcohol) mixtures containing methanol, ethanol and propanol, respectively, were used for the identification of those composition ratios leading to mixture homogeneity. Based on the diagrams, complete conversion of the substrate oil contained in a sunflower oil/ ethanol/ethyl ester mixture at a weight ratio of 7.6:11.4:81.0 resulted in the generation of an amount of glycerol capable of remaining in solution in the product mixture. In contrast, complete conversion using a mixture of a lower alcohol and ethyl ester content (19.0:6.0:75.0) leads to the separation of phases. A continuous reactor charged with Lypozyme TL-IM and fed with the former mixture showed constant conversion and productivity with time, whereas process efficiency was found to decrease drastically when the latter mixture was fed. When a sunflower oil/isopropanol/isopropyl ester mixture at a weight ratio of 35:35:30 was fed in the reactor charged with Novozym 435, the output glycerol concentration was equivalent to that theoretically expected. In contrast, feeding a sunflower oil/ethanol/ethyl ester mixture of equal proportions as above, the glycerol concentration was lower than expected, suggesting the occurrence of glycerol adsorption on the enzyme support.

Enzymatic synthesis of ethyl esters from waste oil using mixtures of lipases in a plug‐flow packed‐bed continuous reactor

“…In the studies in which a single lipase was employed, the results obtained showed high reaction yield. 40,43,44 However, the operating times were, in general, lower than the one obtained in the current research.…”

Production of biodiesel catalyzed by lipase from Thermomyces lanuginosus in its soluble form

“…Considering these drawbacks, several studies suggest the use of lipases for enzymatic transesterification of triglycerides as an interesting alternative to the alkaline process . Compared to the conventional reaction of biodiesel production, the enzymatic route is considered a “greener reaction” due to its environmental benefits, since there is no generation of alkaline wastewater, as well as washing steps for catalyst removal being unnecessary . In addition, this technology has benefits such as production of a high purity biodiesel, easy separation of products and byproducts from the reaction, mild reaction conditions of temperature and pressure, and production of a glycerin with minimum content of contamination by the catalyst .…”

Techno-Economic Performance of Different Technological Based Bio-Refineries for Biofuel Production

“…This might be due to the lower amount of undissolved alcohol in the substrate when we use ethanol than methanol because it is much amount of undissolved alcohol that inhibits the enzyme activity [57]. Thus, since ethanol is more soluble in oil than methanol [58], enzyme inhibition effect is very low when we use ethanol than methanol. Cervero' et al [25] also indicated that at maximum reaction time, the conversion of soybean oil to biodiesel was almost similar for both single step and multiple step addition of ethanol to the reaction.…”