Produção de biodiesel utilizando a lipase Thermomyces lanuginosus como catalisador

Abstract

With the inevitable decline in fossil fuel reserves, recent research has consolidated biodiesel as a promising source of energy, especially in the replacement of petroleum diesel. Several technologies have proven appropriate to produce the biofuel, among them the biotechnological route, where enzymes are employed as catalysts of the process. Many researches published in recent years have utilized the enzymatic route for biodiesel production employing polymeric supports for lipase immobilization and consequently to try to reuse it. However, this method makes the process more expensive, compromising its viability. In this sense, the liquid formulation of Thermomyces lanuginosus lipase arises as an alternative to the technique since it allows its use in a pure way in the reaction. This work proposes to investigate the utilization of the liquid formulation of the Thermomyces lanuginosus lipase (tradename CalleraTM Trans L), as a catalyst of a transesterification reaction to produce biodiesel. For this, through the use of experimental design, the influence in the biodiesel yield produced in the process of the main variables involved in the reaction was evaluated: reaction temperature (ranging from 25°C to 45°C), methanol to feedstock molar ratio (ranging from 3:1 to 6:1), enzyme load (ranging from 0,4% to 1,8%) and, subsequently with the optimized data, the influence of water addition in the reaction medium (ranging from 0% to 12%). In these procedures, degummed soybean oil was utilized as raw material of the reaction. Posteriorly, with the obtaining of the best reactional condition from the experimental design, it was evaluated the gradual replacement of soybean oil a feedstock of lower aggregate value – deacidified beef tallow - was evaluated in order to minimize production costs. The results obtained showed that the enzymatic route is able to reach high biodiesel yields. The variable “methanol excess” in the reaction medium was the one that had the greatest influence on the FAME yields obtained in the process since methanol is the main responsible for the denaturation and loss of the catalytic capacity of the lipase. On the other hand, the substitution of soybean oil for beef tallow resulted in an increase in the conversion of fatty acids, since the highest biodiesel yields were achieved when pure beef tallow was used as substrate of the enzymatic reaction (84,6% versus 73,1% of yield when only degummed soybean oil was used as feedstock). Therefore, the use of lipases in it soluble form as a catalyst for a transesterification reaction to produce biodiesel showed to be a satisfactory alternative to the more widespread production routes of the biofuel in question.