This study aimed to employ elephant grass (Pennisetum purpureum) as a lignocellulosic support for lipase immobilization, with the goal of developing a sustainable biocatalyst for biodiesel synthesis. Initially, the material in its in natura form was washed with distilled water to remove impurities, dried in an oven at 60 °C, ground in a knife mill, sieved to the desired particle size (42–80 mesh), and chemically characterized regarding cellulose, hemicellulose, lignin, and ash content. Subsequently, Burkholderia cepacia lipase (BCL) was immobilized by physical adsorption, and the resulting biocatalyst was characterized in terms of biochemical properties (pH and temperature), kinetic parameters (Km and Vmax), thermal stability (45 °C), and morphology. Morphological analyses revealed a rough structure of the support and the adhesion of the enzyme to its surface. Biochemical evaluations indicated maximum hydrolytic activity at pH 7.5 and temperatures between 45–60 °C. The kinetic parameters Km and Vmax were 1689.71 ± 261.42 mM and 4641.50 ± 333.24U g-1, respectively, and thermal stability was evaluated at 45 °C, resulting in a half-life of 40.1 h. The catalytic performance was evaluated in the transesterification reaction of babassu oil with ethanol (molar ratio 1:12, 170 rpm, 45 °C, 72 h), resulting in 100% conversion to ethyl esters and a viscosity of 4.7 mm2 s-1, within the limits established by official standards. Furthermore, the operational stability study revealed a half-life of 239 h for the biocatalyst, demonstrating that elephant grass is a promising support for lipase immobilization, representing a viable and sustainable alternative to synthetic supports due to its abundance, biodegradability, and ease of availability.
Theodoro et al. (Sat,) studied this question.