Development of a green integrated process for biodiesel esters production: Use of fermented macaúba cake as biocatalyst for macaúba acid oil transesterification

Abstract

AbstractIn this study, a new green integrated process for biodiesel ester production was developed, consisting of the enzymatic transesterification of acid oil from macaúba palm tree (Acrocomia aculeata) catalyzed by dry fermented solid (DFS) with lipase activity, which was obtained from solid‐state fermentation (SSF) of macaúba cake. Analysis of statistical experimental designs showed that nitrogen supplementation of macaúba cake improved production of lipases displaying esterification capacity by Rhizomucor miehei. The conditions chosen to produce R. miehei DFS were cake supplementation with 2 wt% urea, 60 wt% of initial moisture during 48 h of fermentation at 40°C. DFS showed, by zymography assays, at least one enzyme that was different from those that are present in the commercial lipase of R. miehei. Furthermore, DFS was used in transesterification reactions between macaúba acid oil and alcohol (methanol or ethanol), and the ester content obtained was 92%. This is the first time that this integrated process using low‐cost biocatalysts and a low‐value oil derived from the processing of the same fruit was used for biodiesel ester production, reducing costs and logistic constraints, and optimizing the raw material utilization.