Producing high value aroma compounds by whole-cell biocatalysis using Aspergillus niger LBM055

Abstract

The aims of this article were to optimize and assay the production of high value aroma compounds at a bench-scale by the bioconversion capacity of Aspergillus niger LBM055 strain using R-limonene as platform chemical. Temperature, pH and agitation effect on R-limonene bioconversion were evaluated. Optimal R-limonene bioconversion was met at 30.5 ∘C , 100 rpm and pH 6.2, meanwhile best yield of high molecular weights products was obtained at 28 ∘C , 100 rpm and pH 5.4. Conditions of best yield of high molecular weights were selected to apply them at a bench-scale bioreactor. α -pinene, β -pinene, citral, linalool, carvone, carveol and myrcene were identified. Also, a mixture of carvone, carveol and limonene oxide at a high concentration of 3.1 g/L, was identified by GC-MS analysis. Optimization analysis demonstrated that with the same substrate and fungal strain, it was possible to obtain different bioaromas compounds only by changing the operating conditions. Applying the operating parameters in a bench-scale bioreactor, a composite biofragrance of a terpene mixture, recognized by their citric, woody, floral and minty aromatic notes, was obtained. This study contributed to identified operational condition for the R-limonene bioconversion scale-up for the extension in the citrus industry value chain.