Limonene Biotransformation Mediated by Filamentous Fungi from the Brazilian Amazon

Fungal biotransformation is a relevant strategy to obtain high-added value natural compounds under controlled environmentally friendly conditions. R-(+)-limonene is the main component of the orange peel oil, which is available in large amounts, at low cost, and can be employed in biotransformation processes as a precursor of different value-added aroma compounds. The goal of the study was to evaluate the ability of filamentous fungi from the Brazilian Amazon to biotransform R-(+)-limonene. The fungal biotransformation assays were executed using forty-seven filamentous fungi and executed in flasks containing the substrate R-(+)-limonene in mineral medium for 120 h. In this study, nine endophytic fungi, two macrofungi, and one aquatic fungus were considered potential candidates for limonene biotransformation, since they eventually accumulated interesting compounds after 120 h of reaction. However, only Pestalotiopsis mangiferae LaBMicrA-505 was the most promising endophytic fungi found in the screening, due to its capacity to use all the R-(+)-limonene as the single carbon and energy source in a mineral medium, with the main oxygenated derivatives being limonene-1,2-diol (74.13 ± 0.81%) and limonene-1,2-epoxide (1.88 ± 0.08%), which were accumulated after 72 h of reaction. These achievements are important and support the development of the production of natural aromas and demonstrate the potential of using these wild Amazonian fungi as new biocatalysts.