Biotransformation of 1,8-cineole by solid-state fermentation of Eucalyptus waste from the essential oil industry using Pleurotus ostreatus and Favolus tenuiculus

Abstract

Biotechnological conversion of low-cost agro-industrial by-products, such as industrial waste or terpenes from the distillation of essential oils from plants into more valuable oxygenated derivatives, can be achieved by using microbial cells or enzymes. In Argentina, the essential oil industry produces several tons of waste each year that could be used as raw materials in the production of industrially relevant and value-added compounds. In this study, 1,8-cineole, one of the components remaining in the spent leaves of the Eucalyptus cinerea waste, was transformed by solid-state fermentation (SSF) using the two edible mushrooms Pleurotus ostreatus and Favolus tenuiculus. As a result, two new oxygenated derivatives of 1,8-cineole were identified: 1,3,3-trimethyl-2-oxabicyclo [2.2.2]octan-6-ol and 1,3,3-trimethyl-2-oxabicyclo [2.2.2]octan-6-one. Additionally, changes in the relative percentages of other aroma compounds present in the substrate were observed during SSF. Both fungal strains have the ability to produce aroma compounds with potential applications in the food and pharmaceutical industries.

Upgrading the Nutritional Value of Rice Bran by Solid-State Fermentation with Pleurotus sapidus

“…P. sapidus was cultivated by SSF using rice bran (RB) as substrate and contained in 250 mL flasks as previously described [3,12]. The flasks were prepared by mixing RB (10 g) with water (12 mL).…”

“…Different types of agri-food industry side-streams have been used for SSF to produce enzymes, bioactive compounds, high-quality animal feed supplements, and flavors, among others. Besides, an increasing number of organisms have been used for SSF, like bacteria, yeast, ascomycetes, and basidiomycetes [2][3][4].…”

“…After fermentation, an increase in nutrient availability, biosurfactant content, and mono-and polyunsaturated fatty acid content was observed. The same process also allowed the release and transformation of phenolic (e.g., ferulic acid) and volatile compounds-a fact that further enhances the potential benefits of the fermented substrates [2][3][4]6,8,9].…”

“…Pleurotus species are edible fungi that belong to the basidiomycota division; they can be grown in a wide variety of plant-based substrates [2,3,10]. This work focuses on the fermentation of rice bran by P. sapidus, which is a well-known edible fungus that is easy to cultivate in SSF, provides high nutritional quality food, and produces fascinating enzymes and metabolites [3,[10][11][12].…”

Solid-State Fermentation as a Novel Paradigm for Organic Waste Valorization: A Review

“…Comparative analysis of production of aroma compounds by Pleurotus ostreatus JMO 95 fruit body and its mycelium obtained under SmF and SSF (agar and sugarcane bagasse) showed that the main aromatic compounds octan-3-one (sweet and fruity odor), octan-3-ol (hazelnut and sweet herbaceous odor) were produced in the same proportions on the agar surface and on the solid support culture. However, in liquid fermentation, the aromatic intensity produced was very low [205].The cultivation of P. ostreatus and Favolus tenuiculus by SSF using eucalyptus waste from the essential oil industry as a substrate was able to transform 1,8-cineole to new aroma compounds which were 1,3,3-trimethyl-2-oxabicyclo[2.2.2]octan-6-ol and 1,3,3-trimethyl-2-oxabicyclo[2.2.2] octan-6-one [206].…”