Detoxification of Molasses and Production of Mycelial Mass and Valuable Metabolites by Morchella Species

Marianna Dedousi,Eirini-Maria Melanouri,Panagiota Diamantopoulou,Katerina Fourtaka,Seraphim Papanikolaou,Ilias Diamantis,Dimitrios Argyropoulos,Charoula Psallida

doi:10.3390/app11209481

Marianna Dedousi, Eirini-Maria Melanouri + Show 6 more

Open Access

https://doi.org/10.3390/app11209481

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Abstract

Edible wild ascomycetes Morchella rotunda, M. vulgaris and M. conica were cultivated in liquid static and agitated flasks of sucrose and molasses substrates with a C/N ratio of 20 and 25. The impact of four substrates on the production and quality characteristics of morels was examined. Evaluation included determination of the dry mycelial mass, intra-cellular (IPS) and extra-cellular (EPS) polysaccharides, total phenolic (TPC) and antioxidant (TAC) components, proteins, as well as the degree of phenolic content reduction and decolorization of molasses. The influence of agitation conditions was also evaluated. Results showed that substrate consumption, biomass formation and secondary metabolites production were substrate, species, and C/N ratio dependent. Among species, M. conica achieved the maximum biomass (18.16 g/L) and IPS (4.8 g/L) production and significant phenolic reduction (56.6%) and decolorization (26.7%). The maximum EPS (3.94 g/L) was noted by M. rotunda, whereas TPC (32.2 mg/g), TAC (6.0 mg/g) and cellular protein (7.6% w/w) were produced in sufficient amounts. These results strongly support the use of Morchella mushrooms as a biological detoxification agent of molasses in liquid fermentations and indicate their nutritional and medicinal value.

Highlights

Edible fungi consumed fresh or processed are becoming more and more vital in the human diet due to their unique dietary and medical properties
The most important characteristic was total sugars concentration (TS) that ranged between 510–530 g/L and a total phenolic compound of 33.25 g/L
Biomass (X, g/L) production was significantly enhanced when Morchella species were cultivated on molasses

Summary

Introduction

Edible fungi consumed fresh or processed are becoming more and more vital in the human diet due to their unique dietary and medical properties. Morels (Morchella spp., Pezizales, Ascomycota) are among the most known edible wild ascomycetes and they have attracted research interest due to their commercial value, medicinal properties, and unique taste and flavor [8]. Their habitat in combination with various biochemical pathways and the mycelial mass are responsible for their appearance, mainly their black or yellow color [9], which affects their growth and metabolite production [10]. The difficulties on the cultivation of morels in lignocellulosic wastes like saprophytic mushroom species (e.g., Pleurotus spp.) have led some researchers on their growth in liquid cultures aiming at the production of edible mycelium and the synthesis of secondary metabolites like polysaccharides, proteins, lipids, etc. According to literature results in submerged cultures, the production of mycelial mass, the secondary metabolites, as well as substrate consumption are largely affected by multiple cultivation parameters, including the medium composition (carbon and nitrogen sources used, C/N ratio) [17,20,21,22,23], cultivation conditions (temperature, pH, agitation) [23,24,25,26,27] and the type of species [10,21]

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