Valorization of Agro-Industrial Wastes and Residues through the Production of Bioactive Compounds by Macrofungi in Liquid State Cultures: Growing Circular Economy

Abstract

Vast quantities of side streams produced worldwide by the agricultural and food industry present an environmental challenge and an opportunity for waste upcycling in the frame of the circular bioeconomy. Fungi are capable of transforming lignocellulosic residues and wastes into a variety of added-value compounds with applications in functional food products, pharmaceuticals, chemicals, enzymes, proteins, and the emerging sector of nutraceuticals. The liquid state culture of fungi is an efficient and potentially scalable and reproducible biotechnological tool that allows the optimized production of fungal metabolites. Particularly, the utilization of agro-industrial by-products, residues, and wastes as a substrate for the liquid culture of macrofungi is suggested as an attainable solution in the management of these streams, contributing to climate change mitigation. This review presents recently published literature in the field of liquid state cultures of macrofungi using agro-industrial side streams, the different substrates, methods, and factors affecting their growth and metabolite production, as well as their applications, focusing on the variety of natural valuable compounds produced.

Poly-Unsaturated Fatty Acids (PUFAs) from Cunninghamella elegans Grown on Glycerol Induce Cell Death and Increase Intracellular Reactive Oxygen Species

“…From the obtained results, it can be seen that TDCW production was almost equivalent, irrespective of the trial perform on glucose or glycerol, since, in both instances, X max concentration was achieved c. 330-360 h after inoculation, presenting similar values (≈13.5 g/L) for both trials (Figure 1a). Equally, the substrate assimilation rate was almost the same for the two substrates employed as carbon sources, in disagreement with most literature reports [3,29,[42][43][44][45] that indicate that for most higher (e.g., Ascomycetes/Basidiomycetes) or lower (e.g., Zygomycetes) fungi, glucose is considered by far to be a more adequate carbon source compared to glycerol, due to the poor regulation of the enzymes implicated in the uptake of glycerol by these very microorganisms [29,43,44].…”

“…From the obtained results, it can be seen that TDCW production was almost equivalent, irrespective of the trial perform on glucose or glycerol, since, in both instances, Xmax concentration was achieved c. 330-360 h after inoculation, presenting similar values (≈13.5 g/L) for both trials (Figure 1a). Equally, the substrate assimilation rate was almost the same for the two substrates employed as carbon sources, in disagreement with most literature reports [3,29,[42][43][44][45] that indicate that for most higher (e.g., Ascomycetes / Basidiomycetes) or lower (e.g., Zygomycetes) fungi, glucose is considered by far to be a more adequate carbon source compared to glycerol, due to the poor regulation of the enzymes implicated in the uptake of glycerol by these very microorganisms [29,43,44]. Moreover, it was with interest that, in the present investigation, significantly higher lipid production was observed to occur in the trial performed on glycerol (Lmax = 8.4 g/L, simultaneous lipid in TDCW = 62.7% w/w), compared to the experiment performed on glucose (Lmax = 7.0 g/L, simultaneous lipid in TDCW =51.4% w/w), demonstrating, once Moreover, it was with interest that, in the present investigation, significantly higher lipid production was observed to occur in the trial performed on glycerol (L max = 8.4 g/L, simultaneous lipid in TDCW = 62.7% w/w), compared to the experiment performed on glucose (L max = 7.0 g/L, simultaneous lipid in TDCW =51.4% w/w), demonstrating, once more, the suitability of glycerol as the implicated substrate in the conversions performed by C. elegans.…”

A sustainable bioprocess to produce bacterial cellulose (BC) using waste streams from wine distilleries and the biodiesel industry: evaluation of BC for adsorption of phenolic compounds, dyes and metals

“…The HPLC system was equipped with a refractive index detector (RID-10A; Shimadzu Corp., Japan), column oven (CTO-10ASvp; Shimadzu Corp., Japan), and a ReproGel H column (250 × 8 mm, 9 μm; Dr. Maisch, Germany). The mobile phase was a 5 mM H 2 SO 4 aqueous solution with 0.6 mL/min flow rate at 40 °C oven temperature [ 23 ].…”

Growth Response of Non-Conventional Yeasts on Sugar-Rich Media: Part 2: Citric Acid Production and Circular-Oriented Valorization of Glucose-Enriched Olive Mill Wastewaters Using Novel Yarrowia lipolytica Strains

“…Being in line with the aforementioned, agri-food residues that are abundant, low- (or negative-) cost and sustainable should be valued as resources and re-introduced in value chains of the circular economy. This could be achieved via the implementation of microbial bioprocessing [ 3 , 4 ]. The fermentation media is critical for the efficient biosynthesis of microbial metabolites such as citric acid (CA) since it corresponds to more than 50% of the total production cost.…”