Solid-State Fermentation of Trichoderma spp.: A New Way to Valorize the Agricultural Digestate and Produce Value-Added Bioproducts

Abstract

In this study, the agricultural digestate from anaerobic biogas production mixed with food wastes was used as a substrate to grow Trichoderma reesei RUT-C30 and Trichoderma atroviride Ta13 in solid-state fermentation (SSF) and produce highvalue bioproducts, such as bioactive molecules to be used as ingredients for biostimulants. The Trichoderma spp. reached their maximum growth after 6 and 3 SSF days, respectively. Both Trichoderma species were able to produce cellulase, esterase, and citric and malic acids, while T. atroviride also produced gibberellins and oxylipins as shown by ultraperformance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) profiling. Experimental evaluation of germination parameters highlighted a significant promotion of tomato seed germination and root elongation induced by T. atroviride crude extracts from SSF. This study suggests an innovative sustainable use of the whole digestate mixed with agro-food waste as a valuable substrate in fungal biorefineries. Here, it has been applied to produce plant growth-promoting fungi and bioactive molecules for sustainable agriculture.

Optimization of Esterase Production in Solid-State Fermentation of Agricultural Digestate

“…An example of a successful biorefinery is the anaerobic conversion (AD) of biowaste into biogas and digestate. Digestate, the by-product of AD, is mainly and poorly valorized as biofertilizer and, recently, it has been investigated as a substrate in fungal biorefinery to produce organic acids, plant hormone-like molecules and enzymes [10]. This study investigates the potential application of T. asperellum R in a fungal biorefinery using digestate mixed with agro-industrial wastes as a substrate for enzyme production.…”

“…The ability of T. asperellum R to produce enzymes in SSF was verified using a previously set up protocol [10,14]. Briefly, the SSF substrate was composed of the whole digestate (70% w/w) mixed with apple, banana and grape (30% w/w).…”

“…The endoglucanase (EG) activity (EC 3.2.1.4) was assessed as reported by Bulgari and colleagues [10]. The release of reducing sugars was measured in a reaction mixture containing the crude extract and carboxymethyl cellulose (0.5% w/v) as a substrate in 50 mM Na acetate buffer (pH 5) at 50 • C for 60 min.…”

“…Cereal wastes and residues are the most investigated substrates for enzyme production in SSF, while the most common enzymes reported are xylanases, followed by cellulase, β-glucosidase, laccase and β-xylosidase [7]. Few studies have been carried out on esterase/lipase production in SSF; usually, different waste-based substrates such as digestate and wheat bran, with supplements, have been used with fungi belonging to the genera Trichoderma, Aspergillus, Cryphonectria and Rhizophus [8][9][10][11].…”

Solid-state fermentation converts rice bran into a high-protein feed ingredient for Penaeus monodon

“…The fungus Trichoderma is renowned for its ability to colonize diverse ecological niches, including soil, roots, and leaves, and is particularly noted for its secretion of substantial quantities of cellulases. This fungus has been documented to be a fast colonizer of cellulosic substrates and does not produce aflatoxins (Ahmed et al, 2009;Bulgari et al, 2023). Furthermore, it is known that this fungus can grow and utilize cellulosic rice stalks and rice milling byproducts as substrates and convert them into fungal biomass.…”