Solid-State Fermentation of Steam-Exploded Opuntia ficus-indica Cladodes Using Trichoderma reesei CCT-2768 for the Production of Cellulolytic Enzymes.

The sustainable development of the drylands, i.e., regions with limited availability of water, depends on the exploitation of the few biomass types that can thrive in such conditions, such as the Opuntia ficus-indica, a plant of the Cactaceae family. In the present study, the cladodes of O. ficus-indica were used as a substrate by the fungus Trichoderma reesei CCT-2768 for the production of cellulolytic enzymes through solid-state fermentation. Firstly, the extraction of the mucilage, soluble components of industrial interest, was evaluated. Temperature, water-to-biomass ratio, and time of mixture were varied using an experimental design and impacted, especially, the pectin removal. Then, the lignocellulosic residue was used for the production of enzymes; the effect of the water activity, biomass pretreatment, mineral supplementation, temperature, and inoculum size on the enzymatic production were investigated using two sets of experimental designs. The steam explosion pretreatment exposed the fiber to the microbial action and boosted the enzyme production, provided that the medium was supplemented with salts. This combination has improved the production of xylanase, CMCase, FPase, and polygalacturonase by 27, 62, 98, and 185%, respectively. The temperature of 35 °C was determined as the optimal for the production of FPase, xylanase, and polygalacturonase, while no effect was observed on the production of CMCase and ß-glucosidase. The optimization of the enzymatic production performed in this study can potentially provide a new application for the Opuntia biomass and improve the sustainable development of the drylands.

Fungal protein.

This chapter reviews the uses of processed fungal cells as protein-rich foods in substitution to meat. Yeasts, mushrooms, and filamentous fungi have long been part of the human diet, improving the nutritional quality and taste of different foods. Recently, because of the populational growth and environmental impact caused by animal farming, the use of animal-derived protein has been raising concerns in public and scientific debates. Fungal biomass represents a nutritious, safe meat alternative that can help society in the reduction of greenhouse gases emissions and improve public health. Additionally, it provides all essential amino acids and has an interesting fatty acid profile. Current research is involved in finding new strains with improved efficiency, the investigation of new substrates (especially agro-industrial wastes) to reduce the environmental impact, and the development of new formulations to use mycoprotein in different dishes.

Mycoprotein: environmental impact and health aspects.

The term mycoprotein refers to the protein-rich food made of filamentous fungal biomass that can be consumed as an alternative to meat. In this paper, the impact caused by the substitution of animal-origin meat in the human diet for mycoprotein on the health and the environment is reviewed. Presently, mycoprotein can be found in the supermarkets of developed countries in several forms (e.g. sausages and patties). Expansion to other markets depends on the reduction of the costs. Although scarce, the results of life cycle analyses of mycoprotein agree that this meat substitute causes an environmental impact similar to chicken and pork. In this context, the use of inexpensive agro-industrial residues as substrate for mycoprotein production has been investigated. This strategy is believed to reduce the costs involved in the fungal cultivation and lower the environmental impact of both the mycoprotein and the food industry. Moreover, several positive effects in health have been associated with the substitution of meat for mycoprotein, including improvements in blood cholesterol concentration and glycemic response. Mycoprotein has found a place in the market, but questions regarding the consumer's experience on the sensory and health aspects are still being investigated.

Vegan-mycoprotein concentrate from pea-processing industry byproduct using edible filamentous fungi.

BACKGROUND: Currently around one billion people in the world do not have access to a diet which provides enough protein and energy. However, the production of one of the main sources of protein, animal meat, causes severe impacts on the environment. The present study investigates the production of a vegan-mycoprotein concentrate from pea-industry byproduct (PpB), using edible filamentous fungi, with potential application in human nutrition. Edible fungal strains of Ascomycota (Aspergillus oryzae, Fusarium venenatum, Monascus purpureus, Neurospora intermedia) and Zygomycota (Rhizopus oryzae) phyla were screened and selected for their protein production yield. RESULTS: A. oryzae had the best performance among the tested fungi, with a protein yield of 0.26 g per g of pea-processing byproduct from the bench scale airlift bioreactor cultivation. It is estimated that by integrating the novel fungal process at an existing pea-processing industry, about 680 kg of fungal biomass attributing to about 38% of extra protein could be produced for each 1 metric ton of pea-processing byproduct. This study is the first of its kind to demonstrate the potential of the pea-processing byproduct to be used by filamentous fungi to produce vegan-mycoprotein for human food applications. CONCLUSION: The pea-processing byproduct (PpB) was proved to be an efficient medium for the growth of filamentous fungi to produce a vegan-protein concentrate. Moreover, an industrial scenario for the production of vegan-mycoprotein concentrate for human nutrition is proposed as an integrated process to the existing PPI production facilities.