ABSTRACT
Lentinus edodes (shiitake) is a basidiomycete that has been consumed for more than 2000 years because of its nutritional value and health benefits. It has a low lipid content, high fiber content, and a considerable amount of proteins; it also contains B vitamins and minerals in addition to a wide range of functional metabolites including polysaccharides, polysaccharopeptides, lectins, and secondary metabolites with bioactivity, e.g., lentinan, a ß-(1-3)-glucan with immunomodulatory activity, among others. Extracts and pure compounds of shiitake exhibit antibacterial, antifungal, cytostatic, antioxidant, anticancer, and immunomodulatory activity. Because of these attributes, different products derived from shiitake are on the market and are sold as dietary supplements. The traditional substrate for shiitake production is oak wood, yet the search for unconventional substrates has intensified over the past three decades. In particular, submerged cultivation of medicinal mushrooms has attracted great interest because it enables greater control of different fermentation factors to obtain products of interest. However, it is necessary to perform in vivo studies to determine the appropriate doses, side effects, and action spectrum of different bioactive compounds and fractions as well as to improve their production in liquid media and to potentiate their activity. We present an updated review of existing studies on the production of biomass and bioactive compounds of L. edodes in liquid culture and on solid fermentation for obtaining secondary mycelia and basidiomata.
Subject(s)
Biomass , Dietary Supplements , Nutritive Value , Shiitake Mushrooms/chemistry , Fermentation , Mycelium/chemistry , Shiitake Mushrooms/growth & development , Wood/microbiologyABSTRACT
Grapes are widely produced in northwestern Mexico, generating many wood trimmings (vineyard prunings) that have no further local use. This makes vineyard prunings a very attractive alternative for the cultivation of white-rot medicinal mushrooms such as Lentinus edodes. This type of wood can also offer a model for the evaluation of oxidative enzyme production during the fermentation process. We tested the effect of wood from vineyard prunings on the vegetative growth of and production of ligninolytic enzymes in L. edodes in solid-state fermentation and with wheat straw as the control substrate. The specific growth rate of the fungus was 2-fold higher on vineyard pruning culture (µM = 0.95 day-1) than on wheat straw culture (µM = 0.47 day-1). Laccase-specific production was 4 times higher in the vineyard prunings culture than on wheat straw (0.34 and 0.08 mU · mg protein-1 · ppm CO2-1, respectively), and manganese peroxidase production was 3.7 times higher on wheat straw culture than on vineyard prunings (2.21 and 0.60 mU · mg protein-1 · ppm CO2-1, respectively). To explain accurately these differences in growth and ligninolytic enzyme activity, methanol extracts were obtained from each substrate and characterized. Resveratrol and catechins were the main compounds identified in vineyard prunings, whereas epigallocatechin was the only one detected in wheat straw. Compounds susceptible to enzymatic oxidation are more bioavailable in vineyard prunings than in wheat straw, and thus the highest L. edodes growth rate is associated with the presence of these compounds.