Evaluation of the Extraction of Bioactive Compounds and the Saccharification of Cellulose as a Route for the Valorization of Spent Mushroom Substrate

Abstract

The extraction of bioactive compounds and cellulose saccharification are potential directions for the valorization of spent mushroom substrate (SMS). Therefore, investigating the suitability of different extraction methods for recovering bioactive compounds from SMS and how the extraction affects the enzymatic saccharification is of uppermost relevance. In this work, bioactive compounds were extracted from Pleurotus spp. SMS using four extraction methods. For Soxhlet extraction (SoE), a 40:60 ethanol/water mixture gave the highest extraction efficiency (EE) (69.9–71.1%) among the seven solvent systems assayed. Reflux extraction with 40:60 ethanol/water increased the extraction yield and EE compared to SoE. A shorter reflux time yielded a higher extraction of carbohydrates than SoE, while a longer time was more effective for extracting phenolics. The extracts from 240 min of reflux had comparable antioxidant activity (0.3–0.5 mM GAE) with that achieved for SoE. Ultrasound-assisted extraction (UAE) at 65 °C for 60 min allowed an EE (~82%) higher than that achieved by either reflux for up to 150 min or SoE. Subcritical water extraction (SWE) at 150 °C resulted in the best extraction parameters among all the tested methods. Vanillic acid and chlorogenic acid were the primary phenolic acids identified in the extracts. A good correlation between the concentration of caffeic acid and the antioxidant activity of the extracts was found. Saccharification tests revealed an enhancement of the enzymatic digestibility of SMS cellulose after the extraction of bioactive compounds. The findings of this initial study provide indications on new research directions for maximizing the recovery of bioactive compounds and fermentable sugars from SMS.

Low dietary oyster mushroom spent substrate limitedly ameliorates detrimental effects of feeding combined marula seed cake and mucuna seed meal as soya bean replacements in broiler chickens

“…The observed lack of effect of dietary OMSS on all haematological parameters suggests the safety of the spent substrate as a broiler chicken feed additive and corroborates previous studies with the modern birds and geese (Ullah et al 2020 ; Klausen et al 2023 ). Indeed, the OMSS is a sterile by-product from the cultivation of oyster mushrooms, a safe human food that is not only rich in nutrients but also a plethora of low-molecular weight bioactive compounds and antioxidant enzymes (Corrêa et al 2016 ; Rizzo et al 2021 ) that are secreted and deposited onto the spent substrate (Klausen et al 2023 ). Further demonstrating its safety for broiler chickens, dietary OMSS intake augmented the MSC and MSM-induced decrease in serum SDMA and alanine transaminase as it abrogated the increase in serum alkaline phosphatase.…”

Pleurotus ostreatus Mushroom: A Promising Feed Supplement in Poultry Farming

“…Moreover, despite having a 45% water content, SMS possesses a compact composition with a comparatively lower bulk density than manure [56]. Furthermore, extractive compounds presented in SMS are derived from fungal biomass (fungal mycelium), encompassing carbohydrates like β-glucans, as well as proteins and sterols [57], chitin-glucan complex, phenolics, and flavonoids [58], which can be extracted with conventional and modern techniques [57] and then used for their antimicrobial and prebiotic benefits in the food, pharmaceutical, and poultry industries [59]. Generally, there are some groups of bioactives that can be found in P. ostreatus, including polysaccharides, lovastatin, ergosterols and phytochemicals (Figure 1).…”

Special Issue “Lignocellulosic Biomass II”

“…Gallic acid, vanillic acid, vanillin, and apigenin were the major phenolics found in the extracts. Klausen et al [10] evaluated the extraction of bioactive compounds and cellulose saccharification as valorization strategies for spent mushroom substrate (SMS). Four extraction methods, namely Soxhlet, reflux, SWE, and ultrasound-assisted extraction, were used.…”