Assessment of coffee waste in formulation of substrate for oyster mushrooms Pleurotus pulmonarius and Pleurotus floridanus

Impact of bottom ash addition on Pleurotus ostreatus cultivation on coffee ground substrate

The study aimed to explore the potential use of coal-fired power plant bottom ashes in Pleurotus ostreatus cultivation using spent coffee grounds. The study analyzed five compositions of growth substrate for mushrooms: pure coffee grounds (I) as a control sample; coffee grounds substrate with the addition of 1% (II); 5% (III); 10% (IV) bottom ash; and bottom ash alone (V). The study revealed that compared to the control sample (I), the addition of 1% bottom ash (II) did not affect the time of mycelium growth but slowed fruiting body growth by 4 days. With 5% addition (III), mycelium growth slowed by 6 days, and fruiting body growth by 7 days. At 10% (IV), growth was completely inhibited. Compared to sample (I), fruiting bodies grown on sample (II) had higher phosphorus, copper, and zinc accumulation, while chromium, nickel, and lead levels were lower in fruiting bodies grown on samples (II) and (III). Additionally, fruiting bodies grown on samples (II) and (III) contained less iron, silicon, selenium, aluminum, calcium, and magnesium. The results presented in the article regarding the levels of contamination in the cultivated mushrooms and in the substrate after cultivation, indicate the potential for their further management.

Growth and Yield Performance of Pleurotus ostreatus Cultivated on Agricultural Residues

Food insecurity and malnutrition are among the major problems in most developing nations recently. Mushroom cultivation is one of the promising strategies to overcome these challenges. The growth and productivity of mushrooms differ because of their wide range of cultivation substrates. Cultivating Pleurotus ostreatus on suitable substrates is one of the key factors affecting its growth and productivity. This study was, therefore, conducted to investigate the effect of cultivation substrates, namely straws of tef (Trt1), barley (Trt2), and wheat (Trt3), husks of faba bean (Trt4) and field pea (Trt5), and sawdust (Trt6) alone, and their mixture (1:1, w/w) (Trt7) on the growth and yield of P. ostreatus. Mycelial colonization, primordial formation, and days to first harvest were faster (13.00, 19.67, and 22.67 days) for the P. ostreatus cultivated on Trt7 whereas those grown on Trt6 were delayed (18.00, 27.00, and 29.67 days), respectively. Trt7 gave a higher (67.33) fruiting body/bunch and total yield (2001.70 g/bag). Biological efficiency was also significantly (p < 0.05) higher for Trt7 (238.64%). Strong relationships between cap diameter and mushroom yield (r = 0.84***), number of bunches (r = 0.76***), number of fruiting bodies (r = 0.80***), stipe length (r = 0.83***), and total yield (r = 0.84***) were among significant positive correlations observed. In conclusion, cultivating P. ostreatus on the Trt7 (mixed substrate) is recommended rather than using either of the residues alone.

Efficient conversion of tea residue nutrients: Screening and proliferation of edible fungi

Despite lignocellulose hindering the extraction of intracellular components, tea residue can serve as an excellent substrate for fungal fermentation owing to their lignocellulose-degrading abilities. Thus, the fermentation efficiencies of Lentinus edodes, Lentinus sajor-caju (Fr.), Flammulina filiformis, Hericium erinaceus, Pleurotus pulmonarius, and Monascus kaoliang B6 were evaluated using tea residue as a medium. P. pulmonarius and L. sajor-caju (Fr.) exhibited the fastest growth rates, with colony radii of 33.1 and 28.5 mm, respectively. M. kaoliang B6 demonstrated substantial degradation abilities for cellulose, hemicellulose, and lignin, with decolorization radii of 12.2, 0.9, and 8.5 mm, respectively. After a 9-days liquid fermentation, M. kaoliang B6 achieved the highest conversion efficiency at 27.8%, attributed to its high cellulase (191 U∙mL-1) and lignin peroxidase (36.9 U∙L-1) activities. P. pulmonarius and L. sajor-caju (Fr.) showed lower conversion rates of 8.6% and 3.8%, despite having high hemicellulase activities (67.1 and 70.9 U∙mL-1). Fermentation by M. kaoliang B6 resulted in a reduction of protein and total sugar content in the tea residue by 174 and 192 mg g-1, by which the mycelium's protein and total sugar content increased by 73 and 188 mg g-1. Co-fermentation of these three strains had little effect on the improvement of conversion efficiency, which might owe to the antagonistic interactions among the strains. Generally, utilizing tea residue for edible fungi fermentation is a sustainable process for bio-waste treatment, enabling efficient nutrient conversion under mild conditions without adding chemicals.

Fabrication of mycelium (oyster mushroom)-based composites derived from spent coffee grounds with pineapple fibre reinforcement

Mycelium-based composites (MBCs) are eco-friendly materials made by combining mushroom mycelia with lignocellulosic biomass, offering diverse applications such as packaging and construction. The specific characteristics of MBCs can be significantly influenced by the choice of substrates and reinforcing materials during myco-fabrication. This study aims to improve MBCs sourced from Pleurotus ostreatus (oyster mushroom) using spent coffee grounds (SCGs) as the main substrate, combined with natural pineapple fibres (NPFs). NPFs are incorporated to SCGs in different proportions (10% to 30%) to explore their potential in improving the material properties of MBCs. The findings demonstrate that the mechanical properties of MBCs, as well as the physical and chemical properties, can be altered by manipulating the proportion of NPFs. The MBCs reinforced with 10% NPFs exhibit the highest density and compressive strength, while the MBC with 30% NPFs outperforms others in terms of bending strength, water absorption, swelling, and sound absorption. Furthermore, a fire resistance test affirms the non-combustible properties of the MBC made of SCGs and NPFs, thereby demonstrating its safety features. These MBCs, made from oyster mushroom, embody a hopeful substitute for product creation and production in relation to practical usage, eco-friendly manufacturing techniques, and recyclability throughout its lifecycle.

Use of oyster mushrooms (Pleurotus ostreatus) for increased circularity and valorization of rapeseed residues

In Europe, rapeseed is a common oilseed crop, resulting in the production of 20 million tons of rapeseed press cake yearly. This press cake can be further upcycled and a protein fraction can be extracted for food purposes, leaving de-proteinized fiber-rich residues. This study examined the use of these residues in the production of oyster mushrooms (Pleurotus ostreatus) and of the spent substrate as feed, since mushroom cultivation may improve the feed properties of substrate. In terms of mushroom production, the addition of rapeseed press residues was beneficial, giving significantly higher biological efficiency (BE = 93.1 ± 11.0%) compared with the control, sugar beet pulp substrate (70.0 ± 6.6%). This increase in productivity can most likely be explained by higher energy content in the substrate supplemented with lipid-rich rapeseed residues. Despite differences in BE between the substrates, high similarity was observed in lipid composition of the fruiting bodies (lipid profile dominated by linoleic acid (18:2), palmitic acid (16:0), and oleic acid (18:1)), and in protein and moisture content. After mushroom harvest, approximately 70% of the initial dry weight of both substrates remained as a possible feed source. Both substrates had significantly lower levels of carbohydrates and unchanged neutral detergent fiber content after mushroom harvest, and both gave lower in vitro digestibility, total gas production, and methane production. However, protein concentration differed between the substrates, with the highest concentration (15.8% of dry weight) found in spent substrate containing rapeseed press residues. The result of the present study suggests that the de-proteinized rapeseed press residue is a resource well-suited for use in the production of mushrooms and feed.

The anti-allergic potential of stingless bee honey from different botanical sources via modulation of mast cell degranulation

BACKGROUND

Allergy is an inflammatory disorder affecting around 20% of the global population. The adverse effects of current conventional treatments give rise to the increased popularity of using natural food products as complementary and alternative medicine against allergic diseases. Stingless bee honey, commonly known as Kelulut honey (KH) in Malaysia, has been used locally as a traditional remedy to relieve cough and asthma. This study evaluated the anti-allergic potential of KH collected from four different botanical sources on phorbol ester 12-myristate-3-acetate and calcium ionophore-activated human mast cells.

METHODS

The present study examined the inhibitory effects of all collected honey on the release of selected inflammatory mediators, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-4, IL-6, IL-8, histamine, and β-hexosaminidase in an activated HMC. Besides that, all honey's total phenolic content (TPC) was also examined, followed by using liquid chromatography with tandem mass spectrometry (LC-MS/MS) to identify the phytochemicals in the honey. Further examination of the identified phytochemicals on their potential interaction with selected signaling molecules in an activated mast cell was conducted using computational methods.

RESULTS

The results indicated that there were significant inhibitory effects on all selected inflammatory mediators' release by KH sourced from bamboo (BH) and rubber tree (RH) at 0.5% and 1%, but not KH sourced from mango (AH) and noni (EH). BH and RH were found to have higher TPC values and were rich in their phytochemical profiles based on the LC-MS/MS results. Computational studies were employed to determine the possible molecular target of KH through molecular docking using HADDOCK and PRODIGY web servers.

CONCLUSIONS

In short, the results indicated that KH possesses anti-allergic effects towards an activated HMC, possibly by targeting downstream MAPKs. However, their anti-allergic effects may vary according to their botanical sources. Nevertheless, the present study has provided insight into the potential application of stingless bee honey as a complementary and alternative medicine to treat various allergic diseases.

Production of oyster mushroom (Pleurotus ostreatus) from some waste lignocellulosic materials and FTIR characterization of structural changes

In this study, oyster (Pleurotus ostreatus) mushroom was cultivated from hazelnut branches (HB) (Corylus avellana L.), hazelnut husk (HH), wheat straw (WS), rice husk (RH) and spent coffee grounds (CG). Hazelnut branch waste was used for the first time in oyster mushroom cultivation. In the study, mushrooms were grown by preparing composts from 100 to 50% mixtures of each waste type. Yield, biological activity, spawn run time, total harvesting time and mushroom quality characteristics were determined from harvested mushroom caps. In addition, chemical analysis of lignocellulosic materials (extractive contents, holocellulose, α-cellulose, lignin and ash contents) were carried out as a result of mushroom production and their changes according to their initial amounts were examined. In addition, the changes in the structure of waste lignocellulosic materials were characterized by FTIR analysis. As a result of the study, 172 g/kg yield was found in wheat straw used as a control sample, while it was found as 255 g/kg in hazelnut branch pruning waste. The highest spawn run time (45 days) was determined in the compost prepared from the mixture of hazelnut husk and spent coffee ground wastes. This study showed that HB wastes can be used for the cultivation of oyster mushroom (P. ostreatus). After mushroom cultivation processes, holocelulose and α-cellulose content rates decreased while ash contents increased. FTIR spectroscopy indicated that significant changes occurred in the wavelengths regarding cellulose, hemicellulose and lignin components. Most significant changes occurred in 1735, 1625, 1510, 1322 and 1230 wavelengths.

Biochar produced by combining lignocellulosic feedstock and mushroom reduces its heterogeneity

To reduce the feedstock-sourced heterogeneity of biochar, mushrooms, cultivated from lignocellulosic feedstocks (LFs), were used as precursors for biochar preparation. The coefficient of variation (CV) was adopted to show the homogeneity changes. In contrast to LFs, mushrooms produced relatively lower CVs in terms of elemental and proximate analysis. Furthermore, the CV of H/C (9.20%) and O/C (13.32%) of mushroom-based biochars (MRBCs) was lower than that of LF-based biochars (LFBCs), suggesting more homogeneous aromaticity and hydrophilicity. The relatively lower CV of the volatile matter (0.87%), fixed carbon (0.45%), and ash (2.44%) of MRBCs suggested an improvement in the homogeneity of chemical components. The homogenized physical structure was reflected in the lack of a difference in pore characteristics of MRBCs. The lower CVs (1.89-14.82%) for the pollutant adsorption of MRBCs, implied more stable performance. In conclusion, converting LFs to mushrooms reduced the precursor's heterogeneity, consequently homogenizing the biochar's properties and performance.