Production of Highly Porous Biochar Materials from Spent Mushroom Composts

The edible mushroom industry has grown significantly in recent years due to the dietary change and the demand for heathy food. However, the spent mushroom compost (SMC) will be produced in large quantities after the harvest, thus forming an agricultural waste requiring proper management other than dumping or burning. In this work, two types of SMCs with the cultivation of shiitake fungus (SF) and black fungus (BF) were converted into porous biochar products (a series of SMC-SF-BC and SMC-BF-BC) at higher pyrolysis temperatures (i.e., 400, 600 and 800 °C) based on their thermochemical characteristics, using thermogravimetric analysis (TGA). The pore and chemical properties of the resulting products, including surface area, pore volume, average pore size, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Fourier Transform infrared spectroscopy (FTIR), were studied to correlate them with the most important process parameter. The results showed that the pore properties of the biochar products indicated a significant increase with the increase in the pyrolysis temperature from 400 to 600 °C. The data on the maximal Brunauer-Emmett-Teller (BET) surface area for the biochar products produced at 800 °C (i.e., SMC-SF-BC-800 and SMC-BF-BC-800) were found to be 312.5 and 280.9 m2/g, respectively. Based on the EDS and FTIR, plenty of oxygen-containing functional groups were found on the surface of the resulting biochar products.

The Predation Behaviour of Fictor composticola on Parasitic Nematodes of Button Mushroom, Agaricus bisporus

In this study, the predation behaviour of male and female predatory nematode, Fictor composticola, was studied on five prey nematode species, Aphelenchus avenae, Aphelenchoides swarupi, Ditylenchus myceliophagus, Bursilla sp. and Panagrolaimus sp., found in the white button mushroom compost. The period of the study is of six months. The data recorded on number of encounters, part of the body of prey attacked, stage of the prey attacked, duration of feeding etc. The strike rate and prey susceptibility were calculated. The average number of encounters on all the five preys done by female F. composticola was 3.0 and that of the male was 6.0. Male F. composticola had more number of encounters on the prey nematode species than the females. Both the sexes preferred juvenile stages over adults as prey. The most attacked part by both females and males predator, was the posterior part of the prey body. In 80% of cases, female predators fed on the first encountered prey while males attacked the first encountered prey in 30% of cases only. The strike rate of female F. composticola was more (78.6%) than the male (48.2%). Mycophagous nematodes were more susceptible to predator’s attack than the microbivorous nematodes. The strike rate of the predator on different prey nematode species was found more on mycophagous nematodes than on microbivorous nematodes and minimum on Panagrolaimus sp. The average feeding duration of female F. composticola was 8 min and 31 sec and in the case of males it was 4 min and 11 sec.

Biosorption of Copper(II) and Iron(II) using Spent Mushroom Compost as Biosorbent

The application of the biosorption process and agricultural waste to treat heavy metals has drawn much attention. This method seems to be a more economical, environmentally friendly, and simple way for removing heavy metals from effluents. The study was conducted to explore the efficiency of the biosorption process utilizing spent mushroom compost to remove copper (II) and iron (II) from synthetic wastewater. Biosorption studies at different operating parameters, such as biosorbent dosage (1.0 – 5.0 g), pH (pH 4 – 8), contact time (1 - 30 minutes), and initial heavy metal concentration (10 - 100 mg/L), were conducted in batch experiments. The highest performance for copper (II) and iron (II) biosorption was found at 5.0 g biosorbent dosage of spent mushroom compost, unadjusted pH 6, 10 minutes of contact time, and 10 mg/L of initial concentration. The study was well fitted to the Langmuir isotherm model (R2 > 0.95) for copper (II) and iron (II) biosorption, which are much greater compared to the Freundlich model. The study is also very well suited to the pseudo-second-order (R2 > 0.999) than the pseudo-first-order kinetic models. In conclusion, the spent mushroom compost has the potential to be an effective biosorbent for removing copper (II) and iron (II) from synthetic wastewater.

Energy Potential of Oil Palm Empty Fruit Bunch (EFB) Fiber from Subsequent Cultivation of Volvariella volvacea (Bull.) Singer

EFB and EFB-based mushroom compost (SMC) from Volvariella volvacea cultivation is a promising energy feedstock because it has adequate nutrient quality. The biochemical methane potential (BMP) and calorific value (CV) of this biomass are investigated. Other analyses such as proximate, compositional, and final analysis; thermogravimetric analysis (TGA); and Fourier transform infrared spectroscopy (FTIR) are also performed. The biomass samples consist of two types of EFB, namely fibers (F) and pellets (P) and SMC from the subsequent cultivation of Volvariella volvacea, with samples FS and PS from the first cultivation and FS2 and PS2 from the second cultivation. P produces the highest biological efficiency (BE) of 28% compared to 9.83% for F. Subsequent cultivation with FS and PS then produces only 2.9 and 6.83% of BE. A higher amount of methane is measured in samples P and PS2, while better biodegradability is observed in PS2 and FS2, suggesting that subsequent cultivation is a good pretreatment of the substrate for anaerobic digestion (AD). CV is highest in F (20.57 MJ/kg), followed by P (19.06 MJ/kg), which is comparable to commercial wood pellet. Samples F, FS, and FS2 have higher ash content, which is due to higher mineral content. The cellulose composition is reduced to almost 50% during cultivation due to fungal metabolism, which is also evidenced by FTIR analysis. TGA analysis revealed that EFB-based SMC exhibits higher weight loss during combustion compared to EFB, which reduces its thermal properties. SMC of EFB is a high potential biomethane feedstock, but not recommended as a fuel pellet.

Application of Modified Spent Mushroom Compost Biochar (SMCB/Fe) for Nitrate Removal from Aqueous Solution

The public is already aware that nitrate pollution caused by nutrient runoff from farms is harmful to aquatic life and human health, and there is an urgent need for a product/technology to solve this problem. A biochar adsorbent was synthesized and used to remove nitrate ions from aqueous media based on spent mushroom compost (SMC), pre-treated with iron (III) chloride hexahydrate and pyrolyzed at 600 °C. The surface properties and morphology of SMCB/Fe were investigated using Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The effect of main parameters such as the adsorbent dosages, pH of the solutions, contact times, and ion concentrations on the efficiency of nitrate removal was investigated. The validity of the experimental method was examined by the isothermal adsorption and kinetic adsorption models. The nitrate sorption kinetics were found to follow the pseudo-second-order model, with a higher determination coefficient (0.99) than the pseudo-first-order (0.86). The results showed that the maximum percentage of nitrate adsorption was achieved at equilibrium pH 5–7, after 120 min of contact time, and with an adsorbent dose of 2 g L−1. The highest nitrate adsorption capacity of the modified adsorbent was 19.88 mg g−1.

Easy and effective analytical method of carbendazim, dimethomorph, and fenoxanil from Protaetia brevitarsis seulensis using LC-MS/MS

Traditionally in Korea, Protaetia brevitarsis seulensis (white-spotted flower chafer) has been used as a medicine, and recently has attracted increased attention due to its antithrombotic efficacy. Some of spent mushroom compost or fermented oak sawdust, a feedstock for P. brevitarsis, were contaminated with three fungicides, carbendazim, dimethomorph, and fenoxanil, which could be transferred to the insect. This study was aimed to optimize a simple extraction method combined with liquid chromatography tandem mass spectrometry and apply it to the real samples. After the pulverized samples (5 g) were extracted with acetonitrile (10 mL) and formic acid (100 μL), fat and lipids in the samples were slowly precipitated at -20°C for 24 hours. After eight different clean-up methods were investigated, the mixture of 150 mg MgSO4/25 mg PSA/25 mg C18 was selected due to optimal recovery of the target compounds. Recovery (77.9%‒80.8% for carbendazim, 111.2%‒116.7% for dimethomorph, and 111.9%‒112.5% for fenoxanil) was achieved with reasonable relative standard deviation (<5.5%) The analytical method developed in this study was used to analyze three compounds in the 24 insect samples donated by the insect farm owners but no target compounds were detected. These results can provide important data for establishing the pesticide safety standards for P. brevitarsis before the medical applications.

Effects of Repeated Application of Organic Soil Amendments on Horticultural Soil Physicochemical Properties, Nitrogen Budget and Yield

Application of organic amendments to soil is commonplace in domestic gardening. However, a vast array of materials could be labelled as ‘compost’ by retailers and suppliers. We investigated six different amendments currently used, or available for use, in horticulture: composted bark, composted bracken, spent mushroom compost, composted horse manure, garden waste compost (at two different application rates), and peat. Using a controlled field experiment, we examined the physicochemical differences between the amendments, the subsequent effects on soil characteristics, and resultant yield and biometrics of Lavatera trimiestris. Amended soils resulted in a significantly different multivariate soil environment and N budget when compared to the unamended control. However, the effect on yield and plant biometrics (number of flowers, plant height, etc.) depended on the amendment used. Application of garden compost resulted in up to a five-fold increase in yield. However, there was no significant difference in yields in soils amended with composted bark or peat, when compared to the unamended control. This has implications, as there is increasing pressure to remove peat from products available to domestic gardeners. The variability in the different amendments investigated in our research, in addition to the variable effects on plant growth parameters, suggests that repeated use of a single amendment may not be best practise for gardeners.

The Importance of Extraction Protocol on the Analysis of Novel Waste Sources of Lignocellulosic Biomass

As the utilization and consumption of lignocellulosic biomass increases, so too will the need for an adequate supply of feedstock. To meet these needs, novel waste feedstock materials will need to be utilized. Exploitation of these novel feedstocks will require information both on the effects of solvent extraction on the succeeding analysis of potential novel feedstocks and how accurate current methodologies are in determining the composition of novel lignocellulosic feedstocks, particularly the carbohydrate and lignin fractions. In this study, the effects of solvent extraction on novel feedstocks, including tree foliage, tree bark and spent mushroom compost, with 95% ethanol, water and both sequentially were examined. Chemical analyses were carried out to determine the moisture content, ash, extractives, post-hydrolysis sugars, Klason lignin (KL) and acid-soluble lignin (ASL) within the selected feedstocks. The result of extraction could be seen most strongly for Klason lignin, with a strong association between higher levels of Klason lignin levels and greater amounts of non-removed extractives (tree foliage and bark). Higher Klason lignin levels are reported to be due the condensation of non-removed extractives during hydrolysis, hence the lower Klason lignin determinations following extraction are more exact. In addition, total sugar determinations were lower following extractions. This is because of the solubility of non-cell-wall carbohydrates; thus, the determinations following extraction are more accurate representations of structural cell-wall polysaccharides such as cellulose. Such determinations will assist in determining the best way to utilize novel feedstocks such as those analyzed in this work.