Spent Mushroom Substrate Research Articles

Bio-preparation of CuO@ZnO nanocomposite via spent mushroom substrate and its application against Candida albicans with molecular docking study

Bio-preparation of CuO@ZnO nanocomposite via spent mushroom substrate and its application against Candida albicans with molecular docking study

Spent Mushroom Substrate Improves Microbial Quantities and Enzymatic Activity in Soils of Different Farming Systems.

Organic fertilizers, such as spent mushroom substrate (SMS), improve soil fertility, but studies comparing their effects on different agricultural soils are limited. In this study, the effects of standard, SMS and composed fertilizers on soils from conventional-integrated, organic and biodynamic farming were investigated. Soil samples were analyzed for microorganisms and the activity of β-glucosidase (β-GLU), β-1,4-N-acetylglucosaminidase (NAG), urease (URE), arylamidase (ARN), phosphatase (PHOS), acid phosphatase (PAC), alkaline phosphatase (PAH) and arylsulphatase (ARS). Biodynamic soil showed the highest microbial counts and enzyme activities, followed by organic and conventional soils. SMS significantly increased the number of microorganisms and enzyme activities, especially in biodynamic and organic soils. Seasonal variations affected all microorganisms and most enzymes in all soils, except NAG in conventional and organic soils. Biodynamic soil showed stable activity of enzymes and microorganisms throughout the year, indicating greater stability. This study concludes that soil microorganisms and enzyme activities respond differently to fertilization depending on the soil type, with SMS demonstrating beneficial effects in all tested soils.

Effects of aging processes on spent mushroom Substrate-Derived Biochar: Adsorption characteristics of Cd(II) and Cr(VI)

To explore how chemical, physical and biological process impact the adsorption capacity of biochar for cations and anions, five kinds of spent mushroom substrate biochars including PB (carbonized Auricularia auricula substrate at 600 °C for 6 h), NB (Aged PB at 25 °C and 40 % moisture for 12 mon), AB (PB treated with 20 % mixed acid solution at 70 °C for 6 h), FB (PB subjected to 16 freeze–thaw cycles between − 20 °C and 25 °C) and MB (PB incubated with microbes from contaminated soil for 15 cycles) were prepared under simulated conditions, the internal mechanisms were revealed. Results showed that all aging processes caused a variation in crystal quantity and structure on different biochar. AB, NB and MB had higher hydrophilicity and polarity, and more positive charges than PB. Moreover, AB and MB had a higher cation exchange capacity (CEC) (70.7 and 75.3 cmol/kg) and more oxygen-containing functional groups than PB. MB has the maximum adsorption capacity for Cd(II) (24.2 mg/g), followed by PB (23.5 mg/g), FB (22.7 mg/g), NB (22.2 mg/g), and AB (22.0 mg/g). Langmuir model better described the Cd(II) adsorption onto NB, FB, and PB, while Freundlich better described AB and MB. As for Cr(VI), the maximum adsorption capacity followed the order: MB (24.1 mg/g) > AB (23.7 mg/g) > FB (23.5 mg/g) > PB (23.0 mg/g) > NB (22.7 mg/g). Langmuir model was better for Cr(VI) adsorption onto FB and PB, while Freundlich was better for AB, NB and MB. The pseudo-first-order kinetic model fits for Cd adsorption by FB，while the pseudo-second-order kinetic model fit for the adsorption of Cd and Cr by other biochars. The adsorption of Cr by all biochars was significantly related to the content of lactone group. Acidification and organic acids from microorganisms increased the pHPZC values of AB and MB, which was not conducive to the adsorption of Cd. The surface fragmentation of FB caused by the freezing and thawing process promoted its adsorption of Cd.

Plant-Derived Waste as a Component of Growing Media: Manifestations, Assessments, and Sources of Their Phytotoxicity.

Every year, approximately 2 billion tons of plant-derived waste (such as straw and crop residues) are generated globally, most of which are either incinerated, dumped, or landfilled without proper planning, leading to severe environmental pollution and resource wastage. Plant-derived waste exhibits potential advantages as a growing media component in various aspects. However, numerous studies have also indicated that plant-derived waste generally possesses strong phytotoxicity, which must be removed or reduced before being utilized as a growing media component. Therefore, accurately assessing their phytotoxicity and appropriately modifying it to ensure their support for plant growth when used as a growing media component is crucial. This paper reviews the manifestation and assessment methods of phytotoxicity in plant-derived waste; systematically summarizes the phytotoxicity sources of three common types of plant-derived waste (garden waste, crop straw, and spent mushroom substrate), as well as the toxic mechanisms of two representative phytotoxic substances (phenolic compounds and organic acids); and proposes some insights into further research directions. By consolidating insights from these studies, this review aims to deepen our understanding of phytotoxicity and its implications, and offer valuable references and guidance for future research endeavors and practical applications.

Valorization of Spent Mushroom Substrate (SMS) as a sustainable approach to remediation of xenobiotic compounds in groundwater - A comprehensive review

In the present era of the industrial revolution, chemical-based agriculture practices, and urbanization, the environment has severe repercussions from various xenobiotics and has become a pitfall worldwide. Xenobiotic compounds such as heavy metals, dyes, polycyclic aromatic hydrocarbons (PAHs), oil spills, pharmaceuticals' active compounds (PhACs), and agrochemicals show detrimental effects on the environment through long-term persistence causing biomagnification, pollution, etc. In the last few decades, researchers have dedicated themselves to developing different physical and chemical remediation methods, although facing several drawbacks and challenges and searching for eco-friendly alternatives like bioremediation. Conventionally bioremediation utilizes biological agents such as plants, microbes, fungi, etc. To reduce environmental pollutants' effects. Although conventional bioremediation has certain limitations, SMS (spent mushroom substrate) has recently drawn great attention worldwide because of its low cost, environment-friendly nature, easy availability, and higher remediation efficiency. Scientists have used waste mushroom SMS for bioremediation purposes for various xenobiotic compounds. Therefore, the present review's foremost aim is to encompass the role of mushroom SMS in the remediation of xenobiotic compounds, techniques for studying the adsorbent properties of SMS, factors affecting the adsorption process, and the probable mechanism involved in its remediation process. This study has noteworthy findings implying that eco-friendly multi-purpose SMS has great efficacy against environmental contaminants, and its removal efficiency gets increased with combinatorial approaches like SMS amendments (biochar, etc), phytoremediation, rhizoremediation, and nanoremediation. Various mechanisms, including ion exchange, free radical reactions, enzymatic processes, microbe-mediated remediation, permeation, and chelation, may play a role in SMS-mediated groundwater and environmental contaminant remediation.

A New Recycling Method through Mushroom Cultivation Using Food Waste: Optimization of Mushroom Bed Medium Using Food Waste and Agricultural Use of Spent Mushroom Substrates

Food waste is generated in large amounts locally and globally, and requires expenditure for disposal. However, it has high nutritional value and almost no toxic components. Therefore, it can be returned to mushroom mediums for further use, leading to food waste circulation. Though disposing of spent mushroom substrate (SMS) after harvesting is an additional problem, there have been increased efforts to compost it and apply it to the soil for growing vegetables. This study, therefore, aimed to optimize (1) mushroom spawn production with rice hull, (2) mushroom substrates using food waste to accelerate food waste recycling, and (3) the utilization of SMS as an organic fertilizer. An optimal substrate composition and high yield were obtained at 120–140 g of food waste per bag among substrates from Pleorutus ostreatus and Pleorutus citrinopileatus; therefore, using a high ratio of food waste in the mushroom mediums was achieved. On the other hand, the SMS of P. citrinopileatus demonstrated higher plant biomass growth, at 36 g, than that of P. ostreatus, at 21.2 g, in a treatment using SMS + okara. The present discovery is that people may be encouraged to be mindful of food loss by the delivery of mushrooms and plants grown from agro/food waste to the dining table, and this circular system may therefore be used as a key resource in mushroom and plant cultivation and to achieve a zero-emission cycle.

Evaluation of chemical properties and humification process during co-composting of spent mushroom substrate (Pleurotus ostreatus) and pig manure under different mass ratios

Spent mushroom substrate (SMS) from Pleurotus ostreatus is high in salinity, susceptible to deterioration caused by mold, and not suitable for direct application in soil. Its high C/N ratio and low pH inhibit the humification process during composting. Pig manure (PM) possesses high density and low porosity, impeding microbial metabolism. Co-composting SMS and PM can overcome these challenges. A 120-day composting experiment was conducted with varying mass ratios of SMS and PM, supplemented with calcium bentonite and microbial inoculum. After composting, there was observed a significant rise in the N and K2O contents, ranging from 11.1% to 84.1% and 55.1%–296.8%, respectively. Additionally, there was a decrease in the C/N ratio by a range of 18.9%–60.1%. The total nutrient content of SMS post-composting solely was a mere 4.9%, failing to meet the 5% required by China's Professional Standard outlined for organic fertilizers (NY/T525-2021). Composting PM alone simplified the molecular structure of humic-extracted acid (HE) and reduced the C content of humic acid (HA) by up to 18.1%. In contrast, co-composting SMS and PM in equal proportions stimulated microbial consumption of water-soluble substances, resulting in increase in C contents of HE and HA by 11.5% and 18.7%, respectively, along with a 15.4% rise in the polymerization level of the composted materials. Furthermore, this combination facilitated the conversion of inert humic component, reducing C content of humin by 79.3%, lowering the electrical conductivity (EC) value by 23.0%, and boosting GI value by 154.1%. Increasing the proportion of SMS in co-compost proved advantageous in enriching its organic matter content. The composting process involved bio-degradation of O-containing functional groups like phenols and alcohols, utilization of polysaccharides by microorganisms, and development of carboxyl groups in the HA. Based on the above index analysis, the most effective compost ratio to achieve higher humification level and compost quality was determined to be a mass ratio of SMS to PM of 5:5, followed by 6:4.

Enhanced removal of antibiotics and heavy metals in aquatic systems using spent mushroom substrate-derived biochar integrated with Herbaspirillum huttiense.

A novel integrated removal strategy was developed to enhance the concurrent elimination of copper (Cu), zinc (Zn), oxytetracycline (OTC), and enrofloxacin (ENR) from the aqueous environments. The underlying adsorption mechanisms of spent mushroom substrate (SMSB) and the Herbaspirillum huttiense strain (HHS1), and their efficacy in removing Cu, Zn, OTC, and ENR was also examined. Results showed that the SMSB-HHS1 composite stabilized 29.86% of Cu and 49.75% of Zn and achieved removal rates of 97.95% for OTC and 59.35% for ENR through a combination of chemisorption and biodegradation. Zinc did not affect Cu adsorption, and ENR did not impact the adsorption of OTC on SMSB. However, the co-presence of OTC and ENR modified the adsorption behaviors of both Cu and Zn. Copper and Zn enhanced the adsorption of OTC and ENR by serving as bridging agents, facilitating the interaction between the contaminants and SMSB. Conversely, OTC and ENR inhibited the adsorption process of Cu by obstructing its interaction with the SMSB and occupying the oxygen-containing functional groups. The ‒OH (3415 cm-1) and C-O-C (1059 cm-1) functional groups were identified as the principal active sites to form hydrogen bonds and interact with Cu and Zn, leading to the formation of CuP4O11 and Zn4CO3(OH)6H2O. HHS1 also enhanced antibiotic removal through biodegradation, as evidenced by the decrease of ‒C‒O and increase of ‒C = O groups. This study underscores the innovative potential of the SMSB-HHS1 composite, offering a sustainable approach to addressing multifaceted pollution challenges in the aquatic environments.

Hydroalcoholic Extracts from Pleurotus ostreatus Spent Substrate with Nematocidal Activity against Nacobbus aberrans Phytonematode and the Non-Target Species Panagrellus redivivus.

Pleurotus ostreatus, an edible mushroom widely consumed worldwide, generates a by-product known as spent mushroom substrate (SMS). This material has demonstrated biological activity against agricultural crop pathogens. In this study, we evaluated the nematocidal effectiveness of hydroalcoholic extracts (T5, T2, AT5, and AT2) derived from SMS of P. ostreatus against (J2) of the phytonematode Nacobbus aberrans and assessed their potential toxicity towards the non-target nematode Panagrellus redivivus. Among these extracts, AT5 exhibited the highest efficacy against N. aberrans and was the least toxic against P. redivivus. Liquid-liquid partitioning yielded the AQU fraction, which showed significant nematocidal activity against J2 (75.69% ± 8.99 mortality), comparable to chitosan. The GC-MS analysis revealed the presence of several compounds, including palmitic acid, linoleic acid, and 2,4-Di-tert-butylphenol. These findings are consistent with studies confirming the antagonistic effectiveness of these compounds against phytonematodes. Additionally, all extracts exhibited toxicity against P. redivivus, with T2 being the most toxic. Our findings demonstrate that while the AT5 extract displays antagonistic effectiveness against both N. aberrans and P. redivivus, it was the least toxic among the extracts tested. Thus, SMS of P. ostreatus holds potential as a source of nematocidal compounds, which could offer significant benefits for agricultural pest control.

Dietary incorporation of brown seaweed spent oyster mushroom substrate alters growth performance, physiological responses and meat quality parameters in Boschveld roosters

Use of brown seaweed (Ecklonia maxima) as a nutraceutical source in indigenous chicken diets is limited by high dietary fibre levels. Inoculating seaweeds with oyster mushroom (Pleurotus ostreatus) spawn (OMS) could enhance the utility of the spent mushroom substrate (SMS). This study investigated the effect of feeding incremental levels of brown seaweed SMS on growth performance, physiological responses, and meat quality parameters in Boschveld roosters. A total of 324, 4-week-old Boschveld roosters were weighed and randomly allotted to 36 pens (9 birds per pen) to produce six replicates per dietary treatment. The diets were formulated as follows: a standard grower diet (CON); and CON containing 150 g/kg of brown seaweed inoculated with OMS at 0 (SMS0), 20 (SMS20), 30 (SMS30), 40 (SMS40) and 50% (SMS50). Birds fed diet CON had the least feed intake (p < 0.05) than all the other SMS treatment levels in weeks 7, 8, 12, 14 and 15. Diet SMS40 promoted higher (p < 0.05) body weight gain (BWG) than CON in weeks 6, 7, 9 and 14. Gain-to-feed ratio linearly increased in weeks 7 [R2 = 0.288; p = 0.010], 11 [R2 = 0.581, p = 0.0001] and 14 [R2 = 0.389, p = 0.004], respectively. Quadratic responses (p < 0.05) were observed for BWG in week 5, white blood cells, heterophils, platelets, lymphocytes, monocytes, and relative spleen and large intestine weights as OMS levels increased. Linear increases were recorded for slaughter [R2 = 0.197, p = 0.017] and breast weights [R2 = 0.197, p = 0.020] as OMS levels increased. Diet SMS0 promoted higher (p < 0.05) relative caeca weights than the CON and SMS treatment groups. Neither quadratic nor linear responses (p > 0.05) were observed for breast meat quality parameters. In conclusion, feeding brown seaweed SMS improved growth performance and slaughter weight, altered some blood parameters and internal organs, without affecting breast meat quality of Boschveld roosters. Based on the quadratic response for BWG, the optimum OMS level was deduced at 20% in a brown seaweed-based Boschveld rooster diet.

One stone two birds: Recycling of an agri-waste to synthesize laccase-immobilized hierarchically porous magnetic biochar for efficient degradation of aflatoxin B1 in aqueous solutions and corn oil

Aflatoxin B1 (AFB1) contamination of oils is a serious concern for the safety of edible oil consumers. Enzyme-assisted detoxification of AFB1 is an efficient and safe method for decontaminating oils, but pristine enzymes are unstable in oils and require modifications before use. Therefore, we designed a novel and magnetically separable laccase-carrying biocatalyst containing spent-mushroom-substrate (SMS)-derived biochar (BF). Laccase was immobilized on NH2-activated magnetic biochar (BF-NH2) through covalent crosslinking, which provided physicochemical stability to the immobilized enzyme. After 30 days of storage at 4 °C, the immobilized laccase (product named “BF-NH2-Lac”) retained ~95 % of its initial activity, while after five repeated cycles of ABTS oxidation, ~85 % activity retention was observed. BF-NH2-Lac was investigated for the oxidative degradation of AFB1, which exhibited superior performance compared to free laccase. Among many tested natural compounds as mediators, p-coumaric acid proved the most efficient in activating laccase for AFB1 degradation. BF-NH2-Lac demonstrated >90 % removal of AFB1 within 5.0 h, while the observed degradation efficiency in corn oil and buffer was comparable. An insight into the adsorptive and degradative removal of AFB1 revealed that AFB1 removal was governed mainly by degradation. The coexistence of multi-mycotoxins did not significantly affect the AFB1 degradation capability of BF-NH2-Lac. Investigation of the degradation products revealed the transformation of AFB1 into non-toxic AFQ1, while corn oil quality remained unaffected after BF-NH2-Lac treatment. Hence, this study holds practical importance for the research, knowledge-base and industrial application of newly proposed immobilized enzyme products.

Enhancing biodegradation of vegetable oil-contaminated soil with soybean texturized waste, spent mushroom substrate, and stabilized poultry litter in microcosm systems.

Industrial activities contribute to environmental pollution, particularly through unregulated effluent discharges, causing adverse effects on ecosystems. Vegetable oils, as insoluble substances, exacerbate this pollution, forming impermeable films and affecting the oxygen transfer, leading to serious habitat disruption. Organic wastes, such as soybean texturized waste, spent mushroom substrate, and stabilized poultry litter, were assessed for their efficacy in enhancing the degradation of vegetable oil in contaminated soil. For this purpose, contaminated soil was amended with each of the wastes (10% w/w) using microcosm systems, which were monitored physico-chemically, microbiologically and toxicologically. Results indicate that the wastes promoted significant oil degradation, achieving 83.1, 90.7, and 86.2% removal for soybean texturized waste, spent mushroom substrate, and stabilized poultry litter, respectively, within a 90-day period. Additionally, they positively influenced soil microbial activity, as evidenced by increased levels of culturable microorganisms and hydrolytic microbial activity. While bioassays indicated no phytotoxicity in most cases, soybean texturized waste exhibited inhibitory effects on seed germination and root elongation of Lactuca sativa. This study significantly enhances our comprehension of remediation techniques for sites tainted with vegetable oils, highlighting the critical role of organic waste as eco-friendly agents in soil restoration. Emphasizing the practical implications of these findings is imperative to underscore the relevance and urgency of addressing vegetable oil contamination in soil. Moving forward, tailored strategies considering both contaminant characteristics and soil ecosystem traits are vital for ensuring effective and sustainable soil remediation.

Replacing traditional nursery soil with spent mushroom substrate improves rice seedling quality and soil substrate properties.

Currently, large quantities of spent mushroom substrate (SMS) are produced annually. Because SMS has high water retention and nutrients, it has great potential to replace traditional topsoil for raising seedlings in agricultural production. However, few studies have examined the effects of substituting SMS for paddy soil on rice seedling growth and soil nutrients. SMS was mixed with rice soil in different proportions (20%, 50%, and 80%), and chemical fertilizer, organic fertilizer, and peat substrate were added in addition to equivalent nitrogen as a traditional seedling nursery method for comparison. Compared to traditional paddy soil (CK), the seedling qualities of the three SMS ratio treatments were all higher. Adding SMS at different ratios promoted rice seedling root growth, elevated the soluble protein concentration, and amplified the superoxide dismutase (SOD) enzymatic action in rice seedlings. Total porosity and aeration porosity of the soil increased by 17.40% and 32.90%, respectively. Soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) increased by 21.26-118.48%, 50.44-71.68%, and 23.08-80.17%, respectively. Besides, the relative abundance of Bacillus, Bacteroidetes, and other bacteria as well as the abundance of Ascomycota were all significantly increased. Adding 50% SMS increased the abundance of Pseudomonas by 8.42 times. The seedling quality of the 50% SMS treatment was even higher than chemical fertilizer and organic fertilizer treatments, only second to the peat substrate treatment. In summary, partial substitution of paddy soil with SMS can ameliorate substrate properties, improve seedling quality, and increase microbial diversity, indicating the suitability of SMS as a replacement for rice soil in seedling substrates. The 50% SMS ratio is the best. This study provides a basis for SMS to replace traditional rice soil in seedling cultivation.

How Does a Decision-Making Tool Enhance Spent Mushroom Substrate Valorization into Polysaccharides?

In mushroom farming, one kilogram harvested results in about five kilograms of spent mushroom substrate (SMS), posing an environmental management challenge. As an in-tune work with the concepts of circular economy, cleaner production, and waste minimization, this study has developed a mathematical model than analyzes the valorization potential of SMS through polysaccharide production. The in-depth mathematical model is based on a system dynamics approach, which explains the interactive interplay amongst the production process, related costs, energy consumption, and caused emissions. The model has been developed in a generic way. Meaning that it can be re-adjusted flexibly for a different cleaner production process. A user-friendly interface has been developed. Users can easily maneuver around the variables within the model that offers instantaneous insight into the environmental and economic impacts of SMS valorization. This interface was later integrated into an educational context to serve as an interactive decision-making tool for cleaner production modelling. The main purpose of the developed tool was to favor understanding of causalities between production chains, energy consumption, labor, emissions, and expenses. This tool has been tested on master’s degree students in a cleaner production course. Survey results show that 82% of students report the need to incorporate similar decision-making tools in their learning curriculum. In sum, the application of system dynamics to the valorization of SMS does not only present an attractive solution for this environmental problem but also shows great potential in setting educational backgrounds for an interactive and close-to-life learning process. It is recommended to develop more interactive tools available for students.

Effect of the Replacement of Wheat Straw by Spent Mushroom Substrate in the Diet of Dairy Ewes during Late Lactation on Milk Production, Composition, Oxidation Stability and Udder Health

The aim of the present study was to investigate the effects of different dietary levels of spent mushroom substrate (SMS) at the expense of wheat straw (WS) on milk characteristics in dairy sheep. Thirty ewes at their final stage of lactation (145 ± 5 days after parturition) were randomly assigned into three groups; control (C), provided with a diet consisting of concentrates, alfalfa hay and WS, and SMS1 and SMS2, where WS was replaced by SMS at 50 or 100%, respectively. The experiment lasted for 28 days, and milk yield, composition, somatic cell count (SCC) and oxidative stability were monitored weekly, while milk fatty acid and immune cell profile were also determined on day 28. No significant differences were found in produced milk quantity, fat, protein, lactose, total solids non-fat, SCC and fatty acid profile between the experimental groups. However, milk oxidative stability was significantly improved as an effect of SMS (p &lt; 0.001). At the same time, milk polymorphonuclear leukocyte percentage was decreased in SMS2 group (p &lt; 0.05). As indicated, SMS seems to be a promising agro-industrial by-product for ewes’ diet that could improve milk oxidative stability, without negatively affecting milk yield, composition and ewe health status, contributing in the context of sustainability, circular economy and protection of natural resources.

Valorization of Spent Mushroom Substrate: Establishing the Foundation for Waste-Free Production

Spent mushroom substrate (SMS), often disregarded as waste despite its abundance in organic matter and mineral micronutrients, has emerged as a valuable resource for diverse applications. While Europe and Asia have witnessed extensive research in this field over the past decade, Ukraine’s exploration remains limited. This study conducts a thorough investigation into SMS recycling and reutilization over a 4-year period. Employing experimental and comparative methods, this research unveils compelling insights into the potential of SMS for reintroduction into the primary production cycle and secondary activities. The main conclusions reveal the success of SMS valorization in the production of additives, fertilizers, and alternative fuels. Furthermore, the application of SMS in agroecosystems significantly enhances the soil biological activity. The integration of these methods into production chains not only yields economic benefits for companies but also fosters environmental stewardship, aligning with waste-free practices and the principles of bioeconomy and sustainability.

Bioremediation of petroleum hydrocarbons polluted soil by spent mushroom substrates: Microbiological structure and functionality

Spent mushroom substrate (SMS) holds valuable microbiota that can be useful in remediating polluted soils with hydrocarbons. However, the microorganisms behind the bioremediation process remain uncertain. In this work, a bioremediation assay of total petroleum hydrocarbons (TPHs) polluted soil by SMS application was performed to elucidate the microorganisms and consortia involved in biodegradation by a metabarcoding analysis. Untreated polluted soil was compared to seven bioremediation treatments by adding SMS of Agaricus bisporus, Pleurotus eryngii, Pleurotus ostreatus, and combinations. Soil microbial activity, TPH biodegradation, taxonomic classification, and predictive functional analysis were evaluated in the microbiopiles at 60 days. Different metagenomics approaches were performed to understand the impact of each SMS on native soil microbiota and TPHs biodegradation. All SMSs enhanced the degradation of aliphatic and aromatic hydrocarbons, being A. bisporus the most effective, promoting an efficient consortium constituted by the bacterial families Alcanivoraceae, Alcaligenaceae, and Dietziaceae along with the fungal genera Scedosporium and Aspergillus. The predictive 16 S rRNA gene study partially explained the decontamination efficacy by observing changes in the taxonomic structure of bacteria and fungi, and changes in the potential profiles of estimated degradative genes across the different treatments. This work provides new insights into TPHs bioremediation.

Effect of substrate moisture content during cultivation of Hericium erinaceus and subsequent vermicomposting of spent mushroom substrate in a continuous feeding system

Cultivation of Hericium erinaceus depends on various factors, one of which is water content in the substrate. This parameter influences not only the growth rate of the mushroom but also enzymatic activity, which is important for substrate decomposition and for the later usage of spent mushroom substrate (SMS). This study compared parameters, such as mycelial growth, pH and enzymatic activity in substrates with different initial water content. During cultivation, the water content and pH decreased in all variants, but the activity of hydrolytic enzymes increased with time and was higher in variants with higher water content (70% and 75%); however, the activity of ligninolytic enzymes decreased during cultivation. The production of 1 kg of mushrooms generates about 5 kg of SMS. Vermicomposting is a natural method for processing SMS, as it involves a combination of earthworms, microorganisms and enzymatic activity; thus, we compared the differences between variants with and without earthworms using continuous feeding vermicomposters. The C:N ratio in the variant with earthworms radically decreased from 153.7:1 to 16.5:1. The ratio of bacteria to fungi in both variants was highest in the oldest compost layer in the vermicomposters. The variant without earthworms exhibited the highest enzymatic activity of β-D-glucosidase and Mn-peroxidase, but the highest activity of cellobiohydrolase and laccase occurred in the variant with earthworms. The vermicomposting process is ideal for this type of biowaste, as it produces a fertilizer rich in beneficial microorganisms and enzymatic activity.

Changes in soil organic carbon components and microbial community following spent mushroom substrate application.

While spent mushroom substrate (SMS) has shown promise in increasing soil organic carbon (SOC) and improving soil quality, research on the interplay between SOC components and microbial community following the application of diverse SMS types remains scant. A laboratory soil incubation experiment was conducted with application of two types of SMSs from cultivation of Pleurotus eryngii (PE) and Agaricus bisporus (AB), each at three application rates (3, 5.5, and 8%). Advanced techniques, including solid-state 13C nuclear magnetic resonance (NMR) and high-throughput sequencing, were employed to investigate on SOC fractions and chemical structure, microbial community composition and functionality. Compared to SMS-AB, SMS-PE application increased the relative abundances of carbohydrate carbon and O-alkyl C in SOC. In addition, SMS-PE application increased the relative abundance of the bacterial phylum Proteobacteria and those of the fungal phyla Basidiomycota and Ascomycota. The relative abundances of cellulose-degrading bacterial (e.g., Flavisolibacter and Agromyces) and fungal genera (e.g., Myceliophthora, Thermomyces, and Conocybe) were increased as well. The application of SMS-AB increased the aromaticity index of SOC, the relative abundance of aromatic C, and the contents of humic acid and heavy fraction organic carbon. In addition, SMS-AB application significantly increased the relative abundances of the bacterial phyla Firmicutes and Actinobacteria. Notably, the genera Actinomadura, Ilumatobacter, and Bacillus, which were positively correlated with humic acid, experienced an increase in relative abundance. Functional prediction revealed that SMS-PE application elevated carbohydrate metabolism and reduced the prevalence of fungal pathogens, particularly Fusarium. The application of high-rate SMS-AB (8%) enhanced bacterial amino acid metabolism and the relative abundances of plant pathogenic fungi. Our research provides strategies for utilizing SMS to enrich soil organic carbon and fortify soil health, facilitating the achievement of sustainable soil management.

Nitrogen-doped porous carbon with regulated pore structure and surface wettability as flow electrodes for efficient capacitive deionization

Nitrogen-doped porous carbon with controlled pore structure and wettability was synthesized using spent mushroom substrate (SMS) via physical activation process. The nitrogen-rich feature of precursor enables the carbon material to possess both electrical conductivity and surface wettability, creating an effective conducting network in flow electrodes. These materials have been proven to be highly efficient for deionization due to their ability of maintaining surface wettability and electrical conductivity. Our results show that the SMS-1.5 sample has a high adsorption capacity of 8.38 mg/g, which is 1.8 times greater than the commercial YP-50. The corresponding charge efficiency was up to 90.66 % after being exposed to 1.6 g/L NaCl feed solution for 120 min in flow electrode capacitive deionization device. This study highlights the significance of the inherent nitrogen element in biomass for the synergistic promotion of electrical conductivity and surface wettability, providing a strategy for designing porous carbons with excellent desalination performance.