Agricultural Substrates Research Articles

Physical and Mechanical Properties of Indian Oyster Mushroom Mycelium/Sawdust Composites for Biodegradable Packaging Materials

Mycelium-based composite (MBC) offers an excellent sustainable alternative to hydrocarbon-based materials, especially styrofoam for packaging, due to its abundance of fungal mycelium that grows quickly on agricultural substrates, its biodegradable and its lightweight. The mycelium of a commercial mushroom species, Pleurotus ostreatus (PO), is used to fabricate MBC for packaging materials. Another species, Pleurotus pulmonarius (PP), prefers warmer weather, making it more common in tropical countries. Nevertheless, there is a lack of studies of PP mycelium-based composites and their mechanical and physical properties. This study investigated the physical and mechanical properties of PP mycelium/sawdust composite and compared to PO mycelium/sawdust composite. The results showed that the average density of PP/sawdust and PO/sawdust composites were 292.14 and 272.17 kg/m3, respectively, which fell within the range of low-density polyurethane foam. The final mass gain due to water absorption into PO/sawdust specimens was 144.04%, 1.41 times lower than PP/sawdust specimens. Furthermore, PP/sawdust composite exhibited 7.5 times faster water absorption rate than PO/sawdust composite, indicating that PO/sawdust had better water resistance. The PP/sawdust composite produced an equivalent compressive modulus to the PO/sawdust composite under compression up to 1.34 MPa of maximum value. Thus, the PP/sawdust composite showed excellent potential for substitution of biodegradable packages made from PO/sawdust composite as they contributed the equivalent strength; however, the PO/sawdust composite exhibited superior water resistance to the PP/sawdust composite. Consequently, PO/sawdust should be more advantageous if the biodegradable packaging is required to be of strength as high as the low-density polyurethane foam and of compatible water resistance.

Cross-environmental cycling of antimicrobial resistance in agricultural areas fertilized with poultry litter: A one health approach

Poultry litter, commonly used as an organic fertilizer, can contain antimicrobial residues, resistant bacteria, and/or antimicrobial resistance genes. After application to soil, these contaminants can reach crops and be transported to aquatic systems through leaching and runoff. Once in water bodies, they can return to soil and crops through irrigation, establishing a cycle that promotes the selection, spread and persistence of antimicrobial resistance. To investigate the hypothesis of a cyclical event, samples of poultry litter, cultivable soil fertilized with this organic residue, rhizosphere soil from Sechium edule (chayote), water, and sediments from irrigation ponds were collected across two agricultural and poultry-producing areas during the dry and rainy seasons. Clinically significant bacteria, especially bacteria belonging to the Enterobacteriaceae family, were isolated. Fifty-three strains exhibited one or more antimicrobial resistance genes, as detected by PCR amplification, including those conferring resistance to sulfonamides (sul1 and sul2), fluoroquinolones (qnrB, qnrA, and qnrS), and β-lactams (blaGES, blaTEM, blaSHV, blaCTX-M-1/2,blaCTX-M-8, and blaCTX-M-14). Genes encoding integrases related to class-1 and 2 integrons (intI1 and intI2) were also observed. A rare occurrence of the blaGES gene was observed in Stenotrophomonas sp. and Brevundimonas sp. Strains of Escherichia sp. were multidrug resistant. Sequencing of the 16S rRNA encoding gene indicated unique operational taxonomic units (OTUs) originating from poultry litter and found in the soil, rhizosphere, water, and sediment, highlighting the dissemination of this material across agricultural substrates. These findings strongly suggest the spread of antimicrobial-resistant bacteria in agricultural environments, posing potential risks to both human and animal health.

Effect of agricultural substrates mixtures on yield and components in oyster mushroom (Pleurotus ostreatus)

Effect of agricultural substrates mixtures on yield and components in oyster mushroom (Pleurotus ostreatus)

Investigating Methane, Carbon Dioxide, Ammonia, and Hydrogen Sulphide Content in Agricultural Waste during Biogas Production

The agricultural industry produces a substantial quantity of organic waste, and finding a suitable method for disposing of this highly biodegradable solid waste is a difficult task. The utilisation of anaerobic digestion for agricultural waste is a viable technological solution for both renewable energy production (biogas) and waste treatment. The primary objective of the study was to assess the composition of biogas, namely the percentages of methane, carbon dioxide, ammonia, and hydrogen sulphide. Additionally, the study aimed to quantify the amount of biogas produced and determine the methane yield (measured in NmL/g VS) from different agricultural substrates. The biochemical methane potential (BMP) measurements were conducted in triplicate using the BPC Instruments AMPTS II instrument. The substrates utilised in the investigation were chosen based on their accessibility. The substrates used in this study comprise cattle manure, chicken manure, pig manure, tomato plants, tomatoes, cabbage, mixed fruits, mixed vegetables, dog food, and a co-digestion of mixed vegetables, fruits, and dog food (MVMFDF). Prior to the cleaning process, the makeup of the biogas was assessed using the BIOGAS 5000, a Geotech Analyser. The AMPTS II flow cell automatically monitored and recorded the volume of bio-methane produced after the cleaning stage. The data were examined using the Minitab-17 software. The co-digestion of mixed vegetables, mixed fruits, and dog food (MVMFDF) resulted in the highest methane level of 77.4%, followed by mixed fruits at 76.6%, pig manure at 72.57%, and mixed vegetables at 70.1%. The chicken manure exhibited the greatest levels of ammonia (98.0 ppm) and hydrogen sulphide (589 ppm). Chicken manure had the highest hydrogen sulphide level, followed by pig manure (540 ppm), tomato plants (485 ppm), mixed fruits (250 ppm), and MVMFDF (208 ppm). Ultimately, the makeup of biogas is greatly affected by the unique qualities of each substrate. Substrates containing elevated quantities of hydrogen sulphide, such as chicken manure, require the process of biogas scrubbing. This is because they contain substantial amounts of ammonia and hydrogen sulphide, which can cause corrosion to the equipment in biogas plants. This emphasises the crucial need to meticulously choose substrates, with a specific focus on their organic composition and their capacity to generate elevated methane levels while minimising contaminants. Substrates with a high organic content, such as agricultural waste, are optimal for maximising the production of methane. Furthermore, the implementation of biogas scrubbing procedures is essential for efficiently decreasing carbon dioxide and hydrogen sulphide levels in biogas. By considering and tackling these problems, the effectiveness of biogas generation can be enhanced and its ecological consequences alleviated. This strategy facilitates the advancement of biogas as a sustainable energy source, hence contributing to the attainment of sustainable development goals (SDGs).

Elevating Sorghum Prosperity: Unveiling Growth Trends through Phosphate-Solubilizing Bacteria and Arbuscular Mycorrhizal Fungi Inoculation in Phosphate-Enriched Substrates

This study aimed to elucidate the impact of phosphate-solubilizing bacteria (PSB) and arbuscular mycorrhizal fungi (AMF) inoculation on sorghum growth within substrates derived from phosphate solid sludge, with the overarching objective of repurposing phosphate sludge to be a viable agricultural substrate. Four PSB strains (Serratia rubidaea, Enterobacter bugandensis, Pantoea agglomerans, Pseudomonas sp.) were meticulously selected from phosphate solid sludge, along with two AMF strains (Rhizophagus intraradices and Funneliformis mosseae), constituting the experimental inocula. Phosphate solid sludge was judiciously blended with peat at varying volumetric proportions (0%, 10%, 20%, 40%, and 60%), providing the matrix for sorghum cultivation, and concomitantly subjected to inoculation with PSB and AMF. Following a meticulously monitored two-month duration, a comprehensive evaluation of diverse morphological parameters, biomass accrual, nitrogen content, total phosphorus concentration, potassium levels, calcium content, and root colonization in sorghum plants was conducted. The empirical findings underscored a discernible decline in the assessed parameters with escalating concentrations of phosphate solid sludge. Particularly noteworthy was the pronounced amelioration observed in plants inoculated with AMF in comparison to both the control and PSB-inoculated counterparts. In conclusion, the application of raw phosphate solid sludge as an agricultural substrate is deemed unsuitable, prompting the imperative need for further in-depth investigations to ascertain the nuanced intricacies underlying these outcomes.

Usability of Zea mays and Sorghum bicolor on the growth and yield of oyster mushrooms

In this research, three agricultural substrates, Zea mays, Sorghum bicolor Horse S, and Sorghum bicolor Giza 115, were evaluated as growing media in commercial mushroom cultivation. Zea mays waste had the highest moisture content with a relatively high nitrogen, phosphorus, potassium, protein, and energy value compared with Sorghum bicolor Horse S and Sorghum bicolor Giza 115, so the results indicate that Zea mays waste cultivated with different species of Pleurotus tested gave high-production oyster mushrooms with the highest biological efficiency and also a high total number of fruit bodies. P. floridans cultivated in Zea mays waste gave the best production by 182 gm, biological efficiency of 36.4%, and also a high number of fruit bodies (28) followed by P. pulmonarius on Sorghum bicolor Horse S waste, which gave production by 180 gm and also a high number of fruit bodies (27).

PROCEDURE TO GROW FUNGI-BASED BIODEGRADABLE INSULATING PANELS FOR THE CONSTRUCTION INDUSTRY

ABSTRACT This work tackles the development of green biocomposite insulating panels out of fungi mycelia and to replace petroleum-based foam-expanded polystyrene (EPS) panels. These biological prototypes have advantages over expanded polystyrene foam panels, since they do not pollute, they are not flammable, and they are 100% biodegradable. They have been developed growing Pleurotus ostreatus (oyster mushroom) and Lentinula edodes (Shiitake) mycelia on different agricultural substrates inside different types of moulds (up to 21 × 30 cm). As a result, the most suitable combinations of fungi species and agricultural substrates have been determined to grow biological insulating panels. Prototypes obtained were subjected to accelerated ageing tests to evaluate their resistance and changes in durability against water filtration and humidity changes in the event that they are used as insulating panels. Some technological properties have also been determined to evaluate their use as construction materials. The results obtained allow us to claim that biodegradable fungi-based insulating panels are viable to replace polluting foam-based insulating panels for the construction industry.

Effects of marine sediment as agricultural substrate on soil microbial diversity: an amplicon sequencing study

BackgroundThe soil microbiota has a direct impact on plant development and other metabolic systems, such as the degradation of organic matter and the availability of microelements and metabolites. In the context of agricultural soils, microbial activity is crucial for maintaining soil health and productivity. Thus, the present study aimed to identify, characterize, and quantify the microbial communities of four types of substrates with varying proportions of marine port sediment used for cultivating lemons. By investigating microbial diversity and relative abundance, the work aimed to highlight the importance of soil microbial communities in agriculture when alternative culture media was used.ResultsThe composition and structure of the sampled microbial communities were assessed through the amplification and sequencing of the V3-V4 variable regions of the 16 S rRNA gene The results revealed a diverse microbial community composition in all substrate samples, with a total of 41 phyla, 113 classes, 266 orders, 405 families, 715 genera, and 1513 species identified. Among these, Proteobacteria, Bacteroidota, Planctomycetota, Patescibacteria, Chloroflexi, Actinobacteriota, Acidobacteriota, Verrucomicrobiota, and Gemmatimonadota accounted for over 90% of the bacterial reads, indicating their dominance in the substrates.ConclusionsThe impact of the substrate origin on the diversity and relative abundace of the microbiota was confirmed. The higher content of beneficial bacterial communities for plant development identified in peat could explain why is considered an ideal agricultural substrate. Development of “beneficial for plants” bacterial communities in alternative agricultural substrates, regardless of the edaphic characteristics, opens the possibility of studying the forced and specific inoculation of these culture media aiming to be agriculturally ideals.

Performance of Edible Mushroom Varieties Under Different Agricultural Substrates

The study was conducted at Dr. Emilio B. Espinosa, Sr. Memorial State College of Agriculture and Technology (DEBESMSCAT) Cabitan, Mandaon, Masbate. The experimental design used was 3 x 7 CRD factorial with three varieties of mushrooms (Pink Oyster, White Abalone, and Milky Mushroom), seven agricultural substrates as treatments, Treatment A (70% rice straw and 30% sawdust), Treatment B (70% rice straw and 30% corn cob), Treatment C (70% rice straw and 30% Carbonized Rice Hull), Treatment D (100% rice straw), Treatment E (100% sawdust), Treatment F (100% corn cob) and Treatment G (100% Carbonized Rice Hull). The experiment was replicated three times with a total of 945 fruiting bags. Height, fresh weight, and the number of fruiting bodies are the data that was observed in the study. The result showed that in terms of growth performance, a nonsignificant result was observed in the height performance of the mushroom varieties inoculated in substrates with 70% rice straw, 30% corn cob, and 100% carbonized rice hull. Similarly, the number of mushroom fruiting bodies produced differed among mushroom varieties inoculated. Mushrooms inoculated in 100% carbonized rice hull attained more fruiting bodies than other tested varieties. Mushrooms inoculated in 100% corn cob produced a significantly higher number of mushroom fruiting bodies than other treatments. Finally, the weight of mushroom fruiting bodies produced in 70% rice straw and 30% carbonized rice hull applications was statistically significant for all agricultural substrates inoculated. The researcher concluded that using agricultural substrates other than carbonized rice is effective in mushroom production.

Pretreated Eucalyptus globulus and Pinus radiata Barks: Potential Substrates to Improve Seed Germination for a Sustainable Horticulture

Commercial forest plantations in Chile are dominated by pine (Pinus radiata) and eucalyptus (Eucalyptus globulus). Tree bark is the main by-product of the forestry industry and has low value, but great potential for use as an agricultural substrate. However, the direct use of bark fibers may cause plant phytotoxicity due to the presence of polyphenolic and other compounds. This study aims to evaluate the physicochemical properties of E. globulus and P. radiata bark after water extraction treatments. The phytotoxicity of the resulting extracted bark alone and that mixed with commercial substrates (coconut fiber, moss, peat, and composted pine) at different ratios (25 to 75 wt%) were assessed using the Munoo-Liisa vitality index (MLVI) test. For all treatments, the seed germination and growth of radish (Raphanus sativus) and Chinese cabbage (Brassica rapa) species were evaluated and compared to a commercial growing medium (peat) as a control. The optimal mixture for seed growth was determined to be 75% extracted E. globulus bark fiber and 25% commercial substrates such as peat (P), coconut fiber (C), moss (M), and composted pine (CP), as indicated by the MLVI and germination results. Two phytostimulant products, chitosan and alginate-encapsulated fulvic acid, were added to the best substrate mixture, with the purpose of improving their performance. Encapsulated fulvic acid at 0.1% w/v was effective in promoting plant growth, while chitosan at all of the concentrations studied was effective only for mixture 75E-25CP. The mixture of E. globulus fiber and commercial substrates, containing a high proportion of water-extracted fiber (75%), shows the potential to be used in the growth of horticultural crops and in the plant nursery industry.

Effect of Some Agricultural Substrates on Production Efficiency of Lentinula edodes (OM432157) and Evaluation of its Vitamins Content

Effect of Some Agricultural Substrates on Production Efficiency of Lentinula edodes (OM432157) and Evaluation of its Vitamins Content

The transcriptional activator ClrB is crucial for the degradation of soybean hulls and guar gum in Aspergillus niger

Low-cost plant substrates, such as soybean hulls, are used for various industrial applications. Filamentous fungi are important producers of Carbohydrate Active enZymes (CAZymes) required for the degradation of these plant biomass substrates. CAZyme production is tightly regulated by several transcriptional activators and repressors. One such transcriptional activator is CLR-2/ClrB/ManR, which has been identified as a regulator of cellulase and mannanase production in several fungi. However, the regulatory network governing the expression of cellulase and mannanase encoding genes has been reported to differ between fungal species. Previous studies showed that Aspergillus niger ClrB is involved in the regulation of (hemi-)cellulose degradation, although its regulon has not yet been identified. To reveal its regulon, we cultivated an A. niger ΔclrB mutant and control strain on guar gum (a galactomannan-rich substrate) and soybean hulls (containing galactomannan, xylan, xyloglucan, pectin and cellulose) to identify the genes that are regulated by ClrB. Gene expression data and growth profiling showed that ClrB is indispensable for growth on cellulose and galactomannan and highly contributes to growth on xyloglucan in this fungus. Therefore, we show that A. niger ClrB is crucial for the utilization of guar gum and the agricultural substrate, soybean hulls. Moreover, we show that mannobiose is most likely the physiological inducer of ClrB in A. niger and not cellobiose, which is considered to be the inducer of N. crassa CLR-2 and A. nidulans ClrB.

Plant growth promotion of the forage plant Lupinus albus Var. Orden Dorado using Pseudomonas agronomica sp. nov. and Bacillus pretiosus sp. nov. added over a valorized agricultural biowaste.

The overexploitation of natural ecosystems and the evolution of climate change currently force us to design new strategies for more sustainable agronomic uses. The recovery of plant residues, as an alternative to agrochemicals, can help alleviate these problems, for example, through its use for the synthesis of biofertilizers. In this work, the effect of the organic fertilizer matrix ORGAON® from the valorization of horticultural waste is tested, to which two strains of bacteria (and their consortium) are added (SAICEU11T identified as Bacillus pretiosus and SAICEU22T identified as Pseudomonas agronomica), selected for their demonstrated ability to promote plant growth (PGPB), on the lupine forage plant (Lupinus albus). For the synthesis of the biofertilizer, both strains were added to the ORGAON® organic matrix separately, until reaching a final optical density (OD) of 0.5 McFarland in each case in the irrigation matrix. As a control, sterile ORGAON® (ORGAON®st) was used, also supplemented with the PGPB strains and a chemical fertilizer widely used in agronomy (Chem-F). With these treatments, a 6-week experiment was started under controlled laboratory conditions and on agricultural substrate, to recreate field conditions as accurately as possible. All the tests were carried out with 9 repetitions and 3 replicates of each treatment. After harvest, the improvements on the following biometric variables were studied for each treatment: total weight (Weight_T, g), shoot weight (Weight_S, g), root weight (Weight_R, g), number of leaves (Leaves, No.), shoot length (Length_S), root length (Length_R) and number of secondary roots (Roots, No.). Likewise, the identification of the tested strains and their description as new species was carried out. For this, they were studied from the phenotypic point of view (Transmission electron microscopy (TEM), metabolic profile, PGP activities, fatty acid profile and Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)) and genotypic (sequencing of the main housekeeping genes and sequencing of the whole genome, genomic characteristics (dDDH and ANI) and phylogenetic analysis). After the statistical analysis of the results, it is shown that the individual addition of both strains on the ORGAON® and ORGAON®st organic matrix improve certain biometric variables. In the case of the SAICEU11T (Bacillus pretiosus) strain, the variables root weight (Weight_R, g), total weight (Weight_T, g) and length of the plant, and number of secondary roots (Roots, No.) significantly improve, while in the case of the strain SAICEU22T (Pseudmonas agronomica), a significant improvement of root length (Length_R) and number of secondary roots (Roots, No.) is demonstrated. On the other hand, the genotaxonomic analysis showed that both species have not been described to date. The identification based on the main housekeeping genes, show that for the Bacillus strain (SAICEU11T) the sequence similarity of the 16S rRNA was 100%, gyrB 92.69%, rpoB 97.70% and rpoD 94.67%. For the Pseudomonas strain (SAICEU22T) the results were 100% for 16S rRNA, 98.43% for rpoD and 96.94% for gyrB. However, in both cases, the dDDH and ANI values, as well as the phylogenetic analysis, show that both species are below the species threshold, which would support the hypothesis that both are new species, in line with the chemotaxonomic results obtained by MALDI-TOF spectrometry and fatty acid profile. To verify the biosafety in their handling and release into the natural environment, we have ruled out the presence of genes that encode virulence factors or resistance to antibiotics, concluding that they are suitable for use in the field to improve the yield of crop plants. Type strains are SAICEU11T (= DSM 114702T = CECT30674T) for Bacillus pretiosus and SAICEU22T (= DSM 114959T = CECT30673T) for Pseudomonas agronomicae.

Metabolomic Approach to Study the 'Purple Queen' Pomegranate Cultivar Response to Alternative Culture Media and Phenological Stages.

The increasingly evident threat of depletion of world peat bogs is encouraging the search for and study of alternative agricultural substrates that can fully or partially replace peat, guaranteeing food supply (quality and quantity). On the other hand, the identification of the potential for the reuse of waste from relevant economic activities has increased in recent years, mainly motivated by the change to a sustainable circular economy, as is the case of port sediments. Taking into account that significant volumes of dredged port sediments are generated annually so that ports can maintain their economic activity, it is necessary to find objective, sustainable and safe reuse alternatives. In this sense, the objective of this study was to study the response of the "Purple Queen" pomegranate when grown with dredged port sediment. For this, the fruit production (kg), number of fruits (fruits tree-1), fruit weight (g), and seed yield (%) aiming to verify the correct tree development were evaluated. In addition, a 1H-NMR foliar metabolomic study for the three most relevant phenological phases was performed (flowering, fruit development, and post-harvest) to identify metabolic changes in trees. In total, 29 metabolites were identified; among them, 11 were amino acids, 6 organic acids, 5 sugars, and 7 secondary metabolites. The good agronomical development of the trees and fruits indicated the potential for using the dredged sediment as an agricultural substrate. On the other hand, the results revealed that the greatest variability in the metabolomic study occurred between the phenological phases and a lower variability is explained by the substrates used.

Catalytic properties of purified alpha amylase from Aspergillus flavus cultivated on low-cost agricultural substrate

Aspergillus flavus isolated from fermented millet flour produced a crude enzyme, which was purified via ammonium sulphate precipitation and subsequent chromatographic techniques. The biochemical characteristics of the purified amylase were thereafter investigated showing activity in a wide range of pH and temperature, with optimal conditions of pH 6.0 and 50 °C. The enzyme retained even 89% of its activity after 1 h at 50 °C and 2 h at pH 6.0. The purified enzyme was stimulated by Ca2+, Zn2+ and Co2+, while Hg2+ and EDTA caused mild inhibition of α-amylase activity. The kinetic indices (Km and Vmax) and molecular weight of the enzyme were estimated in 1.71 mg mL-1, 2.133 μmol min-1 mL-1 and 45 kDa respectively. The catalytic properties of α-amylase from A. flavus makes it a promising candidate for use in various starch processing industries.

Environmental Risk from Organic Residues

Soil nutrient imbalance is a global threat to food security and ecosystem sustainability but adding organic residues or constructing anthropogenic soils and technosols can optimize it. However, FAO considers organic residues not “risk-free”, mainly due to their heavy metal content. Despite the fact that applying pruning residues to soil is a worldwide fertilization practice, its potential heavy metal risk has been poorly studied. This work characterizes Cu, Zn, Cd, Cr, Ni and Pb elemental composition concentration and their solubility content in almond tree pruning, commercial peat substrate, hay straw, olive tree pruning, pomegranate peel, pine needle, date palm leaf pruning, sewage sludge compost and vine pruning. Furthermore, we compare the legal frameworks governing heavy metal content in agricultural substrates to heavy metal concentration in each residue. Results show that commercial peat substrate is the only one among those studied that surpasses the threshold value for Cr in agricultural substrates. All pruning residues met the heavy metal threshold value; hence, their application to soil involves minimal soil toxicity. Moreover, the solubility index of heavy metals and the maximum quantity of each residue are crucial to discerning a heavy metal-free organic fertilization plan.

Great expectations—future scenarios for production and use of biogas and digestate in Sweden

Sweden aims to increase biogas production from anaerobic digestion (AD) from 2 to 7 TWh/year until 2030. This paper investigates the requirements, challenges and implications of such a development through qualitative and quantitative assessment of three scenarios. Seven key elements—national policies and policy instruments, regional policies and policy instruments, mobilization of feedstock, infrastructure for feedstock and gas, mobilization of actors, new production facilities, and stable and increasing demand—were defined for the scenario construction and were also used to structure the comparative analysis. Quantitatively, increasing the biogas production from 2 to 7 TWh is estimated to require up to 5 times larger digester volume and up to 12 times more AD plants, meanwhile producing 6–8 times more biofertilizers. While a centralized production structure would be more efficient, a decentralized structure with small biogas plants would facilitate the logistics of agricultural substrates and biofertilizers. New production capacity could be incentivized through new and increased production subsidies, as well as an increased demand for renewable energy. Regardless of how the goal is to be achieved, it will require collective efforts from both public and private actors to overcome the many challenges on the way.

Dynamics of water imbibition through hydrogel-coated capillary tubes

Capillary flow through hydrogel-coated capillary tubes was investigated experimentally and theoretically. The results show how the absorption and swelling of hydrogel regulate capillary flow. Water imbibition through porous hydrogel materials can be understood as analogous to flow through a channel that deforms with water absorption. Therefore, this study provides a better understanding of water absorption through porous hydrogel materials, which are widely used for agricultural substrates, hygienic products, and microfluidic devices.

Biogas and Biomethane Production and Usage: Technology Development, Advantages and Challenges in Europe

In line with the low-carbon strategy, the EU is expected to be climate-neutral by 2050, which would require a significant increase in renewable energy production. Produced biogas is directly used to produce electricity and heat, or it can be upgraded to reach the “renewable natural gas”, i.e., biomethane. This paper reviews the applied production technology and current state of biogas and biomethane production in Europe. Germany, UK, Italy and France are the leaders in biogas production in Europe. Biogas from AD processes is most represented in total biogas production (84%). Germany is deserving for the majority (52%) of AD biogas in the EU, while landfill gas production is well represented in the UK (43%). Biogas from sewage sludge is poorly presented by less than 5% in total biogas quantities produced in the EU. Biomethane facilities will reach a production of 32 TWh in 2020 in Europe. There are currently 18 countries producing biomethane (Germany and France with highest share). Most of the European plants use agricultural substrate (28%), while the second position refers to energy crop feedstock (25%). Sewage sludge facilities participate with 14% in the EU, mostly applied in Sweden. Membrane separation is the most used upgrading technology, applied at around 35% of biomethane plants. High energy prices today, and even higher in the future, give space for the wider acceptance of biomethane use.

Growth and Yield Performance of Oyster Mushroom Cultivated in Combined Cassava Peels, Coconut Residue and Coffee Waste Substrates

The oyster mushroom (Pleurotus ostreatus) is an edible mushroom that belongs to the class of Basidiomycetes. It has reached sufficient market maturity because of its flavor, shelf-life durability, and protein and fiber content. Besides their nutritional, medicinal, and economic value, they may help the country’s agricultural waste management, bridge environmental issues, and contribute to climate change resolution advancements. A study on different varieties of agricultural substrates derived from waste materials such as cassava peels, coconut residue, and coffee waste was investigated and compared to sawdust, the common substrate for oyster mushrooms. The effects of different substrates on the morphological characteristics of P. ostreatus, percent contamination, and yield parameters were recorded and analyzed using the Analysis of Variance in Completely Randomized Design, and their significant results were compared using Tukey’s HSD. Results showed that different substrate mixtures did not significantly influence the morphological characteristics of P. ostreatus. Moreover, sawdust, the common substrate for oyster mushrooms, showed the lowest percent contamination as compared to other substrate mixtures. Contaminants found in cassava substrates include Trichoderma spp., Aspergillus spp., Fusarium spp., Neurospora spp., and Penicillium spp. 80% of cassava peels combined with 10% coconut residue and 10% coffee waste significantly increased the number of fruiting bodies and produced the heaviest fresh weights of oyster mushrooms. Stipe length and pileus diameter were also significantly influenced by this substrate mixture, which is comparable to the common substrate. However, further research on the varying proportions of these substrate mixtures on the performance of oyster mushrooms is recommended.