Waste Substrates Research Articles

Optimización de parámetros de cultivo de Pleurotus eryngii y desarrollo de cepas mejoradas por apareamiento de neohaplontes compatibles

Production parameters for cultivation of P. eryngii were established. With 21 days incubation, a substrate of wheat straw (45%), sawdust (20%), wheat bran (16%) and gluten (5%) packed in 3.5 kg bags produced higher BE (103%) than a cotton waste substrate (BE=74%). Cold treatment or scratching of substrate for induction of fruiting resulted unnecessary. Strains FQ and MB of P. eryngii were dedikaryotized by blending mycelium suspensions for 300 seconds and inoculation 50 µL of homogenate into solutions with 20 g/L glucose and peptone. In two dedikaryotization experiments, both component monokaryons (neohaplonts) were recovered from strains FQ and MB. Hybrids and reconstructed parental dikaryons were obtained by mating neohaplonts. The strains generated in the first dedikaryotization experiment were fruited. The parental strains produced lower BE (103, 84%) than reconstructed strains (183, 101%) and two hybrids (106, 174%). After a second dedikaryotization, 17 neohaplonts were mated to produce 3 reconstructed strains and 7 hybrids. Their growth curves were determined on 2 solid media (MEA agar and wheat). The Baranyi model showed the best adjustment to growth curves and allowed to separate them into statistically different groups and to calculate the corresponding kinetic parameters (μmax, λ) on MEA agar and wheat.

An Extracellular Pectinase from ISH16 Bacteria Isolated Induced by Coffee Pulp Waste Substrate

An α-1,4-glycosidic bonds galactoses pectin, mainly composed of a D-galacturonic acid chain, are important biomaterial widely used in industries. Utilizing this material, a bioprocess, including the biocatalysis pectinase, is often needed. Pectinase production was optimized in 7 days SSF at 37°C, and the pectinase activities were daily measured by the method of Somogy-Nelson. The optimum pectinase production was 0.166 U/ml on the fourth day SSF. Purification using open column ion exchange chromatography DEAE cellulose DE-52 resulted in 1030.9 folds of pectinase purity with a yield of 25.9%. The enzyme was at optimal activity at pH six and attended stable in the pH range of 5.5-8, while optimal activity at a temperature of 50°C and was stable in the range of 30-45°C. The pectinase activity increased by 120% with the addition of 10 mM Mg2+, and 95% retained when 10 mM Ca2+ was added. The presence of 10 mM Na+, K+, and Fe2+ resulted in a slight effect of activity at 85%, 83%, and 78%. However, it was strongly inhibited by 10 mM Al3+ and retained 25%. Based on the results above, the microbial utilization of coffee pulp waste by ISH16 bacteria pectinolytic is one opportunity to produce valuable pectinase with low-cost production, so comprehensive examination in large-scale production is needed too. In this paper, all research detail steps were described.

Substrate composition effect on the nutritional quality of Pleurotus ostreatus (MK751847) fruiting body

Underutilized palm oil waste (shaft and bunch) and sawdust supplemented with wheat and rice bran were used to cultivate mushrooms (Pleurotus ostreatus). Substrates were compounded following the designed protocol, bagged, and sterilized. Bags were inoculated with actively growing spawn, incubated at 28 ± 2 °C, ramified, and growth parameters were observed and recorded. The highest values were obtained in protein content of (19.14%) in the shaft supplemented with wheat bran, fat contents (1.70%) in the bunch alone, ash content of 10.10% and 9.59% in the fermented bunch, and bunch supplemented with wheat bran respectively. Bunch combined with sawdust gave the highest carbohydrate of 6.19%. Fermented bunch gave the highest value of vitamin A (2.21 UI/100g), E (5.71 UI/100g), and D (5.90 UI/100g). In the current study, it was shown that Pleurotus ostreatus cultivated on the palm waste substrate supplemented with rice bran and wheat bran produced better dietic quality mushrooms.

Process Development of Polyhydroxyalkanoates Production by Halophiles Valorising Food Waste.

Polyhydroxyalkanoates (PHA) is an emerging biodegradable plastic family that can replace a broad spectrum of conventional thermoplastics and is promising in the sustainable process development and valorization of organic waste. This study established a novel production system of PHA from food waste through halophilic microbial fermentation with spent medium recycling. The essential processing parameters for batch cultivation of Haloferax mediterranei were optimized for food waste substrate (a 40 g/L loading and 2.5 vvm of aeration), which achieved a yield of 0.3 g PHA/g COD consumed. A batch bioreactor system was developed, which produced 7.0 ± 0.7 g/L cell dry mass and 4.5 ± 0.2 g/L PHA with a 20% dissolved oxygen (DO) level. A DO above 50% saturation resulted in faster cell growth and similar cell mass production but 25% less PHA production. The spent saline medium, treated with H2O2 and rotary evaporation, was successfully reused for four consecutive batches and provided consistent PHA concentrations and product qualities.

The Use of Zinc-Bromine Battery Technology to Remove and Recover Zinc from Scrap and Waste Steel Resources

ZBBs have a high open circuit voltage (1.82 V), a high theoretical energy (> 400 W h-1 kg-1) and high demonstrated power densities (> 100 mW cm-2). Typically, ZBBs adopt a redox flow design involving the use of a Nafion membrane to separate aqueous zinc bromide anolyte and catholyte solutions [1]. In this study, the use of a membrane-free non-flow design was investigated for the purposes of recovering zinc from scrap and waste steel resources [2]. The rationale for this work stems from the greenhouse gas emissions produced by the iron and steel industry, which accounts for between 4-7 % of the anthropogenic CO2 emissions globally [3]. Blast furnace technology is likely to account for most stainless steel production in the coming decades, and therefore a transition to low-carbon and green steel production will require increased steel recycling rates and significantly improved waste and scrap management. To the best of our knowledge, this is the first time a zinc-bromine battery has been investigated for the recovery of materials rather than energy storage.Galvanization of steel is required to prevent rusting and degradation and involves coating the surface of steel in a protective layer of zinc. Galvanization processes account for over 50 % of global zinc consumption and by 2050 the demand for zinc will be 2.7 times greater than that of 2012 [4]. In order to enable recycling of scrap steel directly into blast furnaces, zinc is removed and recovered via mineral acid leaching. This method of recovery has a high zinc extraction efficiency but creates problematic waste streams and has poor energetic efficiency.In this work, the use of a membrane-free zinc-bromine battery has been studied for the purposes of extracting zinc from steel substrates and subsequently re-electroplating onto a conventional carbon foam electrode. The electrical performance of the cell was characterised by charge-discharge profiles and I-V curves. Zinc removal and recovery onto electrodes was characterised using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The work successfully demonstrates that ZBB technology could enable efficient and clean recovery of zinc from metal and waste substrates including scrap steel, slurries generated from basic oxygen steelmaking processes, and secondary vent dust from the primary steelmaking off gas streams. The cell studied in this work enabled dipping of zinc-containing steel substrates directly into the electrolyte solution without disassembly of the battery housing. In addition, the design involved the use of low-cost materials and reagents and potentially offers low balance-of-plant costs.The results show that zinc could be removed from steel surfaces during cell discharge with greater than 99.9 % yield. The Figure shows the extracted zinc could subsequently be re-electroplated onto a standard carbon foam electrode upon re-charging the cell. When a 0.5 V cut-off voltage was used upon discharge, the zinc was recovered selectively from the steel (see Fig. (a)); the surface elemental composition of the carbon electrode measured by EDS after charging was: carbon (26.79 wt%), oxygen (18.06 wt%), zinc (30.03 wt%) and bromine (25.11 wt%). Using a lower cut-off voltage (0.2 V) resulted in the co-extraction of iron from the substrate as well as zinc (see Fig. (b)); in this case, the elemental composition of the carbon electrode after charging was: carbon (27.53 wt%), oxygen (22.65 wt%), iron (4.72 wt%), zinc (24.44 wt%) and bromine (20.65 wt%). Provided a cut-off voltage of no less than 0.5 V was used for discharging, high purity zinc was recovered, and the cell showed good initial durability, with 30 cycles of charge-discharge demonstrated in this work.[1] S. Suresh, M. Ulaganathan, N. Venkatesan, P. Periasamy, P. Ragupathy, High performance zinc-bromine redox flow batteries: Role of various carbon felts and cell configurations. J. Energy Storage, 2018. 20: pp. 134-139.[2] S. Biswas, A. Senju, R. Mohr, T. Hodson, N. Karthikeyan, K. Knehr, A.G. Hsieh, X. Yang, B.E. Koel, D.A. Steingart, Minimal architecture zinc-bromine battery for low-cost electrochemical storage. Energy Environ. Sci., 2017. 10: pp. 114-120.[3] Iron and Steel Technology Roadmap: Towards More Sustainable Steelmaking, Energy Technology Perspectives, International Energy Agency, IEA Publications, Paris, 2020. https://www.iea.org/reports/iron-and-steel-technology-roadmap [accessed 12 April 2022].[4] K.S. Ng, I. Head, G.C. Premier, K. Scott. E. Yu, J. Lloyd, J. Sadhukhan. A multilevel sustainability analysis of zinc recovery from wastes. Resour. Conserv. Recycl., 2016. 113: pp. 88-105.Figure. SEM images showing the carbon foam zinc electrodes after charging the cell. (a) is an electrode when a discharge cut-off voltage of 0.5 V was used, (b) is an electrode when a discharge cut-off voltage of 0.2 V was used. Figure 1

Biowaste and by-products as rearing substrates for black soldier fly (Hermetia illucens) larvae: Effects on larval body composition and performance.

Black soldier fly (Hermetia illucens) larvae can convert biowaste and by-products into body mass high in protein (~40% dry matter, DM) and lipid (~30% DM). However, the type of rearing substrate also affects the larval body composition and thus its nutritional value. Hitherto, it remains unclear how and to what extent the larval body composition can be altered by the substrate. This study was therefore performed to examine the possibilities of modifying larval body composition using different rearing substrates. To investigate this, 5-days old larvae were reared for seven days on different locally available waste and by-products: brewer’s spent grain, mitigation mussels (Mytilus edulis), rapeseed cake, and shrimp waste meal (Pandalus borealis). Larval composition and performance were compared to larvae reared on a commercial chicken feed as well as a mixed feed (mixture of chicken feed and by-products, with a similar macronutrient composition to chicken feed). Larval body weight was recorded daily to determine growth over time whereas larvae and substrates were sampled at the start and end of the trial and analysed for their nutritional composition. The type of rearing substrate affected both larval body composition and growth performance. There was a clear relation between the nutritional composition of the substrate and larvae for certain fatty acids. Larvae reared on marine-based waste substrates contained a higher share of omega-3 fatty acids than larvae reared on the other substrates, indicating an accumulation of omega-3 fatty acids from the substrate. There was a strong positive linear correlation between the ash content in the substrate and larvae whereas larval lipid, protein, amino acid, and chitin content seemed more affected by larval development. Overall, this study showed that the rearing substrate affects larval composition and development, and that larval composition of certain nutrients can be tailored depending on further food and feed applications.

Elevating Phospholipids Production Yarrowia lipolytica from Crude Glycerol.

Phospholipids (PLs) are a class of lipids with many proven biological functions. They are commonly used in lipid replacement therapy to enrich cell membranes damaged in chronic neurodegenerative diseases, cancer, or aging processes. Due to their amphipathic nature, PLs have been widely used in food, cosmetic, and pharmaceutical products as natural emulsifiers and components of liposomes. In Yarrowia lipolytica, PLs are synthesized through a similar pathway like in higher eukaryotes. However, PL biosynthesis in this yeast is still poorly understood. The key intermediate in this pathway is phosphatidic acid, which in Y. lipolytica is mostly directed to the production of triacylglycerols and, in a lower amount, to PL. This study aimed to deliver a strain with improved PL production, with a particular emphasis on increased biosynthesis of phosphatidylcholine (PC). Several genetic modifications were performed: overexpression of genes from PL biosynthesis pathways as well as the deletion of genes responsible for PL degradation. The best performing strain (overexpressing CDP-diacylglycerol synthase (CDS) and phospholipid methyltransferase (OPI3)) reached 360% of PL improvement compared to the wild-type strain in glucose-based medium. With the substitution of glucose by glycerol, a preferred carbon source by Y. lipolytica, an almost 280% improvement of PL was obtained by transformant overexpressing CDS, OPI3, diacylglycerol kinase (DGK1), and glycerol kinase (GUT1) in comparison to the wild-type strain. To further increase the amount of PL, the optimization of culture conditions, followed by the upscaling to a 2 L bioreactor, were performed. Crude glycerol, being a cheap and renewable substrate, was used to reduce the costs of PL production. In this process 653.7 mg/L of PL, including 352.6 mg/L of PC, was obtained. This study proved that Y. lipolytica is an excellent potential producer of phospholipids, especially from waste substrates.

Remediation of Waste Engine Oil Contaminated Soil using Rhamnolipid based Detergent Formulation

The utilization of waste substrates for rhamnolipid synthesis is a worthy alternative to conventional substrates to reduce the production cost of rhamnolipids. Rhamnolipid produced by Pseudomonas aeruginosa gi |KP 163922| using waste engine oil as substrate was investigated in batch and semi-batch studies for soil bioremediation. Green liquid detergent formulations were prepared by using environment-friendly builder (sodium citrate) and filler (isopropyl alcohol). Rhamnolipid, a biosurfactant was utilized in place of chemical surfactant to prepare the liquid detergent formulation. The formulations at different rhamnolipid concentrations i.e., below critical micelle concentration (CMC), at CMC, and above CMC, were tested for soil remediation efficiency. Each detergent formulation was characterized based on emulsification index (EI24%), surface tension reduction, foam ability, and foam stability. The in-house rhamnolipid based formulations above CMC, recovered oil up to 82.02 ± 0.938 % from contaminated soil with maximum surface tension reduction and foam volume as 26.5 ± 0.412 mN/m and 51.10 ± 1.37 mL respectively. The proposed remediation strategy demonstrated that the recovery of oil is possible at room temperature conditions. The performance properties including detergency and foaming of rhamnolipid based liquid detergent formulations were also compared with commercial rhamnolipid and other detergents.

Enzyme synthesis from Aspergillus niger using solidstate fermentation of Agro - waste Substrates

Enzyme synthesis from Aspergillus niger using solidstate fermentation of Agro - waste Substrates

Potential Applications of Frass Derived from Black Soldier Fly Larvae Treatment of Food Waste: A Review.

The disposal of large amounts of food waste has caused serious environmental pollution and financial losses globally. Compared to alternative disposal methods (landfills, incineration, and anaerobic digestion), composting by black soldier fly larvae (BSFL) is a promising alternative for food waste management. Despite extensive research into larval biomass, another valuable by-product generated from BSFL composting is BSFL frass. However, limited information is available for its potential application. The applications of BSFL frass can be intensified by understanding its physicochemical characteristics, benefits, and challenges of BSFL frass derived from food waste. BSFL frass is harvested after 9–23 days of the experiment, depending on the substrate used in the composting process. The generated BSFL frass could exceed 33% of the original weight of the substrate. The physicochemical characteristics of BSFL frass are as follows: the temperature after harvest is 24 °C to 27 °C, pH is 5.6–8.0, moisture content is 30 to 72%, C/N ratio is 8:1 to 27:1, high nitrogen, phosphorus, and potassium (NPK) content, and low heavy metal content. This paper reviews the characteristics, benefits, and application of BSFL frass. It will also investigate the challenges of using food waste substrates to produce BSFL frass, as well as the best way to pre-treat the food waste substrate and post-treat the BSFL frass.

Preliminary Study of <i>Pleurotus ostreatus</i> (Jacq.) P. Kumm. Spent Mushroom Compost as Nutrient Supplement on the Shoot Induction of Fig Tissue Culture

Spent mushroom compost is identified as waste substrate. As the mushroom agriculture industry is growing rapidly, the production also increases and contributes to large amounts of spent mushroom compost annually. The conversion of spent mushroom compost as waste to wealth is a great concept that can give value to agricultural industry and solid waste management of mushroom cultivation. The use of SMC as nurient supplement may reduce the production cost for in vitro culture of fig plant. This research is to study the use of Pleurotus ostreatus (Jacq.) P. Kumm. spent mushroom compost (SMC) as a nutrient supplement of the media in shoot induction of fig plant. Nodal segment of fig’s stem was cultured in MS media supplemented with different concentrations of SMC. With presence of SMC, 10% SMC have the highest shoot proliferation (2.167 ± 1.169) and length of shoot (0.154 ± 0.060 cm). The study revealed that in presence of 10% of SMC could produce new shoots at a frequency which was comparable to the control (p<0.05; n=3; Tukey’s multiple range test). Among the different media combinations of plant growth regulators with SMC, 15 μM Kinetin with 10% SMC is the most effective treatment which gave maximum number of shoot proliferation (3.00 ± 1.27). 30 μM IAA with 10% SMC media have the highest leaves regenerated which were 1.33 ± 0.84. In conclusion, the SMC added in media for plant tissue culture had positive effect on shoot induction thus highlighted the potential of waste substrate of SMC to act as nutrient supplement for plant tissue culture.

Electrical Characteristics of Chitosan-Carrageenan Membrane Implementation and Salt Bridge in Microbial Fuel Cell Using Yeast Fermented Cassava Waste Substrate

A Microbial Fuel Cell (MFC) is an electrochemical system that generates energy utilizing waste as a substrate and the results of microbial metabolism processes. This research utilizes yeast fermented cassava waste as a substrate to determine the electrical characteristics of PEM in the form of a chitosan-carrageenan membrane and salt bridge. The cassava waste is from the waste produced in the manufacture of tapioca flour. A dual-chamber MFC made of acrylic with a size of 8x8x10 cm is used. Cassava waste substrate with carbon electrodes would be in the anode compartment, and seawater electrolyte with Cu(Ag) fiber electrodes would be in the cathode compartment. Each measurement holds ±250 ml in each compartment. The MFC system consists of 10 cells and is analyzed every hour for 120 hours using a multitester. According to the results of the research, cassava waste (liquid and onggok) can be used as a substrate in the MFC system, which has the potential to produce alternative electrical energy. Compared to salt bridges, the use of PEM in the form of chitosan-carrageenan membranes produces more significant and better electrical characteristics. However, the chitosan-carrageenan membrane is still less suitable in the long term than the salt bridge.

Biogas production from anaerobic co-digestion of sewage sludge and food waste in continuously stirred tank reactor

The purpose of current investigation was to explore the scope of integrating an anaerobic digester in a decentralized municipal wastewater treatment plant for in-situ treatment of household waste. The present work intends to identify the potential of sewage sludge and food waste for biogas generation. The study was conducted in lab scale continuous stirred tank reactor having a working volume of 6.5 L at mesophilic temperature. The paper mill sludge was used as inoculum and was stabilised using food waste substrate for initial 50 days in batch mode. Co-digestion of food waste (FW) and bio-flocculated sewage sludge (BFS) was performed using continuous feeding for maintaining OLR of 2.5 gVSL−1D−1at HRT of 4 days for 120 days. 2% FW and 98% BFS (by volume) was feeded in the reactor throughout the experimental duration. The highest VFA accumulation of 1902 mg L−1 were observed and maximum bio-methane yield was found to be 127.05 mLCH4 g−1 VSadded. The pH with current feeding ratio was found stable during the reactor operation without adding external alkalinity source.

Optimization of Submerged Fermentation Parameters for Enhanced Lipase Production from Newly Isolated Lipolytic Yeasts using Agro Waste Substrates

Fungi are currently recognized as the most preferred sources of lipase due to their ability to produce copious amount of extracellular lipase with lower production’s and extraction’s costs. Lipase production was carried out in agro wastes formulated-liquid fermentation media at 300C, at 130rpm, at initial pH of 7 for 96 hours using newly isolated LipA gene identified yeasts [Pichia kudriavzevii ENS1 [Accession No: OL546800], Candida orthopsilosis PMS3 [Accession No: OL546803] and Saccharomyces cerevisiae PMS8 [Accession No: OL546805] at inoculum size of 2%. Agrowastes such as Mango kernel and orange peel were used as alternative carbon sources; beans hull and groundnut shell as nitrogen sources while lipidic sources such as olive oil, soyabeans oil, palm oil, groundnut oil and coconut oil were used as inducers. Single factor optimization process was carried out to determine the effects of carbon sources, nitrogen sources, inducers, incubation time, inoculum size, pH and carbon: nitrogen ratio on lipase production and cell growth. Extraction by filtration, centrifugation and acetone precipitation; Quantitative lipase assay using titrimetric method and Cell growth by measuring optic density at 600nm were done. Proximate analysis of the agro-waste substrates showed higher percentage of carbohydrate and crude fat in mango kernel powder at 68.05±0.56% and 19.54±0.62% while groundnut shell recorded higher crude protein at 11.63±0.05%. Single factor optimization study showed optimum lipase production and cell growth at 50.83±1.18u/ml/min and 0.69±0.00[OD] with Candida orthopsilosis PMS3[Accession No: OL546803] using hot water treated mango kernel hydrolysate as carbon source. The results from this study showed that mango kernel would be an economical alternative carbon source for industrial-scale lipase production.

Spent coffee grounds anaerobic digestion: Investigating substrate to inoculum ratio and dilute acid thermal pretreatment

Spent coffee grounds have the potential of being used in further bioprocesses to produce materials and fuels. In Norway, the relative abundance and ease of collection of this waste substrate make it a candidate for investigation. For this study, the substrate-to-inoculum ratio as well as a combined dilute acid-thermal pretreatment were assessed by a series of biochemical methane potential assays using spent coffee grounds as a substrate. Reactors with substrate-to-inoculum ratio 2 demonstrated a relatively low hydrolysis rate constant (kh) and comparatively high volatile fatty acids/alkalinity concentrations rendering them inapt to produce bio-CH4. Pretreatment was conducted over varying contact times (15–45 min), dilute acid concentrations (1.5–2.5 %, v/v), and liquid-to-solid ratios (10–20 %, v/w) and evaluated using response surface methodology. To determine bio-CH4 yield, pretreatment time and the interaction between acid concentration and liquid-to-solid ratio are considered significant variables, suggesting a shared importance. Chemical oxygen demandremoval is primarily contingent upon changes in liquid-to-solid ratio. Finally, Fourier-transform infrared spectroscopy of the discarded solid phase showed that the major functional groups are still widely present in the coffee grounds even after pretreatment was applied. A better understanding of the biodegradability profile of spent coffee grounds as a function of substrate-to-inoculum ratio is achieved.

Traceability of insects as feed: stable isotope ratio analysis of Hermetia illucens larvae and pre-pupae reared on different protein sources

Insects attract the interest of the agri-food sector because of their advantages as feed for livestock. The reason for this lies in the role of insects as alternative protein source to soybean and fish meal, common but expensive materials, and in their ability to proliferate on waste substrates, thus allowing a sustainable livestock management. Insects for feed purposes can however be problematic, in particular with regard to the safety of the substrates the insects would be reared on. Therefore, effective tracking methods are needed. This study focused on the investigation, by means of isotope ratio mass spectrometry, of larvae and pre-pupae of Hermetia illucens L. (black soldier fly (BSF)) reared on diets including protein sources of vegetable origin (wheat gluten), animal origin (bovine blood meal), or a combination of the two, in order to detect differences in their isotope ratios for δ13C and δ15N. Nitrogen isotopic ratios did not follow an incremental pattern between diets, thus not allowing the discrimination of the BSF larvae and pre-pupae, presumably due to differences in the metabolism of insects that could have influenced the fractionation of nitrogen. In the case of the carbon isotopic ratio an increasing trend was observed, directly correlating the carbon isotopic signature of BSF larvae and pre-pupae to the level of replacement of the vegetable protein source with the animal one. According to our observations, it is therefore foreseeable that the study of carbon isotope ratios could be a promising method for the traceability of insects intended for animal feeding. Given the paucity of studies in this regard, further research effort is needed to fully explain some observation reported in the present study and to ascertain the reliability of the ratio analysis of insects as a tool for tracing their feeding history.

Sustainable bioconversion of agricultural waste substrates into poly (3-hydroxyhexanoate) (mcl-PHA) by Cupriavidus necator DSM 428

Sustainable bioconversion of agricultural waste substrates into poly (3-hydroxyhexanoate) (mcl-PHA) by Cupriavidus necator DSM 428

Organic Waste Substrates for Bioenergy Production via Microbial Fuel Cells: A Key Point Review

High-energy consumption globally has raised questions about the low environmentally friendly and high-cost processes used until now for energy production. Microbial fuel cells (MFCs) may support alternative more economically and environmentally favorable ways of bioenergy production based on their advantage of using waste. MFCs work as bio-electrochemical devices that consume organic substrates in order for the electrogenic bacteria and/or enzyme cultures to produce electricity and simultaneously lower the environmental hazardous value of waste such as COD. The utilization of organic waste as fuels in MFCs has opened a new research path for testing a variety of by-products from several industry sectors. This review presents several organic waste substrates that can be employed as fuels in MFCs for bioenergy generation and the effect of their usage on power density, COD (chemical oxygen demand) removal, and Coulombic efficiency enhancement. Moreover, a demonstration and comparison of the different types of mixed waste regarding their efficiency for energy generation via MFCs are presented. Future perspectives for manufacturing and cost analysis plans can support scale-up processes fulfilling waste-treatment efficiency and energy-output densities.

A Study on the Sound Absorption Properties of Mycelium-Based Composites Cultivated on Waste Paper-Based Substrates.

Mycelium-based composites have the potential to replace petrochemical-based materials within architectural systems and can propose biodegradable alternatives to synthetic sound absorbing materials. Sound absorbing materials help improve acoustic comfort, which in turn benefit our health and productivity. Mycelium-based composites are novel materials that result when mycelium, the vegetative root of fungi, is grown on agricultural plant-based residues. This research presents a material study that explores how substrate variants and fabrication methods affect the sound absorption properties of mycelium-based composites grown on paper-based waste substrate materials. Samples were grown using Pleurotus ostreatus fungi species on waste cardboard, paper, and newsprint substrates of varying processing techniques. Measurements of the normal-incidence sound absorption coefficient were presented and analyzed. This paper outlines two consecutive acoustic tests: the first round of experimentation gathered broad comparative data, useful for selecting materials for sound absorption purposes. The second acoustic test built on the results of the first, collecting more specific performance data and assessing material variability. The results of this study display that cardboard-based mycelium materials perform well acoustically and structurally and could successfully be used in acoustic panels.

Effects of cow manure rate on average weight of fresh fruit, B.E (%) of Pleurotus citrinopileatus on rubber sawdust and waste substrate after growing Ganoderma lucidum

Currently in Vietnam, Pleurotus citrinopileatus is grown on cellulose-rich substrates. Pleurotus citrinopileatus was grown on a substrate of rubber sawdust and waste substrate after growing Ganoderma lucidum. The cultivation of Pleurotus citrinopileatus mushroom on the waste substrate after growing Ganoderma lucidum is to take advantage of agricultural waste and to create edible mushroom products for the market. These substrates were rich in cellulose and were supplemented with cow manure at different ratios of 0%, 2%, 4%, 6%, and 8% to obtain the average weight of fresh fruit bodies per plant embryo bag and biological efficiency B.E (%). This study is for surveying the effect of cow manure rate on the average weight of fresh fruit, B.E (%) of Pleurotus citrinopileatus on two substrates, including rubber sawdust and waste residue, after growing Ganoderma lucidum.