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Zied DC, da Silva Freitas MA, de Almeida Moreira BR, da Silva Alves L, Pardo-Giménez A. A Comparative Analysis of Biodegradation and Bioconversion of Lentinula edodes and Other Exotic Mushrooms. Microorganisms 2023; 11:microorganisms11040897. [PMID: 37110320 PMCID: PMC10142386 DOI: 10.3390/microorganisms11040897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 04/03/2023] Open
Abstract
Mushrooms are capable of bioconverting organic residues into food. Understanding the relationship between high-quality yields and substrate biomass from these residues is critical for mushroom farms when choosing new strains. The objective of this exploratory study was, therefore, to analyze whether exotic mushrooms, namely, Pleurotus eryngii, Flammulina velutipes, and Agrocybe aegerita, could biologically convert the substrate into edible mushrooms as effectively as Lentinula edodes (baseline). Five experiments were carried out. Biological efficiency, biodegradability coefficient, mass balance and chemical characterization of the substrate were evaluated. Strategically hydrating the sawdust enabled L. edodes to achieve the greatest biodegradability and biological efficiency of 0.5 and 94.2 kg dt−1, respectively. The values for L. edodes on wheat straw without hydration were 0.2 and 68.8 kg dt−1, respectively. From 1000 kg of fresh substrate, P. eryngii produced 150.1 kg of edible mushrooms, making it technically competitive with L. edodes on wheat straw (195.9 kg). Hence, P. eryngii was the most reliable option for scaling among the exotic mushrooms. The analytical insights from our study provide further knowledge to advance the field’s prominence in high-throughput mushroom-producing systems, particularly for exotic mushrooms.
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Integration of Hydrothermal Carbonisation and Anaerobic Digestion for the Energy Valorisation of Grass. ENERGIES 2022. [DOI: 10.3390/en15103495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The integration of hydrothermal carbonisation (HTC) and anaerobic digestion (AD) can overcome some of the disadvantages of thermal or biological processing alone. This study aims to investigate integrated HTC-AD across a range of integration strategies and HTC processing temperatures (150 °C, 200 °C and 250 °C) to improve the energy conversion efficiency (ECE) of grass, compared to AD alone. The separation of hydrochars (HCs) for combustion and process waters (PWs) for digestion appears to be the most energetically feasible HTC-AD integration strategy, compared to HC or HTC-slurry AD. Hydrochars represent the greater energy carrier with between 81–85% of total energy output. The ECE of grass was improved from 51% to 97% (150 °C), 83% (200 °C) and 68% (250 °C) through integrated HTC-AD. Therefore, lower HTC processing temperatures yield more favourable energetics. However, higher HTC temperatures favour more desirable HC properties as a combustion fuel. The hydrochar produced at 250 °C (HC-250) displayed the highest HHV (25.8 MJ/kg) and fixed carbon: volatile matter ratio (0.47), as well as the greatest reduction in slagging and fouling potential (ash flow temperature > 1550 °C). Overall, integrated HTC-AD is an effective energy valorisation strategy for grass. A compromise exists between the quality of hydrochar and the energetic balance. However, at 250 °C the process remains energetically feasible (EROI = 2.63).
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Exploring Farm Anaerobic Digester Economic Viability in a Time of Policy Change in the UK. Processes (Basel) 2022. [DOI: 10.3390/pr10020212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The combination of a post-Brexit agricultural policy, the Global Methane Pledge announced during the last United Nations Climate Change Conference in Glasgow (COP26), and urgency of meeting climate goals means the UK has a unique opportunity to create an exemplar through recognition of the benefits of small-scale farm anaerobic digesters that valorise on-site wastes for renewable electricity and heat, cushioning agri-businesses against energy perturbations. To explore economic viability of farm-based biogas production, combinations of support levels, energy prices, capital cost, internal rate of return (IRR), and digestate value were analysed, employing a 550-cow dairy farm with access to other agricultural wastes. A 145 kWe system utilising 100% of CHP electricity (grid value: £0.1361 per kWh) and 70% of the heat (heating oil value: £0.055 per kWh) could achieve an IRR above 15.5% with a median electricity tariff of £0.1104 per kWh at a heat tariff from £0.0309 to £0.0873 per kWh thermal. Under a subsidy-free regime, the same system could achieve a 10% IRR with electricity prices in the range £0.149 to £0.261 per kWh. High fertiliser prices could increase digestate value, further improving viability. With late-2021 high energy prices, the technology approaches subsidy-free viability, but uptake is unlikely unless wider environmental and societal benefits of on-farm systems can be explicitly valued.
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