Catalytic production of low-carbon footprint sustainable natural gas

Natural gas is one of the foremost basic energy sources on earth. Although biological process appears as promising valorization routes to transfer biomass to sustainable methane, the recalcitrance of lignocellulosic biomass is the major limitation for the production of mixing gas to meet the natural gas composition of pipeline transportation. Here we develop a catalytic-drive approach to directly transfer solid biomass to bio-natural gas which can be suitable for the current infrastructure. A catalyst with Ni2Al3 alloy phase enables nearly complete conversion of various agricultural and forestry residues, the total carbon yield of gas products reaches up to 93% after several hours at relative low-temperature (300 degrees Celsius). And the catalyst shows powerful processing capability for the production of natural gas during thirty cycles. A low-carbon footprint is estimated by a preliminary life cycle assessment, especially for the low hydrogen pressure and non-fossil hydrogen, and technical economic analysis predicts that this process is an economically competitive production process.

Solid Biofuels Scenarios from Rural Agricultural and Forestry Residues for Mexican Industrial SMEs

In Mexico, as in the rest of the world, the industry sector is frequently highly dependent on fossil fuels; in addition, energy transformation processes are not very efficient and scarcely oriented towards climate change mitigation. Given these facts, solid biofuels (SBFs) from agricultural and forestry residues from rural areas may represent an alternative that contributes to the decarbonization of the industrial sector, especially in Small- and Medium-Sized Enterprises (SMEs). From an economic and climate change mitigation perspective, this study evaluates harnessing SBFs in SMEs related to lime, bricks, dairy products, craft beer, and artisanal mezcal (a well-known Mexican distilled alcoholic beverage), products mainly manufactured in rural areas of Mexico. For each of these SMEs, we constructed two energy consumption scenarios that span from 2018 to 2050. On the one hand, a baseline scenario (BS) that reflects the behaviour of historical energy consumption in Mexico and, on the other hand, an alternative scenario (AS) that proposes the use of SBFs with modern and efficient technologies and sustainable inputs of agricultural and forestry residues originated mainly from rural areas. According to our results, a comparison between the two scenarios reveals that two out of five SMEs industrial niches studied, appear with mitigation costs in the AS namely brick kilns, and limekilns SMEs that have mitigation costs of 9.99 and 19.74 USD/tCO2e, respectively, primarily due to the high investment cost of the new MK2 kilns and the relatively high cost of pellets, respectively. Since these niches have high mitigation potentials (7.77 MtCO2e for brick kilns and 2.83 MtCO2e for limekilns), their implementation requires adequate incentives and financing. On the contrary, the dairy, craft beer, and mezcal SMEs niches have negative mitigation costs (−14.30, −10.68, −0.98) USD/tCO2e, mainly due to the high savings in the cost of fossil fuels and their materialization, especially for the mezcal niche which has a mitigation potential of 2.97 MtCO2e, requires only an adequate regulatory and normative framework. We conclude that using commercial SBFs (pellets, briquettes, and traditional firewood) in SMEs niches contribute to generating formal markets with adequate distribution channels, both for SBFs and sustainable residual biomass inputs (residual firewood, agave bagasse, and spent barley grain). This alternative scenario also promotes the creation of green jobs in agricultural and forestry areas, adding an economic value to residual biomass inputs not previously considered and contributing to the social development of rural areas.

Potential for the Integrated Production of Biojet Fuel in Swedish Plant Infrastructures

Replacing fossil jet fuel with biojet fuel is an important step towards reducing greenhouse gas (GHG) emissions from aviation. To this end, Sweden has adopted a GHG mandate on jet fuel, complementing those on petrol and diesel. The GHG mandate on jet fuel requires a gradual reduction in the fuel’s GHG emissions to up to 27% by 2030. This paper estimates the potential production of biojet fuel in Sweden for six integrated production pathways and analyzes what they entail with regard to net biomass input and the amount of hydrogen required for upgrading to fuel quality. Integrated production of biofuel intermediates from forestry residues and by-products at combined heat and power plants as well as at the forest industry, followed by upgrading to biojet fuel and other transportation fuels at a petroleum refinery, was assumed in all the pathways. The potential output of bio-based transportation fuels was estimated to 90 PJ/y, including 22 PJ/y of biojet fuel. The results indicate that it will be possible to meet the Swedish GHG mandate for jet fuel for 2030, although it will be difficult to simultaneously achieve the GHG mandates for road transportation fuels. This highlights the importance of pursuing complementary strategies for bio-based fuels.

Obtaining Cellulose-Available Raw Materials by Pretreatment of Common Agro-Forestry Residues With Pleurotus spp.

The goals of the present study were to characterize the profile of ligninolytic enzymes in five Pleurotus species and determine their ability to delignify eight common agro-forestry residues. Generally, corn stalks were the optimal inducer of Mn-dependent peroxidase activity, but the activity peak was noted after wheat straw fermentation by P. eryngii (3066.92 U/L). P. florida was the best producer of versatile peroxidase, especially on wheat straw (3028.41 U/L), while apple sawdust induced the highest level of laccase activity in P. ostreatus (49601.82 U/L). Efficiency of the studied enzymes was expressed in terms of substrate dry matter loss, which was more substrate-than species-dependent. Reduction of substrate dry mass ranged between 24.83% in wheat straw and 8.83% in plum sawdust as a result of fermentation with P. florida and P. pulmonarius, respectively. The extent of delignification of the studied substrates was different, ranging from 51.97% after wheat straw fermentation by P. pulmonarius to 4.18% in grapevine sawdust fermented by P. ostreatus. P. pulmonarius was also characterized by the highest cellulose enrichment (6.54) and P. ostreatus by very low one (1.55). The tested biomass is a highly abundant but underutilized source of numerous value-added products, and a cocktail of ligninolytic enzymes of Pleurotus spp. could be useful for its environmentally and economically friendly transformation.

Laccase activity from Pleurotus ostreatus and Flammulina velutipes strains grown on agro- and forestry residues by solid-state fermentation

Laccase activity from Pleurotus ostreatus and Flammulina velutipes strains was investigated with various agro- and forestry residues by solid-state fermentation. Different species or strains belonging to the same species had the unique capacity of secreting laccase on solid-state fermentation with various agro- and forestry residues. Overall, the capacity of secreting laccase for P. ostreatus strains was superior to F. velutipes strains due to the value of maximum activity on various agro- and forestry residues, except on the stalk of straw. Compared with Populus beijingensis, corncob, and stalk of straw, the presence of cottonseed hull was helpful to improve laccase activity for P. ostreatus strains because the maximum laccase activity from cottonseed hull was higher than that from the other three agro- and forestry residues. The presence of stalk of straw was more helpful to improve laccase activity for F. velutipes strains because of the maximum laccase activity from stalk of straw was higher that from Populus beijingensis, corncob, and cottonseed hull. These results indicated the importance of selecting suitable agro- and forestry residues for fungi producing laccase. These findings contributed to the selection of suitable strains to obtain an integrated application of low-cost laccase in the factory.

AGRO-FORESTRY RESIDUES VALORIZATION BY LIGNINOSOME OF GRIFOLA FRONDOSA

Grifola frondosa HAI 1232 was tested for ligninolytic enzyme activities and for lignin, cellulose and hemicellulose degradation during cultivation on eight common agro-forestry residues in Serbia. Wheat straw was favorable lignocellulosic for the production of Mn-dependent and Mn-independent peroxidases (2513.89 and 354.17 U L-1, respectively), while selected residues inhibited the synthesis of laccases. The highest lignin removal was observed during fermentation of blackberry sawdust (36.75%), while the highest selectivity index was recorded on oak sawdust (4.34). The dry matter loss varied between 8.17% in corn stalks and 14.16% in apple sawdust. According to the presented results, it can be concluded that G. frondosa HAI 1232 could be an important participant in various biotechnological processesdue to its high capacity to selectively degrade different agro-forestry residues.

Advanced materials design based on waste wood and bark

Trees belong to the largest living organisms on Earth and plants in general are one of our main renewable resources. Wood as a material has been used since the beginning of humankind. Today, forestry still provides raw materials for a variety of applications, for example in the building industry, in paper manufacturing and for various wood products. However, many parts of the tree, such as reaction wood, branches and bark are often discarded as forestry residues and waste wood, used as additives in composite materials or burned for energy production. More advanced uses of bark include the extraction of chemical substances for glues, food additives or healthcare, as well as the transformation to advanced carbon materials. Here, we argue that a proper understanding of the internal fibrous structure and the resulting mechanical behaviour of these forest residues allows for the design of materials with greatly varying properties and applications. We show that simple and cheap treatments can give tree bark a leather-like appearance that can be used for the construction of shelters and even the fabrication of woven textiles. This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 1)’.

Analysis of the EU Secondary Biomass Availability and Conversion Processes to Produce Advanced Biofuels: Use of Existing Databases for Assessing a Metric Evaluation for the 2025 Perspective

Nowadays in Europe, the production of advanced biofuels represents a very important objective, given the strong interest in increasing sustainability throughout the transport sector. Production and availability of advanced biofuels are cited as a relevant issue in the most important international actions, such as the Sustainable Development Goals in UN Agenda 2030, EU RED II, and EU Mission Innovation 4, to cite a few of them. However, an important aspect to be considered is the prediction of feedstocks availability to produce advanced biofuel. The first aim of this paper is to assess the availability of European agricultural residues, forestry residues, and biogenic wastes in 2025. The data were collected through a deep review on open FAOSTAT and EUROSTAT databases and then elaborated by the authors. The analysis focuses on the fraction of feedstocks that can be used for advanced biofuels production, i.e., incorporating specific information on sustainable management practices, competitive uses, and environmental risks to preserve soil quality. An autoregressive model is developed to predict future availability, while also considering corrections due to the current pandemic. The results suggest that several European countries could produce enough sustainable advanced feedstocks to meet the European binding target. In particular, France, Germany, and Romania will have high production of agricultural feedstocks; while Austria, Finland, and Sweden will be rich of forestry residues; finally, Italy, France, and United Kingdom will have the highest availability of wastes. To complete the picture, a proper metric is introduced, aiming at generating a technology ranking of the examined alternative fuels, in terms of several relevant parameters such as biomass availability, Technology Readiness Level (TRL), quality of the biofuel, and costs. This analysis allows us to compare advanced biofuels and first-generation biofuels, whose utilization can impact the food market, while also contributing to the increase in the indirect land use change (ILUC). Although the first-generation biofuels remain the most common choice, the renewable (or green) diesel, pyrolysis bio-oil, green jet fuel, and the second-generation bioethanol are promising for different applications in the transport sector. Hydrotreated Vegetable Oils (HVO), Hydroprocessed Esters and Fatty Acids (HEFA), Anaerobic Digestion (AD), and transesterification from vegetable oil represent the most widespread and mature technologies. Thus, it seems mandatory that the transport sector will rely more and more on such fuels in the future. For such reason, a specific support for advanced biomass collection, as well as specific programs for conversion technologies development, are strongly suggested.