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The yeast Yarrowia lipolytica is an industrially relevant microorganism, which is able to convert low-value wastes into different high-value, bio-based products, such as enzymes, lipids, and other important metabolites. Waste cooking oil (WCO) represents one of the main streams generated in the food supply chain, especially from the domestic sector. The need to avoid its incorrect disposal makes this waste a resource for developing bioprocesses in the perspective of a circular bioeconomy. To this end, the strain Y. lipolytica W29 was used as a platform for the simultaneous production of intracellular lipids and extracellular lipases. Three different minimal media conditions with different pH controls were utilized in a small-scale (50 mL final volume) screening strategy, and the best condition was tested for an up-scaling procedure in higher volumes (800 mL) by selecting the best-performing possibility. The tested media were constituted by YNB media with high nitrogen restriction (1 g L−1 (NH4)2SO4) and different carbon sources (3% w v−1 glucose and 10% v v−1 WCO) with different levels of pH controls. Lipase production and SCO content were analyzed. A direct correlation was found between decreasing FFA availability in the media and increasing SCO levels and lipase activity. The simultaneous production of extracellular lipase (1.164 ± 0.025 U mL−1) and intracellular single-cell oil accumulation by Y. lipolytica W29 growing on WCO demonstrates the potential and the industrial relevance of this biorefinery model.

Energy and environmental effects of wheat-based fuel, produced continuously by a Blenke cascade system, were assessed. Two scenarios: (1) no-co-products utilization scenario; and (2) co-products utilization scenario, were compared. A Life Cycle Assessment (LCA) model was used for analysis. The scope covered a cradle-to-gate inventory. The results from energy analysis showed, that wheat-based ethanol has a positive average net energy value (NEV), NEV = 3.35 MJ/kg ethanol with an average net energy ratio (NER), NER = 1.14 MJ/MJ fossils for scenario 1, while for scenario 2, NEV = 20 MJ/kg ethanol with NER = 3.94 MJ/MJ fossils. The environmental performance analysis indicated that in scenario 1, the strongest contribution to environmental impacts was from the ethanol conversion stage; whereas in scenario 2, it was from wheat production stage. The use of a continuous fermentation system based on Blenke cascade is a promising technology that increases wheat based bio-ethanol’s energy benefits. In addition, the calculated parameters show the potential to significantly reduce emissions level.

Marginal farm land is land characterised by low food, feed and fodder crop productivity due to soil and environmental limitations. Such land may however be utilised for bio-energy crop production. We investigate the economic viability of small scale combined heat and power anaerobic digestion (CHP AD) projects based on feedstock from farm waste and bio-energy crops grown on a representative temperate latitude marginal farm land in the UK. Using a realistic set of five project feedstock-mix scenarios, and considering standard technology and current market and policy regimes, we deploy a stochastic framework to assess prices of electricity required for these projects to break-even and conduct sensitivity analyses of key project parameters. Accounting for the current market prices and policy tariffs for heat, we find that critical electricity sale prices of about 17.46 p/kWh to 27.12 p/kWh are needed for the projects to break even. These prices are well above the current combined feed-in-tariff support and market prices for electricity over the past years in the UK. We conclude that the use of marginal land to generate power for export using small-scale CHP AD in the UK and the wider temperate latitude countries is unviable, if energy and farming policy regimes do not provide substantial support.

Bioenergy represents the highest share of renewable energies consumed in the European Union and is still expected to grow. This could be possible by exploring bioenergy production on Marginal, Underutilised, and Contaminated lands (MUC) that are not used for agricultural purposes and therefore, present no competition with food/feed production. In this paper, the viability and sustainability of bioenergy value chains on these lands is investigated and measures for market uptake were developed. Using three case study areas in Italy, Ukraine, and Germany, a screening of MUC lands was conducted, then an agronomic assessment was performed to determine the most promising crops. Then, techno-economic assessments followed by sustainability assessments were performed on selected value chains. This concept was then automated and expanded through the development of a webGIS tool. The tool is an online platform that allows users to locate MUC lands in Europe, to define a value chain through the selection of bioenergy crops and pathways, and to conduct sustainability assessments measuring a set of environmental, social, and economic sustainability indicators. The findings showed positive results in terms of profitability and greenhouse gas emissions for bioethanol production from willow in Ukraine, heat and power production from miscanthus, and biogas and chemicals production from grass in Germany. The webGIS tool is considered an important decision-making tool for stakeholders, which gives first insights on the viability and sustainability of bioenergy value chains.

The article provides an overview of various studies on energy consumption in agriculture. The focus was in particular on the sensitivity of farms and agribusiness to fluctuations in the prices of energy carriers, which is currently a problem for the entire food industry. In addition to the prices of direct energy carriers, biofuels, the EU ETS system, and fertilizers were identified as the main areas that play a key role in shaping the direct and indirect impact on the economic performance of agricultural producers. Moreover, it was presented how sensitive the food sector is to the limitations of fertilizer production, during which by-products necessary in food processing are produced. The production of fertilizers consumes almost half of the energy used in agriculture, but the lack of fertilizers means yield drops of 30–50%. Therefore, high energy prices and disruptions in its supply are a threat to the food security of a country, both from the perspective of agriculture and processing. Based on the literature review, research gaps have been identified that should guide future research.

Studies on the use of biomass from short rotation coppices for briquette production as a sustainable biofuel have been scarce in the literature. This study investigated the effects of two process variables, hammer mill screen size at three levels (5.3, 10.3, and 25.4 mm) and moisture content at three levels (13.6, 19, and 25% (w.b.)), on the properties of briquettes from poplar Max-4 trees. The whole tree was divided into two fractions, the crown and the stem, and briquettes were produced from them. The effects of the variables on compressed density, relaxed density, relaxation ratio, and the shatter index of the briquettes were analyzed. The results showed that the combined interaction of the variables had no significant effects (p > 0.05) on the compressed density, relaxed density, and relaxation ratio of the briquettes. However, hammer mill screen size and moisture content both significantly influenced the shatter index irrespective of the tree fraction (p < 0.05). Hammer mill screen sizes of 5.3 and 10.3 mm at moisture contents of 13.6 and 19% (w.b.) resulted in good quality briquettes across the properties investigated for both the crown and stem poplar tree fractions. This study shows that high-quality briquettes can be produced from poplar Max-4 woody biomass.

A number of measures to diversify its energy supply sources and reduce its dependence on imported energy sources has been taken by the EU. These include pursuing new energy sources, such as renewable energy and liquefied natural gas; increasing the storage capacities; and investing in interconnectors and other infrastructure. However, these actions require long-term adjustment, while there is a need to find an option to meet the energy needs at a moment. One possible option is to utilize seed production wastes for energy production. This research paper aims to investigate the potential of utilizing seed production wastes (SPWs) for energy production in continental Croatia, and assess its feasibility. Eight different SPWs were used in this research, where their energy characteristics were determined and the theoretical thermal potential was calculated if they are used as raw material in the production of thermal energy through biomass and cogeneration power plants, or in biogas power plants. By using the available feedstock, it is theoretically possible to produce a total of 38,051.10 GJ of thermal energy by direct combustion of SPWs and 34,727.91 GJ by combustion of the produced biomethane. The SPWs of oilseed rape and beans contain the highest specific heat potential per hectare.

Pruning residues could represent an important biomass resources for energy production. Only in Italy it has been estimated that an annual quantity of biomass of over 2600 kt of dry matter could be obtained from olive residues. Several machines developed for pruning harvesting are available in the market, most of which are tractor-driven, while limited knowledge is available on performance, quality of work and costs of harvesting logistics based on stationary chippers. The aim of the present paper is to analyze machine performance of a forestry stationary chipper applied to pruning harvesting for what concerns work productivity, quality of the comminuted product and harvesting operating costs. This system is actually applied by Fiusis Company, an Italian enterprise which manages a biomass power plant exclusively powered by olive trees’ pruning residues, and it has never been analyzed in literature. The results obtained showed consistent work productivity, which resulted the highest ever found in olive pruning harvesting systems and equal to 5.23 ± 0.81 tdm·h−1. This high work productivity allowed also to obtain a little economic gain from a matter, which is actually considered a problem for olive groves’ owners and not a potential source of income. In particular, the use of a stationary chipper seemed very efficient in olive groves with a consistent amount of wooden residues to be processed and with big branches not harvestable by the most common towed pruning harvester. In addition, the stationary chipper has the advantage of avoiding the preliminary raking operation, which results in reduced costs for the farmer.