• Energy Research

Abstract Agro-ecosystems have large potentials for supporting human well-being and local development, also by providing large amounts of organic matter for bioenergy generation. The use of agricultural residues was proposed as a possible solution to support energy transition, while avoiding conflicts for the use of agricultural land destined to food production. The present work uses an Ecosystem Services (ES) approach to map and estimate the potential availability of agricultural residues (potential ES supply) in the Emilia-Romagna region (Italy), where high productive croplands are present. The map was overlapped with the bioenergy plants currently present in the region (ES demand) that could be sustained by residues, considering a buffer area of 10 km radius for a sustainable supply chain and under the assumption of using only the 25% of total residues. Additionally, suitable areas for bioenergy development were mapped by means of a hotspot analysis. The results showed that the Emilia-Romagna region has a large availability of agricultural residues to be potentially used for bioenergy generation. The 82.4% of the total installed power of biogas plants and the whole installed power of those using woody biomasses may be supported by using agricultural residues. When considering buffer areas for sustainable supply chains, agricultural residues could meet the 95% and 50% of total demand from biogas and solid biomasses plants, respectively. However, competition for agricultural residues among bioenergy plants could arise because of the overlap of their buffer zones. Moreover, hotspot analysis revealed large suitable areas for the development of environmental and cost-effective biogas plants. Contrasting ES supply and demand may unveil unexplored forms of sustainable development in agro-ecosystems, thus contributing to a more rational use of agricultural production which supports renewable energies without competing for the agricultural land.

Bioenergies are considered sustainable alternatives to fossil energy sources in the European Union (EU) renewable energy targets for 2030. However, their performances in terms of greenhouse gases (GHG) savings may be affected by indirect emissions related to the required land-use-change (LUC) that should be taken into account when modelling their sustainability. The European Renewable Energy Directive (RED) introduced a number of GHG emission criteria, in comparison with fossil fuels, that bioenergy deriving from agricultural biomasses must comply with. The Emilia-Romagna region (North-Eastern Italy), the second largest Italian biogas producer, has recently issued its Regional Energy Plan (REP), which set an ambitious increase of about 40% of the current installed electric power from biogas up to 2030. The aim of this study is to assess the sustainability of Emilia-Romagna REP accounting for the required indirect land-use-change (ILUC), due to the bioenergy crop expansion, potentially needed to reach the targets. Based on regional data available on biogas production, the amount of land used for maize silage to be destined to biogas production (as a model agricultural feedstock) has been calculated for the actual state-of-the art and towards 2030 scenarios provided by the REP. Starting from average GHG emissions associated with biogas production from 100% maize silage of 35 gCO2 eq/MJ, a further contribution of 8–18.5 gCO2 eq/MJ due to LUC has been found. Our findings indicate that it is difficult to assess the global GHG savings from the bioenergy targets fixed by regional energy plans when LUC effects are considered. Careful analysis is necessary in each case to avoid creating negative impacts.

Near-infrared (NIR) spectroscopy has been developed as a noninvasive tool for the direct, real-time monitoring of glucose, lactic acid, acetic acid, and biomass in liquid cultures of microrganisms of the genera Lactobacillus and Staphylococcus. This was achieved employing a steam-sterilizable optical-fiber probe immersed in the culture (In-line Interactance System®). Second-derivative spectra obtained were subjected to partial least-squares (PLS) regression and the results were used to build predictive models for each analyte of interest. Multivariate regression was carried out on two different sets of spectra, namely whole broth minus the spectral subtraction of water, and raw spectra. A comparison of the two models showed that the first cannot be properly applied to real-time monitoring, so this work suggests calibration based on non-difference spectra, demonstrating it to be sufficiently reliable to allow the selective determination of the analytes with satisfactory levels of prediction (standard error of prediction (SEP) < 10%). Direct interfacing of the NIR system to the bioreactor control system allowed the implementation of completely automated monitoring of different cultivation strategies (continuous, repeated batch). The validity of the in-line analyses carried out was found to depend crucially on maintaining constant hydrodynamic conditions of the stirred cultures because both gas flow and stirring speed variations were found to markedly influence the spectral signal.

The need to reduce the environmental impacts of the food industry is increasing together with the dramatic increment of global food demand. Circulation strategies such as the exploitation of self-produced renewable energy sources can improve ecological performances of industrial processes. However, evidence is needed to demonstrate and characterize such environmental benefits. This study assessed the environmental performances of industrial processing of maize edible oil, whose energy provision is guaranteed by residues biomasses. A gate-to-gate Life Cycle Assessment (LCA) approach was applied for a large-size factory of Northern Italy to describe: (i) the environmental impacts related to industrial processing and (ii) the contribution of residue-based bioenergy to their mitigation, through the comparison with a reference system based on conventional energy. The results showed that oil refinement is the most impacting phase for almost all the considered impact categories. The use of residue-based bioenergy was found to drastically reduce the emissions for all the impact categories. Moreover, Cumulative Energy Demand analysis revealed that the use of biomass residues increased energy efficiency through a reduction of the total energy demand of the industrial process. The study demonstrates that the exploitation of residue-based bioenergy can be a sustainable solution to improve environmental performances of the food industry, while supporting circular economy.

In recent years, there has been an increasing interest in Life Cycle Assessment (LCA) applied to estimate the cradle-to-grave environmental impact of agricultural products or processes. Furthermore, including in the analysis an economic evaluation, from the perspective of an integrated life cycle approach, appears nowadays as a fundamental improvement. In particular, Life Cycle Costing (LCC), is a method that could integrate financial data and cost information with metrics of life cycle approaches. In this study, LCA in conjunction with LCC methods were used, with the aim to evaluate the main cost drivers—environmental and economic—of five widely diffused and market-valued agricultural productions (organic tomato and pear, integrated wheat, apple and chicory) and to combine the results in order to understand the long-term externalities impacts of agricultural productions. Data obtained in local assessment show a wide margin of improvement of resources management at farms level in the short-term, but also allow for the investigation of future effects of environmental impacts not expressed in product price on the market. Reaching a real sustainable model for agriculture could be a value added approach firstly for farmers, but also for all the people who live in rural areas or use agricultural products.

The utilization of mono-, di-, and oligosaccharides by Bifidobacterium adolescentis MB 239 was investigated. Raffinose, fructooligosaccharides (FOS), lactose, and the monomeric moieties glucose and fructose were used. To establish a hierarchy of sugars preference, the kinetics of growth and sugar consumption were determined on individual and mixed carbohydrates. On single carbon sources, higher specific growth rates and cell yields were attained on di- and oligosaccharides compared to monosaccharides. Analysis of the carbohydrates in steady-state chemostat cultures, growing at the same dilution rate on FOS, lactose, or raffinose, showed that monomeric units and hydrolysis products were present. In chemostat cultures on individual carbohydrates, B. adolescentis MB 239 simultaneously displayed alpha-galactosidase, beta-galactosidase, and beta-fructofuranosidase activities on all the sugars, including monosaccharides. Glycosyl hydrolytic activities were found in cytosol, cell surface, and growth medium. Batch experiments on mixtures of carbohydrates showed that they were co-metabolized by B. adolescentis MB 239, even if different disappearance kinetics were registered. When mono-, di-, and oligosaccharides were simultaneously present in the medium, no precedence for monosaccharides utilization was observed, and di- and oligosaccharides were consumed before their constitutive moieties.

Agro-ecosystems are intensively exploited environments which are both providers and consumers of ecosystem services. The improvement of both provisioning and regulating services in cultivated landscapes is crucial for the sustainable development of rural areas. Among the provisioning services offered, producing biogas from the anaerobic digestion of residual biomass is nowadays a promising option for decreasing greenhouse gas (GHG) emissions, while avoiding the land use conflicts related to the use of dedicated crops. Based on the available quantitative data at a regional level, provisioning and regulating services provided by the use of agri-food waste, livestock waste and agricultural residues were assessed for the case of Emilia Romagna region, the second biggest biogas producer in Italy. One provisioning service, i.e., bioenergy generation, and three regulating services were considered: (i) air quality improvement by the reduction of odors derived from direct use of waste, (ii) regulation of soil nutrients by reducing organic load and digestate spreading, and (iii) global climate regulation by saving GHG emissions. A potential further generation of 52.7 MW electric power was estimated at the regional level. Digestate spreading on fields may reduce odor impact by more than 90%, while containing a higher percentage of inorganic nitrogen, which is readily available to plants. The estimated GHG emission savings were equal to 2,862,533 Mg CO2eq/yr, mainly due to avoided landfilling for agri-waste and avoided replacing of mineral fertilizers for livestock waste and agricultural residues. The results suggest that bioenergy generation from lignocellulosic, livestock and agro-industrial residues may improve some regulating services in agro-ecosystems, while helping to reach renewable energy targets, thus contributing to overcoming the provisioning vs. regulating services paradigm in human-managed ecosystems.

Environmental problems in the traditional beet sugar processing are mainly related to the production of large amounts of pulp, the consumption of large quantities of lime (which are transformed into sludges), the production of vinasse, and the consumption of energy and water. It is proposed:– To utilize the pulp and carbonation sludge for the production of paper; – To utilize vinasse for the production of compost; – To utilize new technologies for eliminating the utilization of lime; – To apply the “Water Pinch” and “Pinch Analysis” to the new technologies for drastically reducing both the water and the energy consumption.