To achieve sustainable energy crop production, energy crops should not compete for land against feed and food crops. One option for sustainable energy-crop cultivation is the use of double cropping systems with minimum tillage use and digestate as natural fertilizer, where, in the same growing season, a second crop for biomethane production is planted after a first crop used for feed/food. Different sorghum phenotypes were evaluated in the present study as first and second crops in a double cropping system. A principal component analysis of the various sorghum phenotypes showed that starch content positively affected methane production. However, sorghum chemical composition did not influence the profitability of bioenergy production as much as the total solid biomass yields of the different sorghum phenotypes. The highest total solid biomass productive sorghum phenotype led to the highest methane hectare yield.

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The bioelectrochemical systems are a sustainable technology that can be used to obtain electricity and/or reduced compounds. However, this novel technology presents several challenges prior to its implementation at full-scale. The aim of the present study was to evaluate different nanomaterials of electrode and mediators to increase the performance of BioElectrochemical Systems production. In order to achieve this objective, it was compared the use of Multiwall Carbon Nanotubes and Multiwall Carbon Nanotubes plus electron exogenous mediator (Meldola’s Blue) against plain graphite anode in order to evaluate the overall start-up time and other electro-chemical features. The use of multi-walled carbon nanotubes reduces substantially (by 75%) the start-up time required in a microbial fuel cell to produce stable voltage both, with and without the use of mediator compare to the plain anode. This reduction of the required time can be a consequence of the formation of anodic binders between this compound and the bacteria. With the independence of the start-up time, the current production was similar in the three studied cases, about 650 mV. Use of nanotubes modified anode surfaces might be especially interesting in cases of recovery after unstable operation of a microbial fuel cell, and/or reducing the start-up time for the generation of energy from new systems.

For sustainable biomethane production, energy crops should not compete for land against feed and food. In response to this requirement, a set of practices for an innovative way to produce food and biomethane was developed in Italy with the Biogasdoneright™ model, which introduces the double‐cropping system along with digestate fertilization and minimum tillage. Triticale is a promising feedstock as energy crop in such systems. Ninteen varieties of triticale harvested at milk and dough development stages were evaluated. Principal component analysis showed that cellulose content positively affects methane production whereas starch content has only a very weak relation with specific methane yield and methane formation rate. Despite these relations, triticale chemical composition did not influence the profitability of bioenergy production as much as the total biomass solids yields, the total solids concentration at harvest, and the timing of growth. Triticale can be considered a suitable energy crop for biomethane targeting at least 4600 Nm3 CH4 per hectare. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

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