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Integration of anaerobic digestion (AD) with microalgae processes has become a key topic to support economic and environmental development of this resource. Compared with other substrates, microalgae can be produced close to the plant without the need for arable lands and be fully integrated within a biorefinery. As a limiting step, anaerobic hydrolysis appears to be one of the most challenging steps to reach a positive economic balance and to completely exploit the potential of microalgae for biogas and fertilizers production. This review covers recent investigations dealing with microalgae AD and highlights research opportunities and needs to support the development of this resource. Novel approaches to increase hydrolysis rate, the importance of the reactor design and the noteworthiness of the microbial anaerobic community are addressed. Finally, the integration of AD with microalgae processes and the potential of the carboxylate platform for chemicals and biofuels production are reviewed.

Abstract. Bookkeeping models are used to estimate land-use and land-cover change (LULCC) carbon fluxes (ELULCC). The uncertainty of bookkeeping models partly arises from data used to define response curves (usually from local data) and their representativeness for application to large regions. Here, we compare biomass recovery curves derived from a recent synthesis of secondary forest plots in Latin America by Poorter et al. (2016) with the curves used previously in bookkeeping models from Houghton (1999) and Hansis et al. (2015). We find that the two latter models overestimate the long-term (100 years) vegetation carbon density of secondary forest by about 25 %. We also use idealized LULCC scenarios combined with these three different response curves to demonstrate the importance of considering gross forest area changes instead of net forest area changes for estimating regional ELULCC. In the illustrative case of a net gain in forest area composed of a large gross loss and a large gross gain occurring during a single year, the initial gross loss has an important legacy effect on ELULCC so that the system can be a net source of CO2 to the atmosphere long after the initial forest area change. We show the existence of critical values of the ratio of gross area change over net area change (γAnetAgross), above which cumulative ELULCC is a net CO2 source rather than a sink for a given time horizon after the initial perturbation. These theoretical critical ratio values derived from simulations of a bookkeeping model are compared with observations from the 30 m resolution Landsat Thematic Mapper data of gross and net forest area change in the Amazon. This allows us to diagnose areas in which current forest gains with a large land turnover will still result in LULCC carbon emissions in 20, 50 and 100 years.

The influence of green waste, biowaste and paper-cardboard proportions in initial mixtures on organic matter (OM) evolution during composting in pilot-scale reactors was studied using respirometric procedure, humic substance extraction, crude fiber analysis and Fourier transform infrared spectroscopy. The stabilisation of OM during composting resulted from the degradation of easily biodegradable organic fraction as cellulose and hemicellulose, the relative increase of resistant compounds as lignin, the microbial synthesis of resistant biomolecules, and from humification processes. Little stabilisation of green waste OM during composting was observed, in relation with their large lignin content. With moderate contents of paper-cardboard in initial mixtures (20-40%), cellulose proportion remained favorable to fast OM stabilisation. Larger proportions of paper-cardboard (more than 50%) affected OM stabilisation, probably due to a lack of nitrogen. The influence of biowastes only appeared at the very beginning of composting, because of their large proportions of easily biodegradable OM.

Nowadays, industrial enterprises are facing up to new challenges to well optimize their performances, with regards not only to conventional performances (e.g. reliability or productivity) but also to emerging ones as those related to sustainability issues. Indeed, sustainability indicators have to be considered now in the decision-making process of the plant to better control and maintain it to be consistent with Green Production requirements. In that way, indicators such as Energy Efficiency or Energy Consumption are promoted for the impact they have on these requirements in a Life Cycle Cost vision. Thus the core idea defended in this paper is addressing the necessary evolution of conventional maintenance decision-making process in industry for considering the energy efficiency indicator. To support the idea, the first objective is to define the concept of energy efficiency indicator which materializes the energy efficiency performance at a specific time. The definition is done for different abstraction levels such as component, function, system which are subjected to time-dependent degradation behaviors. So, the energy efficiency indicator concept is expressed as the amount of energy consumed per unit of useful output, which has to be seen as a sustainable performance measure of industrial system. Then a mathematical formulation is proposed to calculate energy efficiency indicator at any time of the performance by considering dependent factors (static and dynamic ones) impacting inputs and outputs of the system. The second objective is to propose a new concept named REEL (Remaining energy-efficient lifetime) for tracking the energy efficiency performance evolution. The REEL is defined by the time left before the system loses its energy efficiency property considered as a specific EEI value (EEI threshold) not to be exceeded. This specific value is technically and/or economically fixed in advance, given the current condition, past and future operation profiles. The REEL could be used as an appropriate indicator for maintenance decision-making process in a proactive vision. The third objective is to formalize a generic approach in the way assess the REEL value. The assessment requires to forecast the evolution of energy efficiency indicator (whatever the abstraction level is) by taking into account the static and dynamic factors. Finally, the feasibility and added value of our proposals are illustrated on a manufacturing platform named TELMA (TELeMAintenance).

AbstractRice is the most important food crop in the developing world. For rice production systems to address the challenges of increasing demand and climate change, potential and on‐farm yield increases must be increased. Breeding is one of the main strategies toward such aim. Here, we hypothesize that climatic and atmospheric changes for the upland rice growing period in central Brazil are likely to alter environment groupings and drought stress patterns by 2050, leading to changing breeding targets during the 21st century. As a result of changes in drought stress frequency and intensity, we found reductions in productivity in the range of 200–600 kg/ha (up to 20%) and reductions in yield stability throughout virtually the entire upland rice growing area (except for the southeast). In the face of these changes, our crop simulation analysis suggests that the current strategy of the breeding program, which aims at achieving wide adaptation, should be adjusted. Based on the results for current and future climates, a weighted selection strategy for the three environmental groups that characterize the region is suggested. For the highly favorable environment (HFE, 36%–41% growing area, depending on RCP), selection should be done under both stress‐free and terminal stress conditions; for the favorable environment (FE, 27%–40%), selection should aim at testing under reproductive and terminal stress, and for the least favorable environment (LFE, 23%–27%), selection should be conducted for response to reproductive stress only and for the joint occurrence of reproductive and terminal stress. Even though there are differences in timing, it is noteworthy that stress levels are similar across environments, with 40%–60% of crop water demand unsatisfied. Efficient crop improvement targeted toward adaptive traits for drought tolerance will enhance upland rice crop system resilience under climate change.