Identification et caractérisation des déchets organiques au Maroc, une étape importante dans la valorisation des déchets

The introduction of new valorization and bioconversion techniques of organic waste in Morocco is a lever for a promising bio-economy able to exploit all available resources of the country including waste. The success of these techniques is first conditioned by the perfect knowledge of the characteristics of the available biomass potential. Thus, this research is particularly interested in the identification and characterization of organic waste at the national level for eventual bioconversion to other products with added value such as bioethanol, lactic acid, amino acids, proteins and fertilizers. The identification of these biological materials has been established by making a state-of-the-art on different researches, studies and statistics to estimate the potential volume at the national level and especially those generated by agriculture and agrifood industry. The determination of the chemical composition of biomass was carried for the nine most important biomaterials in the country in terms of quantitative and qualitative potential. After evaluating the various production sectors, it has been estimated global potential of organic waste at approximately 60 million tons produced annually across Morocco, with 92% of agricultural wastes. A share of this biomass is currently marketed as inputs in the agricultural sector;while other residues have no economic value and are disposed of to landfill or incineration. The results of chemical characterization of the 9 samples studied have identified two types of biomass: sugar based feedstock and nutrient based feedstock including the estimated yield for bioethanol, biogas, lactic acid and fertilizer. These results show that organic wastes available in Morocco are well adapted to transformation process to produce value added bio-based products. Keywords: Organic waste, valorization, bioconversion, environmental impact, energy, bio-economy, MoroccoL’introduction de nouvelles techniques de valorisation et de bioconversion de déchets organiques au Maroc est un levier pour une bio-économie prometteuse en mesure d’exploiter toutes les ressources disponibles du pays y compris les déchets. Le succès de ces techniques est d’abord conditionnée par la parfaite connaissance des caractéristiques du potentiel de la biomasse disponible. Ainsi, cette recherche s’est particulièrement intéressée à l’identification et à la caractérisation des déchets organiques à l’échelle nationale pour bioconversion éventuelle à d’autres produits à valeur ajoutée tels que le bioéthanol, l’acide lactique, des acides aminés, les protéines et les engrais. L’identification de ces matériaux biologiques a été mise en place en faisant un état de l’art sur les différentes recherches, études et statistiques pour estimer le volume potentiel au niveau national et en particulier ceux générés par l’industrie agro-alimentaire et l’agriculture. La détermination de la composition chimique de la biomasse a été effectuée pour les neuf biomatériaux les plus importants du pays en termes de potentiel quantitatif et qualitatif. Après avoir évalué les différents secteurs de production, il a été estimé qu’un potentiel global des déchets organiques est de l’ordre de 60 millions de tonnes produites chaque année à travers le Maroc, avec 92% des déchets agricoles. Une part de cette biomasse est actuellement commercialisée comme intrants dans le secteur agricole, tandis que d’autres résidus n’ont aucune valeur économique et sont mis en décharge ou incinérés. Les résultats de la caractérisation chimique des 9 échantillons étudiés ont identifié deux types de biomasse: matières premières à base de sucre et celles à base et d’éléments nutritifs y compris le rendement estimé pour le bioéthanol, le biogaz, l’acide lactique et l’engrais. Ces résultats montrent que les déchets organiques disponibles au Maroc sont bien adaptés aux processus de transformation pour produire des produits à haute valeur ajoutée. Mots-clés: Déchets organiques, valorisation, bioconversion, impact sur l’environnement, énergie, bio-économie, Maro

Butanol fermentation of the brown seaweed Laminaria digitata by Clostridium beijerinckii DSM-6422

Seaweed represents an abundant, renewable, and fast-growing biomass resource for 3rd generation biofuel production. This study reports an efficient butanol fermentation process carried out by Clostridium beijerinckii DSM-6422 using enzymatic hydrolysate of the sugar-rich brown seaweed Laminaria digitata harvested from the coast of the Danish North Sea as substrate. The highest butanol yield (0.42 g/gconsumed-substrates) compared to literature was achieved, with a significantly higher butanol: acetone-butanol-ethanol (ABE) molar ratio (0.85) than typical (0.6). This demonstrates the possibility of using the seaweed L. digitata as a potential biomass for butanol production. For the first time, consumption of alginate components was observed by C. beijerinckii DSM-6422. The efficient utilization of sugars and lactic acid further highlighted the potential of using this strain for future development of large-scale cost-effective butanol production based on (ensiled) seaweed

Crude fucoidan content in two North Atlantic kelp species, Saccharina latissima and Laminaria digitata - seasonal variation and impact of environmental factors

Fucoidans are sulphated fucose-rich polysaccharides predominantly found in the cell walls of brown algae. The bioactive properties of fucoidans attract increasing interest from the medico-pharmaceutical industries and may drive an increase in demand of brown algae biomass. In nature, the biochemical composition of brown algae displays a seasonal fluctuation driven by environmental factors and endogenous rhythms. To cultivate and harvest kelps with high yields of fucoidans, knowledge is needed on seasonal variation and impact of environmental conditions on the fucoidan content of brown algae. The relations between the fucoidan content and key environmental factors (irradiance, nutrient availability, salinity and exposure) were examined by sampling natural populations of the common North Atlantic kelps, Saccharina latissima and Laminaria digitata, over a full year at Hanstholm in the North Sea and Aarhus in the Kattegat. In addition, laboratory experiments were carried out isolating the effects of the single factors. The results demonstrated that (1) seasonal variation alters the fucoidan content by a factor of 2–2.6; (2) interspecific differences exist in the concentrations of crude fucoidan (% of dry matter): L. digitata (11%) > S. latissima (6%); and (3) the effects of single environmental factors were not consistent between species or between different conspecific populations. The ambiguous response to single environmental factors complicates prospective directions for manipulating an increased content of fucoidan in a cultivation scenario and emphasizes the need for knowledge on performance of local kelp ecotypes.This study was carried out as part of the MacroAlgae Biorefinery (MAB3), the MacroAlgae Biorefinery 4 (MAB4) and the Macrofuels projects, funded by The Danish Council for Strategic Research, the Innovation Fund Denmark and the European Union's Horizon 2020 research and innovation programme under grant agreement no. 654010, respectively

Household, community, sub-national and country-level predictors of primary cooking fuel switching in nine countries from the PURE study

Introduction. Switchingfrom polluting (e.g. wood, crop waste, coal)to clean (e.g. gas, electricity) cooking fuels can reduce household air pollution exposures and climate-forcing emissions.While studies have evaluated specific interventions and assessed fuel-switching in repeated cross-sectional surveys, the role of different multilevel factors in household fuel switching, outside of interventions and across diverse community settings, is not well understood. Methods.We examined longitudinal survey data from 24 172 households in 177 rural communities across nine countries within the Prospective Urban and Rural Epidemiology study.We assessed household-level primary cooking fuel switching during a median of 10 years offollow up (∼2005–2015).We used hierarchical logistic regression models to examine the relative importance of household, community, sub-national and national-level factors contributing to primary fuel switching. Results. One-half of study households(12 369)reported changing their primary cookingfuels between baseline andfollow up surveys. Of these, 61% (7582) switchedfrom polluting (wood, dung, agricultural waste, charcoal, coal, kerosene)to clean (gas, electricity)fuels, 26% (3109)switched between different polluting fuels, 10% (1164)switched from clean to polluting fuels and 3% (522)switched between different clean fuels

Temperature-dependent Crystallization of MoS2 Nanoflakes on Graphene Nanosheets for Electrocatalysis

Abstract This work primarily studies the crystallization condition of molybdenum disulfide (MoS2) in MoS2/graphene hybrids by a temperature-varying hydrothermal method from 150 to 240 °C. Flower-like MoS2 nanoflakes were successfully grown on graphene nanosheets and characterized to understand the temperature-dependent crystallization process and the electrochemical performance. The highest electrocatalytic efficiency for both the dye-sensitized solar cell and the hydrogen evolution reaction was obtained by preparing the hybrid at 180 °C, which benefits from balanced high reactivity and high conductivity. This research leads to a better understanding of temperature dependence of MoS2 crystallization and offers guidelines for better catalytic material design. Graphical abstract Temperature-dependent Crystallization of MoS2 Nanoflakes on Graphene Nanosheets for Electrocatalysi

Identification and characterization of organic waste in Morocco, an important step towards the valorization of waste

The introduction of new valorization and bioconversion techniques of organic waste in Morocco is a lever for a promising bio-economy able to exploit all available resources of the country including waste. The success of these techniques is first conditioned by the perfect knowledge of the characteristics of the available biomass potential. Thus, this research is particularly interested in the identification and characterization of organic waste at the national level for eventual bioconversion to other products with added value such as bioethanol, lactic acid, amino acids, proteins and fertilizers. The identification of these biological materials has been established by making a state-of-the-art on different researches, studies and statistics to estimate the potential volume at the national level and especially those generated by agriculture and agrifood industry. The determination of the chemical composition of biomass was carried for the nine most important biomaterials in the country in terms of quantitative and qualitative potential. After evaluating the various production sectors, it has been estimated global potential of organic waste at approximately 60 million tons produced annually across Morocco, with 92% of agricultural wastes. A share of this biomass is currently marketed as inputs in the agricultural sector;while other residues have no economic value and are disposed of to landfill or incineration. The results of chemical characterization of the 9 samples studied have identified two types of biomass: sugar based feedstock and nutrient based feedstock including the estimated yield for bioethanol, biogas, lactic acid and fertilizer. These results show that organic wastes available in Morocco are well adapted to transformation process to produce value added bio-based products