BackgroundSugarcane distillery waste water (SDW) or vinasse is the residual liquid waste generated during sugarcane molasses fermentation and alcohol distillation. Worldwide, this effluent is responsible for serious environmental issues. In Reunion Island, between 100 and 200 thousand tons of SDW are produced each year by the three local distilleries. In this study, the potential of Aspergillus niger to reduce the pollution load of SDW and to produce interesting metabolites has been investigated.ResultsThe fungal biomass yield was 35 g L−1 corresponding to a yield of 0.47 g of biomass/g of vinasse without nutrient complementation. Analysis of sugar consumption indicated that mono-carbohydrates were initially released from residual polysaccharides and then gradually consumed until complete exhaustion. The high biomass yield likely arises from polysaccharides that are hydrolysed prior to be assimilated as monosaccharides and from organic acids and other complex compounds that provided additional C-sources for growth. Comparison of the size exclusion chromatography profiles of raw and pre-treated vinasse confirmed the conversion of humic- and/or phenolic-like molecules into protein-like metabolites. As a consequence, chemical oxygen demand of vinasse decreased by 53%. Interestingly, analysis of intracellular lipids of the biomass revealed high content in oleic acid and physical properties relevant for biodiesel application.ConclusionsThe soft-rot fungus A. niger demonstrated a great ability to grow on vinasse and to degrade this complex and hostile medium. The high biomass production is accompanied by a utilization of carbon sources like residual carbohydrates, organic acids and more complex molecules such as melanoidins. We also showed that intracellular lipids from fungal biomass can efficiently be exploited into biodiesel.Electronic supplementary materialThe online version of this article (10.1186/s40694-018-0045-6) contains supplementary material, which is available to authorized users.

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The calculation of airflows is of great importance for detailed building thermal simulation computer codes, these airflows most frequently constituting an important thermal coupling between the building and the outside on one hand, and the different thermal zones on the other.The driving effects of air movement, which are the wind and the thermal buoyancy, are briefly outlined and we look closely at their coupling in the case of buildings, by exploring the difficulties associated with large openings. Some numerical problems tied to the resolving of the non-linear system established are also covered. Part of a detailled simulation software (CODYRUN), the numerical implementation of this airflow model is explained, insisting on data organization and processing allowing the calculation of the airflows. Comparisons are then made between the model results and in one hand analytical expressions and in another and experimental measurements in case of a collective dwelling. 1-IntroductionRegarding the number of airflow network models found in building publications, it appears that the calculation of airflow is of great importance for detailed building airflow network modelling computer codes. In fact, these airflows most often constitute an important thermal coupling between the building and the outside and the different thermal zones. It is thus, that during the period when heating a residential building, approximately 30% of the energy loss is due to air renewal [1]. Furthermore, the airflow exchanged between two different zones, separated by a standard doorway with a temperature difference of 0.1 K is approximately 120 m 3 /h [2]. These airflows also play a major role in humidity displacement in the building (comfort, localised condensation risks, ...), the dispersion of pollutants [3,4] (smoke, gas flows ...), or in industrial [5] and farming buildings [6].The content of this paper is macroscopic in that it does not determine the temperatures, the pressures, or the average speeds for all points in the zone. The above approach can be arrived at by using simplifications associated with the Navier-Stokes infinitesimal volume equations [7]. In our case, the aim is to obtain an estimation of the exchanged airflows.Depending on the climate, these airflows must be considered differently. Thus in tropical climates, natural ventilation affects essentially the inside comfort by favouring evapo-perspiration through the air movement. The buildings in these latitudes are often very much open to the exterior and thus the airflow transfer aspect is extremely important. In temperate and cold climates, the energetic aspect is the determining factor in these airflow transfers. In fact the importance of ventilation in the energy consumption continues to rise due to better building insulation. -The driving effectsAs these notions have already been largely studied [9,10], only the necessary explanations for the comprehension of the paper will be covered. As well as wind and thermal buoyancy, mechanical ventilation by air extractors const...