RESUMEN
Phaeodactylum tricornutum was cultivated mixotrophically in batch mode providing glycerol as the C source, i.e., 0.02, 0.03 and 0.04 Mol L-1 glycerol, and ultrafiltered digestate (UF) as an N source. Biomass productivity, biomass composition, N efficiency use and total energy balance were recorded and compared to those under autotrophic conditions. Under mixotrophic conditions (0.03 Mol L-1 and 0.04 Mol L-1 glycerol), biomass productivity of P. tricornutum increased by 1.29 and 1.60 times in comparison with autotrophic conditions. Algal protein content declined as glycerol concentration increased, contrary to the case of the carbohydrate content. Lipid content did not change but unexpectedly, a lower unsaturated fatty acid in mixotrophic culture was observed than that from autotrophic culture. Mixotrophic conditions offered a higher energy recovery efficiency (EFt) than autotrophic conditions (5.7 % in 0.04 Mol L-1 glycerol and 4.2 % in autotrophic trial, respectively). Additionally, the efficiency of glycerol conversion into biomass (EFgly) increased with the glycerol dose, achieving 22.8 % for 0.04 Mol L-1 glycerol.
Asunto(s)
Carbono/metabolismo , Medios de Cultivo/química , Diatomeas/crecimiento & desarrollo , Diatomeas/metabolismo , Glicerol/metabolismo , Nitrógeno/metabolismo , Procesos Autotróficos , Biomasa , Metabolismo de los Hidratos de Carbono , Carbohidratos , Ácidos Grasos/metabolismo , Ácidos Grasos Insaturados/metabolismo , Microalgas/metabolismo , Agua de MarRESUMEN
In this work, white wine lees (WWL), cheese whey (CW), and glycerol (GLY) were used as carbon (C) sources to mixotrophically support the production of the microalga Nannochloropsis salina, replacing CO2 supply. In doing so, the alga was allowed to grow on C sources dosed at 2 g L-1, 3 g L-1, and 4 g L-1 of C, in the presence and absence of CO2 supply. WWL and CW were not able to support the algal growth due to a fungal contamination that was genomically identified, while GLY gave interesting results in particular with 3 g L-1 of C. GLY-C was able to replace CO2-C completely when the latter was omitted, showing an algal biomass production similar to those obtained in autotrophy. If CO2-C was provided jointly with GLY-C, biomass production and lipid contents increased more than 30% and 23%, respectively, compared to autotrophy.
Asunto(s)
Dióxido de Carbono/metabolismo , Lípidos/biosíntesis , Microalgas/crecimiento & desarrollo , Estramenopilos/crecimiento & desarrollo , Aguas Residuales/microbiologíaRESUMEN
A local strain of Chlorella vulgaris was cultivated by using cheese whey (CW), white wine lees (WL) and glycerol (Gly), coming from local agro-industrial activities, as C sources (2.2gCL-1) to support algae production under mixotrophic conditions in Lombardy. In continuous mode, Chlorella increased biomass production compared with autotrophic conditions by 1.5-2 times, with the best results obtained for the CW substrate, i.e. 0.52gL-1d-1 of algal biomass vs. 0.24gL-1d-1 of algal biomass for autotrophic conditions, and protein content for both conditions adopted close to 500gkg-1 DM. Mixotrophic conditions gave a much higher energy recovery efficiency (EF) than autotrophic conditions, i.e. organic carbon energy efficiency (EFoc) of 32% and total energy efficiency (Eft) of 8%, respectively, suggesting the potential for the culture of algae as a sustainable practice to recover efficiently waste-C and a means of local protein production.
Asunto(s)
Agricultura , Biotecnología/métodos , Chlorella vulgaris/crecimiento & desarrollo , Alimentos , Proteínas/metabolismo , Aminoácidos/análisis , Procesos Autotróficos , Técnicas de Cultivo Celular por Lotes , Biomasa , Chlorella vulgaris/metabolismo , Glicerol/análisis , Nitrógeno/análisis , Fósforo/análisisRESUMEN
During walking on an instrumented treadmill with an embedded force platform or grid of pressure sensors, center-of-pressure (COP) trajectories exhibit a characteristic butterfly-like shape, reflecting the medio-lateral and anterior-posterior weight shifts associated with alternating steps. We define "gaitography" as the analysis of such COP trajectories during walking (the "gaitograms"). It is currently unknown, however, if gaitography can be employed to characterize pathological gait, such as lateralized gait impairments. We therefore registered gaitograms for a heterogeneous sample of persons with a trans-femoral and trans-tibial amputation during treadmill walking at a self-selected comfortable speed. We found that gaitograms directly visualize between-person differences in prosthetic gait in terms of step width and the relative duration of prosthetic and non-prosthetic single-support stance phases. We further demonstrated that one should not only focus on the gaitogram's shape but also on the time evolution along that shape, given that the COP evolves much slower in the single-support phase than in the double-support phase. Finally, commonly used temporal and spatial prosthetic gait characteristics were derived, revealing both individual and systematic differences in prosthetic and non-prosthetic step lengths, step times, swing times, and double-support durations. Because gaitograms can be rapidly collected in an unobtrusive and markerless manner over multiple gait cycles without constraining foot placement, clinical application of gaitography seems both expedient and appealing. Studies examining the repeatability of gaitograms and evaluating gaitography-based gait characteristics against a gold standard with known validity and reliability are required before gaitography can be clinically applied.