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1.
Electron. j. biotechnol ; 27: 44-48, May. 2017. tab
Artigo em Inglês | LILACS | ID: biblio-1010289

RESUMO

Background: Depletion of petroleum resources has enforced the search for alternative sources of renewable energy. Introduction of biofuels into the market was expected to become a solution to this disadvantageous situation. Attempts to cover fuel demand have, however, caused another severe problem­the waste glycerol generated during biodiesel production at a concentration of approximately 10% w/w. This, in turn, prompted a global search for effective methods of valorization of the waste fraction of glycerol. Results: Utilization of the waste fraction at 48 h with an initial glycerol concentration of 30 g·L-1 and proceeding with 62% efficiency enabled the production of 9 g·L-1 dihydroxyacetone at 50% substrate consumption. The re-use of the immobilized biocatalyst resulted in a similar concentration of dihydroxyacetone (8.7 g·L-1) in two-fold shorter time, with an efficiency of 85% and lower substrate consumption (35%). Conclusions: The method proposed in this work is based on the conversion of waste glycerol to dihydroxyacetone in a reaction catalyzed by immobilized Gluconobacter oxydans cell extract with glycerol dehydrogenase activity, and it could be an effective way to convert waste glycerol into a valuable product.


Assuntos
Células Imobilizadas/metabolismo , Di-Hidroxiacetona/metabolismo , Glicerol/metabolismo , Resíduos , Extratos Celulares , Células Imobilizadas/química , Gluconobacter oxydans , Biocombustíveis , Reciclagem , Energia Renovável , Glicerol/química
2.
Braz. j. microbiol ; 47(1): 129-135, Jan.-Mar. 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-775107

RESUMO

Abstract The principal objective of this study was to evaluate the kinetics of dihydroxyacetone production by Gluconobacter frateurii CGMCC 5397 under different oxygen volumetric mass transfer coefficient (kLa) conditions in submerged bioreactors using biodiesel-derived crude glycerol as the carbon source. kLa is a key fermentation parameter for the production of dihydroxyacetone. Cultivations were conducted in baffled- and unbaffled-flask cultures (the kLa values were 24.32 h−1 and 52.05 h−1, respectively) and fed-batch cultures (the kLa values were held at 18.21 h−1, 46.03 h−1, and 82.14 h−1) to achieve high dihydroxyacetone concentration and productivity. The results showed that a high kLa could dramatically increase dihydroxyacetone concentrations and productivities. The baffled-flask culture (with a kLa of 52.05 h−1) favored glycerol utilization and dihydroxyacetone production, and a dihydroxyacetone concentration as high as 131.16 g/L was achieved. When the kLa was set to 82.14 h−1 in the fed-batch culture, the dihydroxyacetone concentration, productivity and yield were 175.44 g/L, 7.96 g/L/h and 0.89 g/g, respectively, all of which were significantly higher than those in previous studies and will benefit dihydroxyacetone industrial production.


Assuntos
Di-Hidroxiacetona/metabolismo , Gluconobacter/metabolismo , Glicerol/metabolismo , Oxigênio/metabolismo , Biotransformação , Reatores Biológicos/microbiologia , Carbono/metabolismo
3.
Arch. argent. dermatol ; 45(4): 147-50, jul.-ago. 1995. ilus
Artigo em Espanhol | LILACS | ID: lil-166036

RESUMO

El envejecimiento induce marcados cambios de la superficie cutánea y particularmente de la capa córnea. La aplicación de lipo-hidroxi-ácido, un derivado lipofílico del ácido salicílico, aporta una mejoría de ciertas alteraciones asociadas al envejecimiento. Produce una eliminación más uniforme de los corneocitos y un aumento del espesor de las capas basal y de Malpighi, dentro de los límites fisiológicos


Assuntos
Humanos , Idoso , Hidroxiácidos/uso terapêutico , Envelhecimento da Pele/efeitos dos fármacos , Ceratolíticos/uso terapêutico , Di-Hidroxiacetona , Hidroxiácidos/administração & dosagem , Hidroxiácidos/farmacologia , Envelhecimento da Pele/patologia , Envelhecimento da Pele/fisiologia
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