Microalga biomass has been described worldwide according their capacity to realize biosorption of toxic metals. Chromium is one of the most toxic metals that could contaminate superficial and underground water. Considering the importance of Spirulina biomass in production of supplements for humans and for animal feed we assessed the biosorption of hexavalent chromium by living Spirulina platensis and its capacity to convert hexavalent chromium to trivalent chromium, less toxic, through its metabolism during growth. The active biomass was grown in Zarrouk medium diluted to 50% with distilled water, keeping the experiments under controlled conditions of aeration, temperature of 30°C and lighting of 1,800 lux. Hexavalent chromium was added using a potassium dichromate solution in fed-batch mode with the aim of evaluate the effect of several additions contaminant in the kinetic parameters of the culture. Cell growth was affected by the presence of chromium added at the beginning of cultures, and the best growth rates were obtained at lower metal concentrations in the medium. The biomass removed until 65.2% of hexavalent chromium added to the media, being 90.4% converted into trivalent chromium in the media and 9.6% retained in the biomass as trivalent chromium (0.931 mg.g(-1)).
RESUMOO inadequado descarte de efluentes contendo metais tóxicos em altas concentrações representa um grave problema para o meio ambiente, sendo o cromo hexavalente um dos metais tóxicos que tem recebido atenção, devido a sua alta toxicidade. A biossorção é uma tecnologia que se caracteriza como alternativa para a remoção destes compostos de efluentes, devido ao menor preço do material biossorvente e baixo custo operacional. O objetivo foi avaliar a remoção de cromo hexavalente de efluente por meio do processo de biossorção utilizando resíduos agroindustriais fermentados com fungos filamentosos do gênero Aspergillus. A máxima remoção de cromo hexavalente foi de 58%, utilizando-se 2% de biossorvente composto por farelo de soja e casca de arroz fermentados com Aspergillus flavus cepa O-8, com biomassa morta por meio de tratamento térmico por esterilização e concentração inicial de cromo hexavalente de 120 mg/L. Este resultado pode ser otimizado por meio do estudo de condições reacionais como pH e agitação. Palavras-chave: biossorção, casca de arroz, cromo hexavalente, farelo de soja, fungos. ABSTRACTThe inappropriate disposal of effluents containing toxic metals in high concentrations is a serious problem for the environment, and hexavalent chromium has received attention due to its high toxicity. The biosorption is a technology characterized as an alternative to remove these compounds from wastewater, due to lower material cost and lower operating costs of biosorbents. The aim of this work was to evaluate the removal of hexavalent chromium of effluent by biosorption using agroindustrial wastes fermented with fungi of the genus Aspergillus. The maximum hexavalent chromium removal was of 58%, using 2% biosorbent produced by solid state fermentation of soybean and rice husk using Aspergillus O-8 strain. The biomass was submitted to heat treatment for sterilization and the initial concentration of hexavalent chromium in the medium was 120 mg/L. This result can be optimized through the study of reaction conditions such as pH and agitation.
ResumoO potencial de contaminação de solos por vazamentos de óleos vem crescendo, devido à forte industrialização e o desenvolvimento econômico dos países. Diante desse cenário, a biorremediação tem se mostrado uma alternativa para remediar áreas mediante uso de agentes biológicos. Dois microorganismos, isolados de um efluente rico em lipídios, foram utilizadas nos ensaios de bioaumentação em solos contaminados com óleo diesel, óleo lubrificante e óleo de soja. Ensaios de atenuação natural foram realizados como controles. As remoções do óleo diesel no tempo de 21 d foram de 18,5%, 7,30% e 11,38% respectivamente, para as técnicas de bioaumento com os isolados I1 e I2 e atenuação natural. As remoções do óleo lubrificante foram de 41,6%, 14,16% e 6,91% respectivamente, para as técnicas de bioaumento com os isolados I1 e I2 e atenuação natural, enquanto que para o óleo de soja as remoções foram de 87,8%, 73,9% e 49,4%. Considerando-se as técnicas de bioaumento e atenuação natural, o bioaumento com o isolado I1 apresentou melhores resultados, possivelmente devido à produção de compostos com capacidade de diminuição da tensão superficial durante a fase de preparo do bioaumento. Palavras-chave: Óleo Diesel. Óleo lubrificante. Óleo de soja. Efluente de laticínios. Isolamento de micro-organismos para biorremediação. AbstractThe potential for soil contamination by oil spills is growing, due to heavy industrialization and economic development of countries. Due to this fact, the bioremediation has become an alternative to remediate areas through the use of biological agents. Two microorganisms, isolated from a lipid-rich effluent, were used in the bioaugmentation of soils contaminated with diesel oil, lubricating oil and soybean oil. Natural attenuation tests were conducted as controls. The removal of diesel fuel at the time of 21 d were of 18.5%, 7.30% and 11.38%, respectively, for the bioaugmentation with isolated I1 and I2 and natural attenuation. The removal of lubricating oil were 41.6%, 14.16% and 6.91% respectively for the
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.