Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Mais filtros

Base de dados
Intervalo de ano de publicação
Sci Total Environ ; 918: 170448, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38301774


In the past decade, there has been a significant rise in sustainable biomass based biofuel production to address energy needs while mitigating environmental impacts. Traditionally, bioethanol was used for biofuel production, but concerns over food security and environmental preservation have led to growing interest in alternative sources such as neutral lipids from vegetable oil and microalgae for biodiesel production. This research paper evaluates the potential of various oleaginous plants and microalgae as feedstocks for biodiesel production, with a focus on their fatty acid composition and its impact on biodiesel properties. The study examines the fatty acid profiles of 43 different plant and microalgae species and employs various equations to estimate key physical properties of biodiesel. Additionally, the communication compares these properties to International Biodiesel Standards (EN 14214 and ASTM D6751-08) to assess the suitability of the derived biodiesel for commercial use. It is impossible to describe a single composition that is optimal in terms of all essential fuel properties due to the opposing effects of some structural features of the Fatty Acid Methyl Esters (FAME). However, biodiesel should contain relatively low concentrations of both long chain saturated and polyunsaturated FAME to ensure adequate efficiency in terms of low temperature operability and oxidative stability. The results reveal significant variations in properties amongst different feedstocks, highlighting the importance of feedstock selection in biodiesel production. The study also establishes correlations between various fuel properties, providing valuable insights in to optimizing biodiesel production processes, which will be of great use to researchers, engineers, and stakeholders involved in biodiesel production.

Ácidos Graxos , Microalgas , Ácidos Graxos/química , Biocombustíveis , Óleos de Plantas/química , Temperatura Baixa , Biomassa
Prog Biomater ; 9(3): 81-95, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32654045


The evolving technology of nanoparticle synthesis, especially silver nanoparticle (AgNPs) has already been applied in various fields i.e., electronics, optics, catalysis, food, health and environment. With advancement in research, it is possible to develop nanoparticles of various size, shape, morphology, and surface to volume ratio utilizing biological systems. A number of different agents and methods can be employed to develop choice based AgNPs using algae, plants, fungi and bacteria. The use of plant extracts to produce AgNPs appears to be more convenient, as the method is simple, environmental friendly and inexpensive, also requiring a single-step. The microbial synthesis of AgNps showed intracellular and extracellular mechanisms to reduce metal ions into nanoparticles. Studies have shown that different size (1-100 nm) and shapes (spherical, triangular and hexagonal etc.) of nanoparticles can be produced from various biological routes and these diverse nanoparticles have various functions and usability i.e., agriculture, medical-science, textile, cosmetics and environment protection. The present review provides an overview of various biological systems used for AgNP synthesis, its underlying mechanisms, further highlighting the current research and applications of variable shape and sized AgNPs.

Environ Sci Pollut Res Int ; 22(2): 1499-511, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25163561


Bacterial community of palaeoproterozoic metasediments was enriched in the chemostat in the presence of different concentrations of NaHCO3. Six bacterial isolates were isolated from the chemostat on nutrient agar plates on the basis of distinct morphology. Denaturing gradient gel electrophoresis (DGGE) proved the presence of six operational taxonomic units (OTUs) at 50 and 100 mM NaHCO3. The OTU was reduced to three and one at enrichment concentration of 150 and 200 mM NaHCO3 respectively. These six isolates were tested for sequestration of carbon dioxide by (14)C metabolic labeling of NaH(14)CO3. Among the six isolates, one of the bacterium showed better potency to fix radiolabeled NaH(14)CO3. The isolate (ISTD04) was identified as Serratia sp. by 16S ribosomal RNA (16S rRNA) sequence analysis and was found to be same as the DGGE OTU sequence at 200-mM NaHCO3 concentration. The bacterium was tested for product formation in form of calcite crystals in presence of 5 % CO2. Scanning electron microscopy (SEM) of product formed by the bacterium revealed defined faceted rhombohedral structure which resembled calcite and vaterite phases of the crystal. Formation of calcium carbonate crystals was further confirmed by Fourier transform infrared (FTIR) spectroscopy as carbonate group showing strong vibration at 1,456 cm(-1). Major calcite phase diffraction peaks were determined by X-ray diffraction (XRD) analysis, and energy-dispersive X-ray (EDX) analysis showed the presence of CaO (72 %) and carbon (18 %). Bacterium use bicarbonate as carbon source for their growth as well as by-product formation in form of calcite shows carbon circulation and storage.

Carbonato de Cálcio/metabolismo , Dióxido de Carbono/metabolismo , Sequestro de Carbono/fisiologia , Sedimentos Geológicos/microbiologia , Aquecimento Global/prevenção & controle , Serratia/metabolismo , Microbiologia do Solo , Radioisótopos de Carbono/análise , Eletroforese em Gel de Gradiente Desnaturante , Microscopia Eletrônica de Varredura , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Serratia/genética , Bicarbonato de Sódio , Especificidade da Espécie , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
PLoS One ; 9(3): e91300, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24619032


A chemolithotrophic bacterium enriched in the chemostat in presence of sodium bicarbonate as sole carbon source was identified as Serratia sp. by 16S rRNA sequencing. Carbon dioxide sequestering capacity of bacterium was detected by carbonic anhydrase enzyme and ribulose-1, 5- bisphosphate carboxylase/oxygenase (RuBisCO). The purified carbonic anhydrase showed molecular weight of 29 kDa. Molecular weight of RuBisCO was 550 kDa as determined by fast protein liquid chromatography (FPLC), however, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed presence of two subunits whose molecular weights were 56 and 14 kDa. The Western blot analysis of the crude protein and purified sample cross reacted with RuBisCO large-subunit polypeptides antibodies showed strong band pattern at molecular weight around 56 kDa regions. Whole cell soluble proteins of Serratia sp. grown under autotrophic and heterotrophic conditions were resolved by two-dimensional gel electrophoresis and MALDI-TOF/MS for differential expression of proteins. In proteomic analysis of 63 protein spots, 48 spots were significantly up-regulated in the autotrophically grown cells; seven enzymes showed its utilization in autotrophic carbon fixation pathways and other metabolic activities of bacterium including lipid metabolisms indicated sequestration potency of carbon dioxide and production of biomaterials.

Dióxido de Carbono/metabolismo , Carbono/metabolismo , Crescimento Quimioautotrófico , Proteômica , Serratia/crescimento & desenvolvimento , Serratia/metabolismo , Aminoácidos/metabolismo , Anidrases Carbônicas/isolamento & purificação , Anidrases Carbônicas/metabolismo , Ácidos Graxos/metabolismo , Nucleotídeos/metabolismo , Proteoma , Proteômica/métodos , RNA Ribossômico 16S/genética , Proteínas Ribossômicas/metabolismo , Serratia/genética
Bioresour Technol ; 165: 201-4, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24650615


A CO2 sequestering bacterial strain, Serratia sp. ISTD04, that produces a significant amount of extracellular lipids was isolated from marble mine rocks. (14)C labeling analysis revealed that the rate of assimilation of CO2 by the strain is 0.756×10(-9)µmolCO2fixedcell(-1)h(-1). It was found to produce 466mg/l of extracellular lipid which was characterized using (1)H NMR. After transesterification of lipids, the total saturated and unsaturated FAME was found to be 51% and 49% respectively. The major FAME contained in the biodiesel were palmitic acid methyl ester (C16:0), oleic acid methyl ester (C18:1) and 10-nonadecenoic acid methyl ester (C19:1). Biodiesel produced by Serratia sp. ISTD04 is balanced in terms of FAME composition of good quality. It also contained higher proportion of oleic acid (35%) which makes it suitable for utilization in existing engines. Thus, the strain can be harnessed commercially to sequester CO2 into biodiesel.

Biocombustíveis , Biotecnologia/métodos , Crescimento Quimioautotrófico , Lipídeos/isolamento & purificação , Serratia/metabolismo , Dióxido de Carbono/metabolismo , Ésteres/metabolismo , Espaço Extracelular/química
Bioresour Technol ; 153: 189-97, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24365740


A chemolithotrophic bacterium, Serratia sp. ISTD04, enriched in the chemostat in presence of sodium bicarbonate as sole carbon source was evaluated for potential of carbon dioxide (CO2) sequestration and biofuel production. CO2 sequestration efficiency of the bacterium was determined by enzymatic activity of carbonic anhydrase and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Further, Western blot analysis confirmed presence of RuBisCO. The bacterium produced 0.487 and 0.647mgmg(-1) per unit cell dry weight of hydrocarbons and lipids respectively. The hydrocarbons were within the range of C13-C24 making it equivalent to light oil. GC-MS analysis of lipids produced by the bacterium indicated presence of C15-C20 organic compounds that made it potential source of biodiesel after transesterification. GC-MS, FTIR and NMR spectroscopic characterization of the fatty acid methyl esters revealed the presence of 55% and 45% of unsaturated and saturated organic compounds respectively, thus making it a balanced biodiesel composition.

Biocombustíveis/microbiologia , Biotecnologia/métodos , Dióxido de Carbono/farmacologia , Crescimento Quimioautotrófico/efeitos dos fármacos , Serratia/metabolismo , Bioensaio , Esterificação/efeitos dos fármacos , Ésteres/análise , Hidrocarbonetos/metabolismo , Lipídeos/análise , Espectroscopia de Ressonância Magnética , Ribulose-Bifosfato Carboxilase/metabolismo , Serratia/efeitos dos fármacos , Serratia/crescimento & desenvolvimento , Serratia/isolamento & purificação , Hidróxido de Sódio/farmacologia