25,959 research outputs found
PREPARATION PRELIMINARY STUDY OF BIODEGRADABLE PLASTICS BASED OF CASSAVA COMPOUNDS WITH ADDITIVES LIMONENE EXTRACTION OF ORANGE LEATHER
Biodegradable plastic is a plastic material that is environmentally friendly because it is able to return to nature. In general, biodegradable packaging films is defined as packaging that is recyclable and can be destroyed by nature. Cassava starch can be an alternative biodegradable plastic raw materials. The manufacturing process is similar to the process of making plastics with the raw material of synthetic polymers. Biodegradable plastics are new breakthroughs to deliver maximum results, with the base material of cassava and the addition compound limonene, the thickness of relatively thin plastic, the stronger the attraction, elasticity longer. The purpose of this study was to determine the optimum conditions to produce biodegradable plastics with the compound limonene (additive) from the extraction of orange peel. Research conducted through three stages: (1) extraction of orange peel, (2) extraction of cassava starch, and (3) the manufacture of biodegradable plastics. Variable is an experiment conducted on susceptible starch concentration of 4-6% and 5-7% concentration of sorbitol. While the cooking temperature between 70-80oC and the addition of an additive compound of orange peel extract as much as 15%. Of research can be seen that the concentration of cassava starch, sorbitol concentration and the concentration of limonene compounds influencing parameters tested. Percent extension treatment with the highest concentrations found in cassava starch 6%, 7% sorbitol concentration, and concentration of the compound limonene 15%. Relatively good condition or optimum in the manufacture of biodegradable plastics at 80 oC.
Keywords: biodegradable plastic, cassava starch, limonene, orange pee
Evaluation of antioxidant activity of the fermented product from the biotransformation of R-(+)-limonene in solid-state fermentation of orange waste by Diaporthe sp.
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Multiphase composition changes and reactive oxygen species formation during limonene oxidation in the new Cambridge Atmospheric Simulation Chamber (CASC)
open7openGallimore, Peter J.; Mahon, Brendan M.; Wragg, Francis P. H.; Fuller, Stephen J.; Giorio, Chiara; Kourtchev, Ivan; Kalberer, MarkusGallimore, Peter J.; Mahon, Brendan M.; Wragg, Francis P. H.; Fuller, Stephen J.; Giorio, Chiara; Kourtchev, Ivan; Kalberer, Marku
Assessment of different pre-treatment methods for the removal of limonene in citrus waste and their effect on methane potential and methane production rate
The objective of this study was to assess the limonene removal efficiency of three pre-treatment methods when applied to citrus waste and to evaluate their effects on the biochemical methane potential (BMP)
and the methane production rate (MPR) using batch anaerobic testsPostprint (published version
Effect of the essential oil of Minthostachys verticillata (Griseb.) epling and limonene on biofilm production in pathogens causing bovine mastitis
Bovine mastitis causes large annual economic losses around the world. Different microorganisms are associated with the disease. The capacity of pathogens to adhere to bovine mammary epithelial cells is associated with biofilm production which leads to antibiotic resistance. Research is now leading to search alternative control methods and medicinal plants constitute a natural, safe, effective and inexpensive option. Minthostachys verticillata is an autochthonous medicinal plant of Argentina with multiple ethnobotanical properties. In a previous study, we demonstrated that the essential oil (EO) of this species and limonene, one of its compounds, inhibited the growth of mastitis pathogens. The objective of the present work was to determine the inhibitory effect of the essential oil of M. verticillata and limonene, on biofilm formation and on mature biofilm produced by pathogens isolated from bovine mastitis. Time kill assay and bacterial lysis were also determined. Furthermore, RAPD-PCR assays were performed to determine changes in bacterial DNA after EO and limonene exposition. Bacterial isolates were identified as Escherichia coli (EC3 and EC9), Bacillus pumilus (BP5, BP6, and BP7) and Enterococcus faecium (EF1) by rRNA 16S sequencing and MALDI-TOF MS. All the strains were able to form biofilm. Addition of both lactose and sucrose did not affect biofilm production. MIC values for EO were 3.6 mg/ml for E. faecium; 0.9 mg/ml for E. coli (EC3), 14.5 mg/ml for E. coli (EC9), 1.8 mg/ml for B. pumilus (BP7), 3.63 mg/ml for B. pumilus (BP6) and 29.0 mg/ml for B. pumilus (BP7). MIC values for limonene were 6.6 mg/ml for B. pumilus (BP6) and 105 mg/ml for B. pumilus (BP5). These results demonstrated that EO was more effective than limonene, showing also bactericidal action against E. faecium (minimal inhibitory concentration (MBC) = 29.0 mg/ml). This result was corroborated by time of death assay, observing a cell decrease after at 6 h, and then by bacterial lysis assay. Both EO and limonene affected mature biofilm of isolated strains. The results contribute to the study of EO and limonene which may serve as a therapy against bovine mastitis pathogens inhibiting the development of pathogenic bacteria.Fil: Cerioli, Maria Florencia. Universidad Nacional de RĂo Cuarto; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Moliva, Melina Vanesa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de RĂo Cuarto; ArgentinaFil: Cariddi, Laura Noelia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de RĂo Cuarto; ArgentinaFil: Reinoso, Elina BeatrĂz. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de RĂo Cuarto; Argentin
The oxygen-independent metabolism of cyclic monoterpenes in Castellaniella defragrans 65Phen
BACKGROUND: The facultatively anaerobic betaproteobacterium Castellaniella defragrans 65Phen utilizes acyclic, monocyclic and bicyclic monoterpenes as sole carbon source under oxic as well as anoxic conditions. A biotransformation pathway of the acyclic ÎČ-myrcene required linalool dehydratase-isomerase as initial enzyme acting on the hydrocarbon. An in-frame deletion mutant did not use myrcene, but was able to grow on monocyclic monoterpenes. The genome sequence and a comparative proteome analysis together with a random transposon mutagenesis were conducted to identify genes involved in the monocyclic monoterpene metabolism. Metabolites accumulating in cultures of transposon and in-frame deletion mutants disclosed the degradation pathway. RESULTS: Castellaniella defragrans 65Phen oxidizes the monocyclic monoterpene limonene at the primary methyl group forming perillyl alcohol. The genome of 3.95Â Mb contained a 70Â kb genome island coding for over 50 proteins involved in the monoterpene metabolism. This island showed higher homology to genes of another monoterpene-mineralizing betaproteobacterium, Thauera terpenica 58Eu(T), than to genomes of the family Alcaligenaceae, which harbors the genus Castellaniella. A collection of 72 transposon mutants unable to grow on limonene contained 17 inactivated genes, with 46 mutants located in the two genes ctmAB (cyclic terpene metabolism). CtmA and ctmB were annotated as FAD-dependent oxidoreductases and clustered together with ctmE, a 2Fe-2S ferredoxin gene, and ctmF, coding for a NADH:ferredoxin oxidoreductase. Transposon mutants of ctmA, B or E did not grow aerobically or anaerobically on limonene, but on perillyl alcohol. The next steps in the pathway are catalyzed by the geraniol dehydrogenase GeoA and the geranial dehydrogenase GeoB, yielding perillic acid. Two transposon mutants had inactivated genes of the monoterpene ring cleavage (mrc) pathway. 2-Methylcitrate synthase and 2-methylcitrate dehydratase were also essential for the monoterpene metabolism but not for growth on acetate. CONCLUSIONS: The genome of Castellaniella defragrans 65Phen is related to other genomes of Alcaligenaceae, but contains a genomic island with genes of the monoterpene metabolism. Castellaniella defragrans 65Phen degrades limonene via a limonene dehydrogenase and the oxidation of perillyl alcohol. The initial oxidation at the primary methyl group is independent of molecular oxygen
Greener and sustainable method for alkene epoxidations by polymer-supported Mo(VI) catalysts
A polybenzimidazole supported Mo(VI) (PBI.Mo) catalyst has been prepared and characterised. The catalytic activities of the PBI.Mo catalyst in epoxidation of alkenes with tert-butyl hydroperoxide (TBHP) as an oxidant have been studied under different reaction conditions in a batch reactor. As alkene representatives we have chosen cyclohexene, limonene, α-pinene and 1-octene (a less reactive terminal alkene). The order of reactivity of the alkenes was found to be: cyclohexene>limonene>α-pinene>1-octene. The stability of each polymer catalyst was assessed by recycling a sample in batch reaction using conditions that will form the basis of the continuous process. The loss of Mo from each support has been investigated by isolating any residue from the reaction supernatant solutions, following removal of the heterogeneous polymer catalyst, and then using the residues as potential catalysts in epoxidation reactions
A synthetic biochemistry platform for cell free production of monoterpenes from glucose.
Cell-free systems designed to perform complex chemical conversions of biomass to biofuels or commodity chemicals are emerging as promising alternatives to the metabolic engineering of living cells. Here we design a system comprises 27 enzymes for the conversion of glucose into monoterpenes that generates both NAD(P)H and ATP in a modified glucose breakdown module and utilizes both cofactors for building terpenes. Different monoterpenes are produced in our system by changing the terpene synthase enzyme. The system is stable for the production of limonene, pinene and sabinene, and can operate continuously for at least 5 days from a single addition of glucose. We obtain conversion yields >95% and titres >15âgâl-1. The titres are an order of magnitude over cellular toxicity limits and thus difficult to achieve using cell-based systems. Overall, these results highlight the potential of synthetic biochemistry approaches for producing bio-based chemicals
Organosulfate Formation in Biogenic Secondary Organic Aerosol
Organosulfates of isoprene, α-pinene, and ÎČ-pinene have recently been identified in both laboratory-generated and ambient secondary organic aerosol (SOA). In this study, the mechanism and ubiquity of organosulfate formation in biogenic SOA is investigated by a comprehensive series of laboratory photooxidation (i.e., OH-initiated oxidation) and nighttime oxidation (i.e., NO3-initiated oxidation under dark conditions) experiments using nine monoterpenes (α-pinene, ÎČ-pinene, d-limonene, l-limonene, α-terpinene, Îł-terpinene, terpinolene, Î3-carene, and ÎČ-phellandrene) and three monoterpenes (α-pinene, d-limonene, and l-limonene), respectively. Organosulfates were characterized using liquid chromatographic techniques coupled to electrospray ionization combined with both linear ion trap and high-resolution time-of-flight mass spectrometry. Organosulfates are formed only when monoterpenes are oxidized in the presence of acidified sulfate seed aerosol, a result consistent with prior work. Archived laboratory-generated isoprene SOA and ambient filter samples collected from the southeastern U.S. were reexamined for organosulfates. By comparing the tandem mass spectrometric and accurate mass measurements collected for both the laboratory-generated and ambient aerosol, previously uncharacterized ambient organic aerosol components are found to be organosulfates of isoprene, α-pinene, ÎČ-pinene, and limonene-like monoterpenes (e.g., myrcene), demonstrating the ubiquity of organosulfate formation in ambient SOA. Several of the organosulfates of isoprene and of the monoterpenes characterized in this study are ambient tracer compounds for the occurrence of biogenic SOA formation under acidic conditions. Furthermore, the nighttime oxidation experiments conducted under highly acidic conditions reveal a viable mechanism for the formation of previously identified nitrooxy organosulfates found in ambient nighttime aerosol samples. We estimate that the organosulfate contribution to the total organic mass fraction of ambient aerosol collected from K-puszta, Hungary, a field site with a similar organosulfate composition as that found in the present study for the southeastern U.S., can be as high as 30%
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