Norma G. Rojas-Avelizapa

Bio: Norma G. Rojas-Avelizapa is an academic researcher from Instituto Politécnico Nacional. The author has contributed to research in topics: Bacillus megaterium & Cadmium sulfide. The author has an hindex of 12, co-authored 44 publications receiving 351 citations. Previous affiliations of Norma G. Rojas-Avelizapa include Mexican Institute of Petroleum.

A field trial for an ex-situ bioremediation of a drilling mud-polluted site

Abstract: The remediation of drilling mud-polluted sites in the Southeast of Mexico is a top priority for Mexican oil industry. The objective of this work was to find a technology to remediate these sites. A field trial was performed by composting in biopiles, where four 1 ton soil-biopiles were established, one treatment in triplicate and one unamended biopile. Amended biopiles were added with nutrients to get a C/N/P ratio of 100/3/0.5 plus a bulking agent (straw) at a soil/straw ratio of 97/3. Moisture content was maintained around 30–35%. Results showed that, after 180 d, total petroleum hydrocarbon (TPH) concentrations decreased from 99 300 ± 23 000 mg TPH kg −1 soil to 5500 ± 770 mg TPH kg −1 for amended biopiles and to 22 900 ± 7800 mg TPH kg −1 for unamended biopile. An undisturbed soil control showed no change in TPH concentrations. Gas chromatographic analysis showed residual alkyl dibenzothiophene type compounds. Highest bacterial counts were observed during the first 30 d which correlated with highest TPH removal, whereas fungal count increased at the end of the experimentation period. Results suggested an important role of the straw, nutrient addition and water content in stimulating aerobic microbial activity and thus hydrocarbon removal. This finding opens an opportunity to remediate old polluted sites with recalcitrant and high TPH concentration.

Identification of recalcitrant hydrocarbons present in a drilling waste-polluted soil

Abstract: During spills of hydrocarbons in soil, it has been observed that aliphatic and the slightly aromatic hydrocarbons are first to be removed, however, branched aliphatic and aromatic compounds, polycyclic aromatic hydrocarbons (PAHs) and their similar heteroatoms with sulfur (PAS) remain strongly absorbed to soil particles. It is important to point out that studies of biodegradation of alkyl-substituted PAHs and PAS are scarce and most of them have been carried out using only available standard compounds. The aim of this investigation was to identify and to quantify the aliphatic, alkyl polycyclic aromatic, and sulfured recalcitrant fractions present in a contaminated soil with drilling wastes. A modified method of shaking-centrifugation extraction was implemented for the extraction of compounds from contaminated soil. The organic extract obtained was purified and fractionated using aluminum oxide. Gas Chromatograph with flame ionization detector (GC-FID) and Gas Chromatograph with mass spectrometer detector (GC-MS) identified the aliphatic, PAHs and PAS fractions. Hydrocarbon composition in the soil contaminated with 140,000 mg TPHs/Kg soil, consisted in 80% of branched aliphatic compounds of C10 to C22, 15% of alkyl PAHs, and 5% of PAS compounds. Lineal, lineal branched, and cyclic branched aliphatic hydrocarbons, as well as their alkyl naphthalene, anthracene and phenantrene, methyldibenzothiophene, dimethyldibenzothiophene, and dimethylnaphto[2,3-b]thiophene compounds were identified by CG-MS. The identification of compounds in soil P31, allowed us to speculate on the origin of the contamination and the natural attenuation that had occurred at this site.

Solid culture amended with small amounts of raw coffee beans for the removal of petroleum hydrocarbon from weathered contaminated soil

Abstract: Solid culture with small amounts of low-quality raw coffee beans was used for total petroleum hydrocarbon (TPH) removal from a weathered and polluted soil. Soil contaminated with 58 000 mg kg −1 of TPH was treated with soil:coffee bean ratios of 98:2, 96:4, 94:6, and 92:8, at a C:N:P ratio of 100:10:1, 20% humidity, and 28 °C, for periods of 15, 60, and 90 days. The highest TPH removal (63%) was obtained with a soil/bean ratio of 98:2 over 15 days, corresponding with the highest rates of microbial respiration and the greatest increases in bacterial and fungal counts to 9 lnCFU and 6 lnCFU, respectively. Scanning electron microscopy showed high fungal colonization of coffee beans, with Mucor sp., Aspergillus sp., Aspergillus niger. , and Penicillium sp. growing on TPH as sole carbon source.

Oil-removal enhancement in media with keratinous or chitinous wastes by hydrocarbon-degrading bacteria isolated from oil-polluted soils.

Abstract: The aim of this work was to isolate oil-degrading bacteria that use chitin or keratin as carbon sources from oil contaminated soils; and additionally to study if oil removal by these bacteria is enhanced when a chitinous or a keratinous waste is added to the culture media. To isolate the above-mentioned bacteria, 12 soil samples were collected close to an oil-well. Such soils showed unsuitable nutrients content, but their counts of heterotrophic bacteria ranged within 10(5)-10(8) CFU g(-1) soil, of which 0.1-77% corresponded to oil hydrocarbon-degrading ones. By sampling on plates, 109 oil-degrading bacterial isolates were obtained. Their keratinase and chitinase activities were then screened by plate assays and spectrophotometric methods, resulting in 13 isolates that were used to integrate two mixed cultures, one keratinolytic and the other chitinolytic. These mixed cultures were grown in media with oil, or oil supplemented with chicken-feathers or shrimp wastes. The oil-hydrocarbon removal was measured by gas chromatography. Results showed that keratinolytic bacteria were better enzyme producers than the chitinolytic ones, and that oil removal in the presence of chicken-feathers was 3.8 times greater than with shrimp wastes, and almost twice, in comparison with oil-only added cultures. Identification of microorganisms from the mixed cultures by 16S rDNA, indicated the presence of seven different bacterial genera; Stenotrophomonas, Pseudomonas, Brevibacillus, Bacillus, Micrococcus, Lysobacter and Nocardiodes. These findings suggest that the isolated microorganisms and the chicken-feather wastes could be applied to the cleaning of oil-contaminated environments, whether in soil or water.

Synthesis of Cadmium Sulfide Nanoparticles by Biomass of Fusarium oxysporum f. sp. lycopersici

Abstract: This study describes extracellular biosynthesis of cadmium sulfide quantum dots by Fusarium oxysporum f. sp. lycopersici. Mycelia was incubated with a cadmium sulfate solution at 30°C and after 12 days the mixture became yellow, then the biomass was discarded through paper filtration. The filtrate containing extracellular cadmium sulfide quantum dots displayed increased UV-Vis absorption from 300 - 500 nm and fluorescence at 520 nm which was not shown when incubated without cadmium sulfide, thus indicating the presence of biologically synthesized quantum dots. Transmission electron microscope analysis of biologically synthesized quantum dots evinced individual 2 - 6 nm diameter circular nanoparticles of uniform size. Energy dispersive spectroscopy confirmed the presence of S and Cd. Additionally, this study showed the relevance in the use of positive and negative controls when evaluating the biosynthesis of CdS quantum dots using UV-Vis and fluorescence spectrophotometry.

Soil enzymes: Kuprevich, V. F. & Shcherbakova, T. A.: Translated from the Russian edition (1966), published by the Indian National Scientific Documentation Centre, New Delhi 1971. 392 pp., offset printing from type script, paper cover. Obtainable from U.S. Department of Commerce, National Technical Information Service, Springfield, Va. 22151

Abstract: B6nassy, C., 1955. R6marques sur deux Aphelinid6s: Aphelinus mytilaspidis Le Baron et Aphytis proclia Walker. Annls l~piphyt. 6: 11-17. Lord, F. T. & MacPhee, A. W., 1953. The influence of spray programs on the fauna of apple orchards in Nova Scotia II. Oyster shell scale. Can. Ent. 79: 196-209. Pickett, A. D., 1946. A progress report on long term spray programs. Rep. Nova Scotia Fruit Grow. Ass. 83 : 27-31. Pickett, A. D., 1967. The influence of spray programs on the fauna of apple orchards in Nova Scotia XIV. Can. Ent. 97: 816-821. Tothill, J. D., 1918. The predacious mite Hemisarcoptes malus Shimer and its relation to the natural control of the oyster shell scale Lepidosaphes ulmi L. Agric. Gaz. Can. 5 : 234-239.

Advances in green synthesis of nanoparticles

Abstract: Nanotechnology is a developing branch of pharmaceutical sciences wherein the particles extend in nanosizes and turn out to be more responsive when contrasted with their unique counter parts. In the past numerous years, the utilization of synthetic concoctions and physical strategies were in mould; however, the acknowledgment of their toxic impacts on human well-being and condition influenced serious world view for the researchers. Presently, green synthesis is the watch word for the combination of nanoparticles (NPs) by plants or their metabolites. This innovation is particularly compensating as far as decreasing the poisonous quality caused by the conventionally integrated NPs. In this review, we cover the perspectives by which metal particles can be integrated from green methods in the perspective of green methods utilized in the NPs combination. In the green strategies, plant metabolites and natural substances are utilized to orchestrate the NPs for the pharmaceutical and other applications. Some characterization methods are also reviewed along with applications of NPs.

Phytoremediation of petroleum contaminated soils by Mirabilis Jalapa L. in a greenhouse plot experiment

Abstract: Phytoremediation of soils contaminated by organic chemicals is a challenging problem in environmental science and engineering. On the basis of identifying remediation plants from ornamentals, the remediation capability of Mirabilis Jalapa L. to treat petroleum contaminated soil from the Shengli Oil Field in Dongying City, Shandong Province, China was further investigated using a field plot experiment carried out in a greenhouse. The results showed that the average efficiency of removing total petroleum hydrocarbons (TPHs) by M. jalapa over the 127-day culture period was high, up to 41.61-63.20%, when the removal rate by natural attenuation was only 19.75-37.92%. The maximum reduction occurred in the saturated hydrocarbon fraction compared with other components of petroleum contaminants. According to the qualitative and quantitative parameters including plant height, fresh weight, dry weight, root length, root weight and visual stress symptoms, it was indicated that M. jalapa had a peculiar tolerance to petroleum contamination and could effectively promote the degradation of TPHs when the concentration of petroleum hydrocarbons in soil was equal to and lower than 10,000 mg/kg. The population of living microorganisms in the planted soil could be also adaptive to