Desulfotomaculum copahuensis strain CINDEFI1 is a novel spore-forming sulfate-reducing bacterium isolated from the Copahue volcano area, Argentina. Here, we present its draft genome in which we found genes related with the anaerobic respiration of sulfur compounds similar to those present in the Copahue environment.
New solid acid catalyst consisting of zirconium sulfate (ZS) supported on a pure-HMS hexagonal mesoporous material (HMS) have been prepared and characterized. This heterogeneous catalyst is able to make a contribution to the field of acid catalyst involving bulky organic molecules. XRD analysis shows that ZS is intact after impregnated on HMS surface and formed finely dispersed species. No ZS crystal phase was developed even at ZS loadings as high as 40 wt %. The occurrence of chemical interaction between ZS and HMS was observed by XPS analysis. Further, XRF results demonstrated that there is no leaching of ZS elements after impregnation. This study shows that ZS can be impregnated on HMS and would be a promising solid acid catalyst for acid-type reactions espcially invovling bulky organic molecuels.
Concrete durability determines service life of structures. It can though, be weakened by aggressive environmental conditions. For instance, bio-corrosion process is due to the presence and activity of microorganisms which produce sulphuric acid to form sulphate deterioration of concrete materials. The problems related to durability and repair systems are due to lack of suitable concrete materials. The use bacteria for concrete repairing and plugging of pores and cracking in concrete has been recently explored. Previous studies had proved the possibility of using specific bacteria via bio concrete as a sustainable method for improving concrete properties. Thus, lack of information on the application of bio concrete exposed to extreme condition was the motivation for this research.
The objective of this research was to determine the durability of an engineered cementitious composite (ECC) incorporating crumb rubber (CR) and graphene oxide (GO) with respect to resistance to acid and sulphate attacks. To obtain the mix designs used for this study, response surface methodology (RSM) was utilized, which yielded the composition of 13 mixes containing two variables (crumb rubber and graphene oxide). The crumb rubber had a percentage range of 0-10%, whereas the graphene oxide was tested in the range of 0.01-0.05% by volume. Three types of laboratory tests were used in this study, namely a compressive test, an acid attack test to study its durability against an acidic environment, and a sulphate attack test to examine the length change while exposed to a sulphate solution. Response surface methodology helped develop predictive responsive models and multiple objectives that aided in the optimization of results obtained from the experiments. Furthermore, a rubberized engineered cementitious composite incorporating graphene oxide yielded better chemical attack results compared to those of a normal rubberized engineered cementitious composite. In conclusion, nano-graphene in the form of graphene oxide has the ability to enhance the properties and overcome the limitations of crumb rubber incorporated into an engineered cementitious composite. The optimal mix was attained with 10% crumb rubber and 0.01 graphene oxide that achieved 43.6 MPa compressive strength, 29.4% weight loss, and 2.19% expansion. The addition of GO enhances the performance of rubberized ECC, contributing to less weight loss due to the deterioration of acidic media on the ECC. It also contributes to better resistance to changes in the length of the rubberized ECC samples.
In this study, a novel glyphosate-degrading shows the ability to reduce molybdenum to
molybdenum blue. The enzyme from this bacterium was partially purified and partially
characterized to ascertain whether the Mo-reducing enzyme from this bacterium shows better or
lower efficiency in reducing molybdenum compared to other Mo-reducing bacterium that only
exhibits a single biotransformation activity. The enzyme was partially purified using ammonium
sulphate fractionation. The Vmax for the electron donating substrate or NADH was at 1.905 nmole
Mo blue/min while the Km was 6.146 mM. The regression coefficient was 0.98. Comparative
assessment with the previously characterized Mo-reducing enzyme from various bacteria showed
that the Mo-reducing enzyme from Burkholderia vietnamiensis strain AQ5-12 showed a lower
enzyme activity.
This study involves extraction of sulfated polysaccahride (SP) from brown seaweed (Turbinaria turbinata). Eight processing conditions affecting enzyme aided extraction (EAE) were screened using Plackett-Burman design. Three significant factors (hydrolysis time, enzyme concentration and extraction stage) were optimized using Faced Centred Central Composite Design in Random Surface Methods. Micrograph obtained using Field Emission Scanning Electron Microscopy revealed that cellulase degradation ruptured the seaweed cell matrix thus caused increase in the release of SP. The optimum conditions for extraction of SP from T. turbinata are: extraction stage of 2, hydrolysis time of 19.5 h and enzyme concentration of 1.5 μl/ml to produce 25.13% yield. The SP obtained from cellulase treated T. turbinata is a suitable anti-inflammatory agent for pharmaceutical applications.
Acid sulfate soil characterized by pyrite (FeS2) which produces high acidity (soil pH < 3.5) and release high amount of Al3+ and Fe2+. Application of 4 t ha-1 Ground Magnesium Limestone (GML), is a common rate used for acid sulfate soil by the rice farmers in Malaysia. Therefore, this study was conducted to evaluate the integral effect of ground magnesium limestone (GML) and calcium silicate and to determine the optimal combination on acid sulfate soils in Malaysia. The acid sulfate soils were incubated under the submerged condition for 120 days with GML (0, 2, 4, 6 t ha-1) in combination with calcium silicate (0, 1, 2, 3 t ha-1) arranged in a Completely Randomized Design (CRD). The soil was sampled after 30, 60, 90 and 120 days of incubation and analyzed for soil pH, exchangeable Al, Ca, Mg, K and available Si. A total of 2 out of 16 combinations met the desired soil requirement for rice cultivation. The desired chemical soil characteristics for rice cultivation are soil pH > 4, exchangeable Al < 2 cmolc Kg-1, exchangeable Ca > 2 cmolc kg-1, exchangeable Mg > 1 cmolc kg-1 and Si content > 43 mg kg-1. The combinations are i) 2 t ha-1 calcium silicate + 2 t ha-1 GML, and ii) 3 t ha-1 calcium silicate + 2 t ha-1 GML, respectively. These combination rates met the desired requirement of soil chemical characteristics for rice cultivation. Soil acidity was reduced by a gradual release of Ca2+ and SiO32- from calcium silicate continuously filling the exchange sites and reducing the potential of extra (free) H+ availability in the soil system. Combination of calcium silicate and GML, shows the ameliorative effect with; i) release of Ca, ii) binding of Al3+ making it inert Al-hydroxides and, iii) bind H+ to produce water molecules.
A co-deposition of nickel-phosphorus-alumina (NiPA) composite coatings were obtained from an ordinary sulphate-based plating bath consisting of 5 g/l alumina (Al2O3) particles. The particles were dispersed by using mechanical agitation at 125 rpm. The presence of Ni3P and Al2O3 phases in the coatings was confirmed by XRD analysis. SEM/EDX results indicated that a smooth Ni3P coating was obtained and Al2O3 particles were embedded into the coating. Microscopic observation showed that the bonding between the Ni3P metal matrix and the Al2O3 ceramic particles was compact.
Air pollution can be detected through rainwater composition. In this study, long-term measurements (2000-2014) of wet deposition were made to evaluate the physicochemical interaction and the potential sources of pollution due to changes of land use. The rainwater samples were obtained from an urban site in Kuala Lumpur and a highland-rural site in the middle of Peninsular Malaysia. The compositions of rainwater were obtained from the Malaysian Meteorological Department. The results showed that the urban site experienced more acidity in rainwater (avg=277mm, range of 13.8 to 841mm; pH=4.37) than the rural background site (avg=245mm, range of 2.90 to 598mm; pH=4.97) due to higher anthropogenic input of acid precursors. The enrichment factor (EF) analysis showed that at both sites, SO42-, Ca2+ and K+ were less sensitive to seawater but were greatly influenced by soil dust. NH4+ and Ca2+ can neutralise a larger fraction of the available acid ions in the rainwater at the urban and rural background sites. However, acidifying potential was dominant at urban site compared to rural site. Source-receptor relationship via positive matrix factorisation (PMF 5.0) revealed four similar major sources at both sites with a large variation of the contribution proportions. For urban, the major sources influence on the rainwater chemistry were in the order of secondary nitrates and sulfates>ammonium-rich/agricultural farming>soil components>marine sea salt and biomass burning, while at the background site the order was secondary nitrates and sulfates>marine sea salt and biomass burning=soil components>ammonia-rich/agricultural farming. The long-term trend showed that anthropogenic activities and land use changes have greatly altered the rainwater compositions in the urban environment while the seasonality strongly affected the contribution of sources in the background environment.
Acid sulfate soils are generally not suitable for the crop production unless they are efficiently improved. A study was conducted to improve the productivity of acid sulfate soils for rice cultivation using ground magnesium limestone (GML), basalt and organic fertilizer. The study was conducted on rice in laboratory, glasshouse and field. The pH of acid sulfate soils was low and exchangeable Al was very high which affected rice growth. The application of GML and basalt increased soil pH and reduced Al toxicity. GML required to ameliorate the soils for rice cultivation was 4 t ha-1. Basalt in combination with organic fertilizer was a good soil amendment, but required to be applied a few months ahead of rice cultivation. Due to GML or basalt application, rice plants grew well even though water pH was below 5. The highest rice yield obtained was 4.0 t ha-1 season-1 for Sulfaquepts and it was 7.5 t ha-1 season-1 for Sulfosaprists. In general, the application of GML or basalt in combination with organic fertilizer improved the productivity of acid sulfate soils and consequently enhanced rice yield.
The ceaseless increase of pollution cases due to the tremendous consumption of fossil fuels has steered the world towards an environmental crisis and necessitated urgency to curtail noxious sulfur oxide emissions. Since the world is moving toward green chemistry, a fuel desulfurization process driven by clean technology is of paramount significance in the field of environmental remediation. Among the novel desulfurization techniques, the oxidative desulfurization (ODS) process has been intensively studied and is highlighted as the rising star to effectuate sulfur-free fuels due to its mild reaction conditions and remarkable desulfurization performances in the past decade. This critical review emphasizes the latest advances in thermal catalytic ODS and photocatalytic ODS related to the design and synthesis routes of myriad materials. This encompasses the engineering of metal oxides, ionic liquids, deep eutectic solvents, polyoxometalates, metal-organic frameworks, metal-free materials and their hybrids in the customization of advantageous properties in terms of morphology, topography, composition and electronic states. The essential connection between catalyst characteristics and performances in ODS will be critically discussed along with corresponding reaction mechanisms to provide thorough insight for shaping future research directions. The impacts of oxidant type, solvent type, temperature and other pivotal factors on the effectiveness of ODS are outlined. Finally, a summary of confronted challenges and future outlooks in the journey to ODS application is presented.