Biodegradation of Diesel oil by Rhodococcus sp. Strain SeAG1

The occurrence of diesel oil contamination in Malaysia’s environment is very common. Many come from accidental spillage during extraction and transportation. The oil contains high levels of persistent hydrocarbons which can negatively influence the ecosystems. The use of microorganisms for the biodegradation of hydrocarbons present in the diesel oil has been suggested as the best approach for the elimination of diesel oil from the environment because this method is very cost effective and safe. To date, there are very few studies on bacteria that possess the ability to survive in high concentrations of hydrocarbons, salt, heavy metals and pesticides. Therefore the isolation and characterization of a potential diesel oil-degrading bacterium from hydrocarbon contaminated sites is crucial in this research. The technique on cell immobilization was employed to evaluate the efficiency of entrapped cells as well as the effect on shielding the cells from high levels of hydrocarbons, metals and pesticides. A total of six isolates was obtained from 50 sample sites contaminated with hydrocarbon. Isolate P2C, the best diesel oil-degrading bacterium was isolated from a hydrocarbon contaminated soil from Pulau Pangkor. 16S rRNA gene analysis, show that Isolate P2C has high similarity to Rhodococcus sp., and was designated as Rhodococcus sp. strain SeAG1. This bacterium exhibited optimum growth and diesel oil degradation at 30oC in the medium containing 10% (v/v) diesel oil, and was able to degrade 64.4% of diesel oil after 30 days of incubation. The optimum nitrogen source was sodium nitrate (NaNO3) at 0.7% (w/v). The optimum pH for bacterial growth and diesel oil degradation was pH 7.5 using phosphate buffer. Rhodococcus sp. strain SeAG1 was then immobilized in gellan gum using optimized parameters. The optimized parameters for cell immobilization were; 4 mm bead size; 250 bead/100 ml for initial cell loading; 0.75 % (v/w) of gellan gum with addition of 7% (v/v) hexadecane. Degradation of diesel oil using freely-suspended cells and immobilized cell was monitored weekly by using gas chromatography equipped with flame ionization detector (GC-FID). The free cells of strain SeAG1 can resist up to 50% (v/v) diesel oil with 5.4% of degradation compared to immobilized cells can degrade 50% (v/v) of diesel oil up to 23.6%, which was the maximum concentration tested in this study within 30 days. The effects of various salinity, heavy metals and pesticides on the degradation of diesel oil were tested for both on free and immobilized cells. Based on the results obtained, immobilized cell can resist higher concentrations of diesel oil and exhibited a higher degradation rate compared to free cells. Free cells can only tolerate up to 5% (w/v) salinity, while immobilized cells can withstand up to 10% (w/v) salinity. Chromium (Cr), Argentum (Ag) and Mercury (Hg) decreased diesel oil degradation in free cells but the effect was much lower on the immobilized cells. Similar results were obtained for pesticides where 3 of the tested pesticides which is carbofuran, paraquat dichloride and atrazine. This compound slightly lowered diesel oil degradation activity by free cells and none of the tested pesticides lowered diesel oil degradation activity by immobilized cells. Therefore the immobilization method has been proven to be an effective system for the bioremediation of diesel oil compared to free cells

Synthesis of protocatechuic acid–zinc/aluminium–layered double hydroxide nanocomposite as an anticancer nanodelivery system

Protocatechuic acid, an active anticancer agent, has been intercalated into Zn/Al–layered double hydroxide at Zn/Al=2) using two different preparation methods, co-precipitation and ion-exchange, which are labelled as PZAE and PZAC, respectively. The release of protocatechuate from the nanocomposites occurred in a controlled manner and was fitted satisfactorily to pseudo-second order kinetics. The basal spacing of the resulting nanocomposites PZAE and PZAC was 10.2 and 11.0 Å, respectively, indicating successful intercalation of protocatechuate anions into the interlayer galleries of Zn/Al–NO3–LDH in a monolayer arrangement with angles of 24 and 33° from the z-axis in PZAE and PZAC, respectively. The formation of nanocomposites was further confirmed by a Fourier transform infrared study. Thermogravimetric and differential thermogravimetric analyses indicated that the thermal stability of the intercalated protocatechuic acid was significantly enhanced compared to its free protocatechuic acid, and the drug content in the nanocomposites was estimated to be approximately 32.6% in PZAE and 29.2% in PZAC. Both PZAE and PZAC nanocomposites inhibit the growth of human cervical, liver and colorectal cancer cell lines and exhibit no toxic effects towards normal fibroblast 3T3 cell after 72 h of treatment

In vitro anti-cancer effect of layered double hydroxide-chlorogenic acid nanoparticles as drug delivery system

Layered double hydroxides (LDHs) have obtained significant attention as nano-sized carriers for therapeutic and bio-active molecules. LDH nanoparticles are competent for drug delivery purposes due to their numerous advantageous properties such as unique structure, high anionic exchangeability and solubility in acidic media which give rise to the controlled release of intercalated molecules. Hence, the aim of this study is to investigate the properties of newly constructed drug delivery system consisting a natural compound, chlorogenic acid (CA) intercalated into Zn/Al-LDH interlayers for the formation of the nanocomposite. Structural and physical properties of chlorogenic acid intercalated into Zn/Al-LDH (CA-Zn/Al-LDH) were determined by X-ray diffraction, field emission scanning and transmission electron microscope. Loading efficiency of CA in between the interlayers of Zn/Al-LDH was investigated using a UV-Vis spectrophotometer. Subsequently for in vitro work, the anti-cancer properties of CA-Zn/Al-LDH nanocomposite on various cancer and normal cell lines were carried out using 3-(4,5-dimethylthiazol 2-yl)-2,5-diphenyl bromide (MTT) reduction assay. Half-maximal inhibitory concentrations of CA-Zn/Al-LDH in all the cell lines was found to be ranged from 0-50 μg/L, determined after 24, 48 and 72 h. To justify their efficacy, apoptosis induction and clonogenic inhibition of chlorogenic acid-LDH nanocomposite were observed and analyzed microscopically. The preliminary result of this study may offer valuable primary information towards the development of potential nanodrugs for cancer therapy

Protocatechuic acid-zinc/aluminium layered double hydroxide nanocomposite as an anticancer nanodelivery system

Protocatechuic acid, an anticancer agent has been intercalated into Zn/Al-layered double hydroxide at Zn to Al molar ratio of 2 using two different preparation methods; co-precipitation and ion-exchange and labeled as PZAE and PZAC, respectively. The release of the anion, protocatechuate from both of the nanocomposites occurred in a controlled manner governed by pseudo-second order kinetics. The basal spacing of resulting nanocomposites PZAE and PZAC was 10.2 and 11.0 Å, respectively, indicating successful intercalation of protocatechuate anions into the interlayer galleries of Zn/Al-LDH in monolayer arrangement with an angle of 24 and 33° from z axis for PZAE and PZAC, respectively. The formation of the nanocomposites was confirmed by Fourier transform infrared study and surface area analysis showed that the nanocomposites are of mesoporous-type material. The thermal stability of the intercalated protocatechuic acid significantly enhanced compared to its counterpart, free protocatechuic acid. The drug loading in the nanocomposites was estimated to be about 32.6% in PZAE and 29.2% in PZAC. Both PZAE and PZAC nanocomposites inhibit the growth of human cervical (HeLa), liver (HepG2) and colorectal (HT29) cancer cell lines and show no toxic effect towards normal fibroblast 3T3 cell after 72 hours of treatment

Anticancer nanodelivery system with controlled release property based on protocatechuate–zinc layered hydroxide nanohybrid

Background: We characterize a novel nanocomposite that acts as an efficient anticancer agent. Methods: This nanocomposite consists of zinc layered hydroxide intercalated with protocatechuate (an anionic form of protocatechuic acid), that has been synthesized using a direct method with zinc oxide and protocatechuic acid as precursors. Results: The resulting protocatechuic acid nanocomposite (PAN) showed a basal spacing of 12.7 Å, indicating that protocatechuate was intercalated in a monolayer arrangement, with an angle of 54° from the Z-axis between the interlayers of the zinc layered hydroxide, and an estimated drug loading of about 35.7%. PAN exhibited the properties of a mesoporous type material, with greatly enhanced thermal stability of protocatechuate as compared to its free counterpart. The presence of protocatechuate in the interlayers of the zinc layered hydroxide was further supported by Fourier transform infrared spectroscopy. Protocatechuate was released from PAN in a slow and sustained manner. This mechanism of release was well represented by a pseudo-second order kinetics model. PAN has shown increased cytotoxicity compared to the free form of protocatechuic acid in all cancer cell lines tested. Tumor growth suppression was extensive, particularly in HepG2 and HT29 cell lines. Conclusion: PAN is suitable for use as a controlled release formulation, and our in vitro evidence indicates that PAN is an effective anticancer agent. PAN may have potential as a chemotherapeutic drug for human cancer

Biocompatible polymers coated on carboxylated nanotubes functionalized with betulinic acid for effective drug delivery

Chemically functionalized carbon nanotubes are highly suitable and promising materials for potential biomedical applications like drug delivery due to their distinct physico-chemical characteristics and unique architecture. However, they are often associated with problems like insoluble in physiological environment and cytotoxicity issue due to impurities and catalyst residues contained in the nanotubes. On the other hand, surface coating agents play an essential role in preventing the nanoparticles from excessive agglomeration as well as providing good water dispersibility by replacing the hydrophobic surfaces of nanoparticles with hydrophilic moieties. Therefore, we have prepared four types of biopolymer-coated single walled carbon nanotubes systems functionalized with anticancer drug, betulinic acid in the presence of Tween 20, Tween 80, polyethylene glycol and chitosan as a comparative study. The Fourier transform infrared spectroscopy studies confirm the bonding of the coating molecules with the SWBA and these results were further supported by Raman spectroscopy. All chemically coated samples were found to release the drug in a slow, sustained and prolonged fashion compared to the uncoated ones, with the best fit to pseudo-second order kinetic model. The cytotoxic effects of the synthesized samples were evaluated in mouse embryonic fibroblast cells (3T3) at 24, 48 and 72 h. The in vitro results reveal that the cytotoxicity of the samples were dependent upon the drug release profiles as well as the chemical components of the surface coating agents. In general, the initial burst, drug release pattern and cytotoxicity could be well-controlled by carefully selecting the desired materials to suit different therapeutic applications

Identification of marine bacteria isolated from marine soil sediments and their ability to biosynthesise AgNPs extracellularly

Over the past few years, nanoparticles synthesis is one of the most active research in the nanotechnology field. The synthesis can be done chemically, physically and biologically. However, some researchers prefer to synthesise it biologically or also known as biosynthesis or ‘green synthesis’ because it is believed to be safer, environmentally friendly and cost-effective. In this work, we report the extracellular synthesis of 20 isolated marine bacteria from marine soil sediment which were identified and evaluated to synthesise silver nanoparticles (AgNPs). This was done by the addition of silver nitrate (AgNO3) solution with the cell-free supernatant of the isolated marine bacteria at room temperature. The marine bacteria were identified using 16S rRNA identification and neighbour-joining phylogenetic tree were constructed. Identification results showed that the isolated bacteria consist of 19 Serratia sp. and 1 Providencia sp. The biosynthesised AgNPs colloids were evaluated using morphological and optical analysis. AgNPs were observed for colour change and determined using ultraviolet-visible (UV-Vis) spectrophotometer. The existence of surface plasmon resonance peak at 400 to 450 nm is evidence of AgNPs formation

The mechanistic action of biosynthesised silver nanoparticles and its application in aquaculture and livestock industries

Nanotechnology is a rapidly developing field due to the emergence of various resistant pathogens and the failure of commercial methods of treatment. AgNPs have emerged as one of the best nanotechnology metal nanoparticles due to their large surface-to-volume ratio and success and efficiency in combating various pathogens over the years, with the biological method of synthesis being the most effective and environmentally friendly method. The primary mode of action of AgNPs against pathogens are via their cytotoxicity, which is influenced by the size and shape of the nanoparticles. The cytotoxicity of the AgNPs gives rise to various theorized mechanisms of action of AgNPs against pathogens such as activation of reactive oxygen species, attachment to cellular membranes, intracellular damage and inducing the viable but non-culturable state (VBNC) of pathogens. This review will be centred on the various theorized mechanisms of actions and its application in the aquaculture, livestock and poultry industries. The application of AgNPs in aquaculture is focused around water treatment, disease control and aquatic nutrition, and in the livestock application it is focused on livestock and poultry

Optimization of ultrasonic-assisted extraction of phenolic compound from golden chicken fern (Cibotium barometz) rhizome via response surface methodology

There are a lot of medical potentials from Cibotium Barometz that can be exploited due to its secondary metabolites, specifically the phenolic compounds. Therefore, numerous studies have been employed to study the optimization of phenolic compounds extraction from other medical beneficial plants. However, until today there are no definite experiment has been conducted to study the optimization of phenolic compounds extraction of C. Barometz. Hence, this study was designed to systemically optimize the extraction process of phenolic compounds from C. Barometz by using response surface methodology (RSM). The variables were evaluated by using three-factor Box-Behnken experimental design. The three process variables were; ethanol concentration (20-100%), extraction time (10-60 min) and solid-to-liquid ratio (1:20 - 1:100; g: mL) while the independent variable is the total phenolic content (TPC). The optimum extraction condition obtained from RSM are 38.99% ethanol concentration, 47.51 min extraction time, and 1:59.68 (g: mL) ratio under ultrasonic assisted extraction (UAE). Net antioxidant activity was determined by scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, where the lowest IC50 obtained was from ethanol extract via RSM approach (IC50 value 817.87±23.75 μg/mL) which values lie within the range of standard error of the standard (IC50 value 242.53±22.76 μg/mL). The results show that the extraction of C. Barometz can be systemically optimized by using the variables obtained from the RSM method