Papers by Keyword: Bacteria

Abstract: The oily sludge at the South Refineries firm in Basrah Governorate, Southern Iraq, was treated with biosurfactant made from native bacterial isolates. Consequently, 33 bacterial isolates were obtained from 11 samples of oily sludge, water, and soil obtained from various locations within the organization. These isolates were identified biochemically using the VITEK II system and genetically using 16sRNA. The bacterial species identified by the findings were Bacillus cereus, Aeromonas hydrophila/caviae, Staphylococcus lentus, and S. pseudointermedius. The biosurfactant was manufactured by selecting one isolate from each species. The bacteria and their biosurfactants showed a remarkable ability to break down oily sludge. Bacillus cereus was able to reduce 99.16% of the aliphatic fraction, and Staphylococcus lentus 99.69% of the aromatic fraction. These findings suggest that these bacteria could be utilized for bioremediation of environments polluted by petrochemical oily sludge, resulting in reduced pollution and increased industrial output.

Abstract: Concrete is one of the most used construction materials worldwide. It is known to be a strong and durable material at a reasonable price. The most well-known problem in concrete is the cracks, which affect the service life of the concrete structures and leads to consumes higher costs through maintenance. Cracks allow penetrating any ions into the concrete resulting in other big problems such as corrosion of steel reinforcement, sulphate attack, carbonation, alkali-aggregate reaction, etc. It is impossible to prevent the formation of cracks, therefore they can be controlled or repaired using a variety of methods. Nowadays, self-healing is one of the widely recognized techniques to improve concrete's long-term durability. Healing agents such as bacteria, chemical compounds, and polymers are utilized. In this method, with the help of a healing agent, the cracks start to heal autonomously during crack formation. Since Bacteria is the most used material for healing concrete, self-healing concrete is also known as bacterial-concrete or bioconcrete. This article provides an overview of self-healing concrete including describing the system, process, durability, and mechanical properties of healed concrete.

Abstract: The spread of disease by bacteria and viruses is very susceptible to outbreaks in public facilities through direct and indirect contact. Indirect contact occurs through intermediate such as housing equipment made of aluminum. One thing that people touch the most is door handles and frames. Aluminum frames are generally anodized to give a color effect because painted directly is difficult. Anodized products generally have a pore structure so that they can easily become an ideal place to grow and colonize bacteria and viruses. To overcome this, the coating process is carried out by electroplating. In this study, aluminum was treated with anodization and non-anodization. The concentration of sulfuric acid solution used was 0.5 M; 1M and 2M. The current used is 0.6A; 0.9A and 1.2M. Increasing the sulfuric acid concentration will increase the efficiency of the cathodic current and increase the mass of the deposit per unit area. Observation of the microstructure with an optical microscope shows the structure formed is dendritic in which the nucleus is continuous. The smooth and flat surface makes aluminum safe to be used and does not become a medium for bacteria or viruses to stick at aluminum surfaces.

Abstract: Silver nanoparticles (Ag⁰) have attracted the most attention due to their broad antimicrobial application and outstanding activity. The silver nanoparticles are usually in colloidal form, then immobilization the colloid onto solid support is still interesting to explore. In this work, a new method for silver colloidal nanoparticle immobilization on silica gel beads (SiG), which was then symbolized as Ag⁰-[chi-SiG] was conducted and characterized successfully. The finding proved that SiG must be coated with three chitosan film layers to give stable support for silver nanoparticles. This coating method caused the chitosan completely covered SiG, and the chitosan film provides coordination bonding for silver ions. The most appropriate solvent for silver ion impregnation on the surface of chi-SiG is methanol compared to other solvents. Tungsten lamp as the photo-irradiation, which is low cost and environmentally friendly has been proven effective for silver ion reduction, as shown by silver metal colloid UV-Vis surface plasmon resonance at 400-700 nm. Ag⁰-[chi-SiG] showed the antibacterial properties of inhibiting the growth Staphylococcus aureus and Escherichia coli; then it provides the potential application for antibacterial filter material. According to the weight comparison between antibacterial standard and Ag content, then Ag0-[chi-SiG] has two and five times higher of exhibiting zone for each bacteria.

Abstract: The increasing resistance of pathogenic bacteria to the pharmaceutical compound could be a very important issue for public health. A sensitive, fast and accurate approaches for bacteria detection are going to be needed to enhance the effectiveness of treatment. This study aimed to develop a colorimetric sensor based on allylamine-conjugated polyacrylic acid and gold nanoparticles (AuNPs- AAm-PAA) for bacteria detection. Allylamine was conjugated to the polyacrylic acid and mixed with the gold colloid to form a self-assembled AuNPs-AAm-PAA. The polymer-modified gold nanoparticles were characterized for the particle size, zeta potential, reversibility using TEM, particle size analyzer, and UV-Vis spectrophotometer, respectively. The system was observed to detect bacteria and observed by the naked eye, UV-Vis spectrophotometer, and TEM. The results showed that AuNPs-PAA-AAm solution showed an absorbance peak at 530 nm, AuNPs particle size of 25.67 nm ± 2.68, and zeta potential -31.4 ± 4.5 mV. Introduction of bacteria into the Au-AAm-PAA solution resulted in a color change from red to purple at concentrations of 6x10⁸ CFU/mL of Staphylococcus aureus and Escherichia coli. TEM analysis revealed the binding of aggregated gold nanoparticles around the outer membrane of bacteria. The sensor system based on conjugated polymer and gold nanoparticles demonstrated a promising way for bacteria detection.

Abstract: Escherichia coli bacteria sensors have been broadly developed broadly to overcome a diarrheal disease caused by Escherichia coli on poor hygienic water. Sensing layer, as a main part of the sensor, contacts directly to the analyte on sensors system. Some materials were costly and harmful to detect bacteria. Potentially, graphene is a natural carbon derivative with some excellence properties; easy synthesis, and biocompatible. Hence, the quality of the SiO₂/graphene sensing layer was conducted through optical, physical, and electrical characterization to analyze biocompatibility, repeatability, and selectivity. The result showed that Escherichia coli bacterial growth was found around SiO₂/graphene after bacterial exposure indicating a biocompatible material. Raman peak also pointed the fingerprint of graphene after 25 times Escherichia coli exposure through G (1584.52 cm^–1) and 2D peak (2701.5 cm^–1) promising as a repeatable material. The ID/IG ratio increased by the time the bacteria exposure times increased indicating a withstand material from defects and or disorders after bacteria exposure. Through I/V meter, the increasing number of Escherichia coli could increase the resistance value of SiO₂/graphene. This sensing layer could detect the presence of Escherichia coli in limit of detection 16 CFU/mL.

Abstract: Poly-(R)-3-hydroxybutyrate (PHB) is a biopolymer that can be synthesized by several microorganisms such as bacteria, yeast, and fungi as secondary metabolites. PHB is produced by bacteria in a medium containing a limited amount of key nutrients such as nitrogen, phosphorus, and magnesium but rich in carbon sources. PHB is a biodegradable plastic that has many applications in the medical and industrial fields. This study aimed to isolate and characterize a biopolymer produced by a bacterium strain isolated from a termite nest in India that was identified by 16S rRNA method as Bacillus thuringiensis TH-01. The biopolymer was produced by growing the bacteria in a high medium overnight at 37 °C in a shaking incubator at 150 rpm, and the resulting biopolymer was extracted with a mixture of chloroform–NaOCl (1:1). The efficiency of biopolymer production was about 10.545% ± 26.125%. Fourier transform infrared analysis gave prominent absorption peaks at 3400 cm⁻¹ (stretching of O–H), 2900 cm⁻¹ (stretching of C–H), 1700 cm⁻¹ (stretching of C=O), 1280 cm⁻¹ (symmetric deformation of C–H), and 1050 cm⁻¹ (stretching of C−O), confirming that the biopolymer is PHB. The thermal stability of PHB granules as was determined by thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) showed that the decomposition temperature and of the polymer were 271.6–310.0 °C and 7.48 J/g respectively, and its crystallinity was about 5.12%.

Abstract: Bacterial can initiate, accelerate, and/or inhibit corrosion processes through a number of different ways, including modification of the localized environment at the metal/solution interface by causing pitting attack. In this work, the effect of temperature on bacteria (P.Aeruginosa sp) growth will be investigated the nature of bacteria before further investigated its corrosion effect on steel wire rope. It is found that the bacteria grew actively at 30°C. The pH value was also changed from 7 to 8. The corrosion rate with the presence of bacteria has been found increased from 9.95 x 10-7 mdy to 4.884 x 10-5 mdy. While corrosion pitting is found directly proportional to the bacterial activity.

Abstract: Cracks affect the durability of concrete by increasing its permeability. Self-healing materials can begin repairing themselves immediately after creating a crack. This is a big advantage of self-healing materials. In this study, effect of self-healing agents based on calcium carbonate precipitation for concrete is monitored for three months. Bacillus pseudofirmus was chosen as a self-healing agent and was tested on old cement pastes. Calcium precipitation was analyzed by scanning electron microscope with Energy-dispersive X-ray spectroscopy. The effect of added spontaneous calcination, culture media, bacteria and Ca²⁺ was monitored.

Abstract: Recycling of optional water source especially greywater and energy recovery from effluent is garnering impetus owing to clean water scarcity and energy crisis. In current work, photocatalytic fuel cell (PFC) utilizing a TiO₂/ZnO/Zn photoanode and a CuO/Cu photocathode was developed for efficient greywater treatment and power generation. The photoelectrodes were measured by field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and photoluminescence (PL) measurements. Using 2 layers of TiO₂/ZnO on Zn film, chemical oxidation demand (COD) removal efficiency had achieved 73% in the UV light-activated PFC system. The electrical generation was concomitantly found, in which the open-circuit voltage (Voc), short-current density (Jsc) and maximum power density (Pmax) were 634 mV, 0.1612 mA cm^-2 and 0.0257 mW cm^-2, respectively. The PFC has also revealed high antibacterial activity towards and Escherichia coli (E. coli), highlighting its potential photocatalytic and antibacterial properties for greywater reused and clean energy production.