Abdallah S. Ali

The research highlights the environmentally sustainable biosynthesis of silver nanoparticles from fresh leaves of the herbal medicinal plant Moringa oleifera. They may have been used as anti-inflammatory, anticancer, and antimicrobial agents. M. oleifera extract both reduces and stabilizes silver nanoparticles (AgNPs). Optimum factors needed for AgNP biosynthesis were studied using a central composite design (CCD) matrix. Ultraviolet-visible (UV–Vis) absorption spectroscopy, transmission electron microscopy, and Fourier-transform infrared spectroscopy were used to confirm and characterize the synthesized AgNPs. The biogenic AgNPs demonstrated substantial antibacterial potential against the pathogenic strains Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Bacillus subtilis. The antioxidant activity of biosynthesized AgNPs with M. oleifera extract increased from 11.96% when the concentration of the extract was 4 mg/mL to 63.79% at a plant concentration of 20 mg/mL. This research provides an easy and cost-effective technique for the production of stable nanoparticles, with an evaluation of their bioactivity.

Biohydrogen has significant feasibility since biological processes are much less energy intensive compared with electrolysis and thermo-chemical processes. It is widely recognized that considerable amounts of hydrogen (H2) can be produced from renewable resources without using energy from fossil fuels. Biological processes and bacterial fermentation are considered as the most environmentally friendly alternatives for satisfying future hydrogen demand. Biohydrogen production from agricultural and agro-industrial solid waste and wastewater is considered as highly advantageous as materials of this kind are abundant, cheap and biodegradable. The combustion of H2 with oxygen produces water as its only product: Unlike other fuels, the combustion of H2 does not produce carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), hydrocarbons or particulate matter (PM). Therefore, hydrogen is an environmentally friendly fuel where endeavors focus on producing specially designed internal combustion engines that can use H2 as fuel. The results showed that laser irradiated inoculum increased biohydrogen production by 1.2 times of the control. Therefore, in this research, it was hypothesized that exposing purple non-sulfur bacterial (PNSB) mix consortium to Helium-Neon red laser for 2 hours increased cell activity and consequently the biohydrogen production from food wastes through photo-fermentation process.

Pimprinine and streptochlorin are indole alkaloids derived from marine or soil microorganisms. In our previous study, they were promising lead compounds due to their potent bioactivity in preventing many phytopathogens, but further structural modifications are required to improve their antifungal activity. In this study, pimprinine and streptochlorin were used as parent structures with the combination strategy of their structural features. Three series of target compounds were designed and synthesized. Subsequent evaluation for antifungal activity against six common phytopathogenic fungi showed that some of thee compounds possessed excellent effects, and this is highlighted by compounds 4a and 5a, displaying 99.9% growth inhibition against Gibberella zeae and Alternaria Leaf Spot under 50 μg/mL, respectively. EC50 values indicated that compounds 4a, 5a, 8c, and 8d were even more active than Azoxystrobin and Boscalid. SAR analysis revealed the relationship between 5-(3′-indolyl)oxazole scaffold and antifungal activity, which provides useful insight into the development of new target molecules. Molecular docking models indicate that compound 4a binds with leucyl-tRNA synthetase in a similar mode as AN2690, offering a perspective on the mode of action for the study of its antifungal activity. These results suggest that compounds 4a and 5a could be regarded as novel and promising antifungal agents against phytopathogens due to their valuable potency.

Environmental concerns and issues are raised regarding Portland cement manufacturing. Besides, mortar and concrete deterioration is a very common problem. Therefore, eco-cement is an efficient alternative to Portland cement. Eco-cement is an environmentally friendly green building-material having self-healing abilities to remediate concrete cracks. In this study, eco-cement was produced from the ash of agricultural crops residues (pyrolysis of rice straw, sawdust of forest residues, and corn stover) which are hypothesized to enhance the binding abilities among the different components of cementitious materials (residues ash, cement, sand, and bacteria) and accelerate the biomineralization process to precipitate calcite and seal the concrete cracks. Through this study, 12 experiments (4 treatments in triplicates) were conducted. The resultant eco-cement was used to prepare mortar cubes which were tested and analyzed. The following engineering properties of the resultant eco-cement mortar cubes were investigated: compressive strength, four point bending test, and water absorption test. The results show that the addition of rice straw ash delivered the highest compressive strength and the highest four-point-bending of eco-cement mortar cubes average of 86.33 kN and 2.18 kN, respectively; and an acceptable water absorption (5.82%) compared to all other treatments. The energy dispersive X-ray (EDX) analysis test results of the rice straw ash, sawdust ash and corn cob ash according to mass% of Si element were 7.55, 0.93 and 3.13 respectively and 0.84%, 0.45% and 0.41% for Al, respectively. It was concluded that the addition of the ash of agricultural crop residues to the cementitious mixture enhances its properties, where the resulting eco-cement is a promising substitute of the conventional Portland cement.

Microalga would be the paramount resource of biodiesel able of satisfying the world requirements for transportation fuels, which could fully replace the petrodiesel. Therefore, the research studies focus on developing novel biodiesel production methods. The present study investigates the effect of monochromatic light such as red light-emitting diodes (LEDs) and He–Ne red laser radiation on the accumulated lipid and the growth of the green microalgae Chlorella sorokiniana. The irradiation of microalgal cells with He–Ne red laser source which has a wavelength of 632.8 nm was hypothesized to enhance the accumulation of lipid inside the algal cells, which ultimately increases the biodiesel production. The photobiostimulating effects of laser irradiation on biodiesel was investigated by irradiating the microalga for a duration of 2 h with 632.8 nm He–Ne red laser source compared with 2 h irradiation with red LEDs and 2 h irradiation with white light (the control). The results showed that the oil content inside the algal cells irradiated with He–Ne red laser was 3.1 times the algal cells irradiated with white light (the control). Similarly, the biodiesel yielded from the algal cells irradiated with He–Ne red laser was 3.1 times the biodiesel yielded from the algal cells irradiated with white light (the control). However, the oil content and the biodiesel yield from algal cells irradiated with red LEDs were only 0.82 times those of the control. Therefore, it was concluded that the irradiation of microalga with red laser increases the biodiesel yield.

Antibiotic resistance is a global problem; especially the multidrug-resistant bacteria are a serious and fatal problem in the intensive care unit. Interestingly, biosynthesized silver nanoparticles are the promising key to eliminate these microbes. Using Pseudomonas aeruginosa supernatant is an easy and cheap method in silver nanoparticle biosynthesis. The biosynthesis conditions were adjusted, and the profiling of the biosynthesized silver nanoparticles was confirmed.

A strain of Bacillus cereus was isolated from the Saudi Red Sea coast and identified based on culture features, biochemical characteristics, and phylogenetic analysis of 16S rRNA sequences. EPSR3 was a major fraction of exopolysaccharides (EPS) containing no sulfate and had uronic acid (28.7%). The monosaccharide composition of these fractions is composed of glucose, galacturonic acid, and arabinose with a molar ratio of 2.0: 0.8: 1.0, respectively. EPSR3 was subjected to antioxidant, antitumor, and anti-inflammatory activities. The results revealed that the whole antioxidant activity was 90.4 ± 1.6% at 1500 µg/mL after 120 min. So, the IC50 value against DPPH radical found about 500 µg/mL after 60 min. While using H2O2, the scavenging activity was 75.1 ± 1.9% at 1500 µg/mL after 60 min. The IC50 value against H2O2 radical found about 1500 µg/mL after 15 min. EPSR3 anticytotoxic effect on the proliferation of (Bladder carcinoma cell line) (T-24), (human breast carcinoma cell line) (MCF-7), and (human prostate carcinoma cell line) (PC-3) cells. The calculated IC50 for cell line T-24 was 121 ± 4.1 µg/mL, while the IC50 for cell line MCF-7 was 55.7 ± 2.3 µg/mL, and PC-3 was 61.4 ± 2.6 µg/mL. Anti-inflammatory activity was determined for EPSR3 using different methods as Lipoxygenase (LOX) inhibitory assay gave IC50 12.9 ± 1.3 µg/mL. While cyclooxygenase (COX-2) inhibitory test showed 29.6 ± 0.89 µg /mL. EPSR3 showed potent inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci. The exposure times of EPSR3 for the complete inhibition of cell viability of methicillin resistant S. aureus was found to be 5% at 60 min. Membrane stabilization inhibitory gave 35.4 ± 0.67 µg/mL. EPSR3 has antitumor activity with a reasonable margin of safety. The antitumor activity of EPSR3 may be attributed to its content from uronic acids with potential for cellular antioxidant and anticancer functional properties.

The effects of a multistrain potential probiotic (Protexin®), acids, and a bacterin from multidrug-resistant E. coli O26, O78, S. Enteritidis (1,9,12 g.m1,7), and S. Typhimurium (1,4,5,12.i.1,2) on the immune response, haematological parameters, cytokines, and growth parameters of broiler chickens challenged with bacterin live serotypes were investigated. Two experiments were designed using 300 one-day-old chicks (Arbor Acres) randomly assigned to 15 groups. The first experiment comprised 9 groups, including positive and negative control groups and other groups received Protexin®, acids, and the bacterin (0.2 ml/SC), either alone or in combination, on the 1st day. The second experiment contained 6 groups, including positive and negative control groups and other groups received a combination of Protexin®, acids, and the bacterin (0.5 ml/SC) on the 8th day. All the groups except the negative control groups were challenged on the 8th and 16th days in both experiments, respectively, with mixed live bacterin serotypes. The groups that received Protexin®, acids, and the bacterin either alone or in combination revealed significant improvements in the immune response to the bacterin (p ≤ 0.05). The groups in the 1st experiment and most the 2nd experiment groups showed a reduced mortality rate and decreased levels IFN-γ, IL-4, and IL-12 cytokines (p ≤ 0.05). Moreover, these groups demonstrated increases in haematological parameters and reduced rates of infection-caused anaemia. These groups showed significant increases in growth performance parameters, such as body weight, weight gain, and the feed conversion ratio (FCR) (p ≤ 0.05). There was a beneficial effect on 1-day-old chickens produced by combining Protexin®, acids, and the bacterin (0.2 ml/SC).

The microbial fuel cells (MFCs) are biochemical devices in which bacteria create electrical power by oxidizing simple compounds such as glucose as well as complex organic matter in wastewater. In this study, pumping air into the cathode chamber and its effect on microbial fuel cell performance was investigated. The metabolism of bacteria existed in wastewater was responsible for the generation of bioelectricity. The developed MFC system was designed by utilizing phosphate buffer to operate the system at controlled pH equal 7 and at a stable temperature of 30oC. It was found that increasing oxygen supply to the cathode chamber has a positive effect on the cell performance by increasing the voltage value. Generally, the efficiency of microbial fuel cell was enhanced in the case of cathodic chamber aeration in comparison to the case of no aeration was applied. It was found that the voltage increased in the case of oxygen supply to reach 0.45 mv with a stability over the 138 h of the experiment compared to the case of no aeration was applied where the voltage reached only 0.2 mV with stability in one case and 0.4 mV after 78 h of operation with instability in the second case. Therefore, the performance of the microbial fuel cell improved. It can be concluded that oxygen concentration affects both reaction kinetics and final power efficiency.

At present, the major body of research is focused on weaning the world from fossil fuels. The problem is that the world is running out of fossil fuel. Therefore, an alternative source must be identified. The biofuels are promising alternatives. In the case of petrodiesel, a promising alternative is biodiesel production from algae. The ability of microalgae to generate large quantities of lipids with a fast growth rate made them superior biodiesel producers. Using light-emitting diodes (LEDs) as an energy source in microalgal cultivation was recently increased owing to its large spectrum, endurance, and low-energy utilization. Changes in cultivation conditions, limited capabilities of harvesting light, and self-shading of microalgae were the most important problems. Therefore, the photobiostimulation of algae using LEDs radiation led to an increase in algal growth rate which results in increased lipid production. This research investigated the influence of monochromatic LEDs on the growth of Chlorella sorokiniana microalga. At the first phase, microalgae growth and algal biomass significantly increased under red LEDs [2.3 g/L], blue LEDs [1.8 g/L], green LEDs [0.7 g/L], and white LEDs (0.6) g/L as a control, respectively. At the second phase, microalgal growth and algal biomass significantly increased under red LEDs [2.9 g/L], blue LEDs 2.3 g/L, and white LEDs (1.5) g/L as a control, respectively. The percentage of extracted oil (%) or the yield of extracted oil of microalgae was 10.38 % (white LEDs), 16.94 % (blue LEDs), and 15.55 % (red LEDs) respectively. It was concluded that the photobiostimulation of algae using LEDs led to the enhanced weight of algal biomass, therefore increased of lipids and biodiesel production. The red LEDs were the best one in terms of increasing the weight of algal biomass. The blue LEDs were the best one in terms of increasing the percentage of extracted oil. However, the green LEDs were not effective.

Streptochlorin is a small molecule of indole alkaloid isolated from marine Streptomyces sp., it is a promising lead compound due to its potent bioactivity in preventing many phytopathogens in our previous study, but further structural modifications are required to improve its antifungal activity. Our work in this paper focused on the replacement of oxazole ring in streptochlorin with the imidazole ring, to discover novel analogues. Based on this design strategy, three series of streptochlorin analogues were efficiently synthesized through sequential Vilsmeier-Haack reaction, Van Leusen imidazole synthesis and halogenation reaction. Some of the analogues displayed excellent activity in the primary assays, and this is highlighted by compounds 4g and 4i, the growth inhibition against Alternaria Leaf Spot and Rhizoctorzia solani under 50 μg/mL are 97.5% and 90.3%, respectively, even more active than those of streptochlorin, pimprinine and Osthole. Molecular docking models indicated that streptochlorin binds with Thermus thermophiles Leucyl-tRNA Synthetase in a similar mode to AN2690, offering a perspective on the mode of action study for antifungal activities of streptochlorin derivatives. Further study is still ongoing with the aim of discovering synthetic analogues, with improved antifungal activity and clear mode of action.

Recent advancement was the use of laser radiation to photobiostimulate the methanogenic bacteria in order to increase the biogas and methane production from the anaerobic digestion (AD) of livestock manure. However, the environmental impact of using the laser radiation as anaerobic bacteria stimulator still not evaluated. The objective of this paper is to conduct a comparative environmental impact evaluation of manure treatment with different laser radiation times for biogas production. A life-cycle assessment (LCA) methodology was implemented for this purpose. The treatments under evaluation were 0.5 h, 1h and 2 h of laser irradiation compared to 1 h incandescent lighting and the control (neither laser irradiation nor light was used). The highest biogas yield, methane content and overall Energy were achieved with 0.5 h laser irradiation and were 335251 m3, 63.1% and 2043353 kWh, respectively. The results were presented in the form of the specific impacts on global warming and greenhouse gas (GHG) emissions mitigation of producing and utilizing biogas as an energy source. It was concluded that the photobiostimulation of anaerobic bacteria using laser irradiation has no negative environmental impact compared to the control, where no irradiation was applied.

In the present study, juice of water hyacinth (Eichhorina crassipes), either crude or from its successive dilutions (1:1, 1:10, 1:30, 1:50 v/v) supported the in vitro development of Bacillus megaterium, Bacillus subtilis, Azotobacter chroococcum and Rhizobium leguminosarum biovar Phaseoli with doubling time (23.1–63.0 min) which was comparable if not shorter, to that calculated using the standard laboratory -synthetic media (nutrient, N-deficient mannitol and yeast extract agar media; 48.0–64.8 min). Rhizospheric microorganisms of legume and non-legume plants successfully grew on surface-inoculated agar plates of crude and diluted juices of the macrophyte. Tea bags filled with the dehydrated powders (5 and 10 g l−1) of water hyacinth supported the in situ recoverability of total rhizobacteria in population densities (3 × 107 - >108 cfu.g−1), which were found to be comparable, if not excessive, to those enumerated on the recommended culture media. Morpho-physiological identification of some isolates that had developed on the plant juice and tea bag culture media, revealed that they are not akin to those cultured on the chemically-synthetic culture media; they possibly represent a portion of recommended media - unculturables.

This literature review discusses several aspects of biodiesel production from microalgae. This paper elucidates the optimal bioenvironmental conditions for microalgae cultivation, process design of algal biodiesel production, physicochemical properties of lipids extracted from microalgae and the properties of the produced biodiesel fuel, and the transesterification process. On the other hand, this paper illustrates the designs of up-to-date full-scale and lab-scale photobioreactors (PBRs). Furthermore, this paper argues different bioengineering aspects of biodiesel production from microalgae. Eventually, the measurements, calculations, design parameters, Life Cycle Analysis (LCA) of the production process are discussed.