The study aimed to optimize the treatment of oil refinery–contaminated wastewater through modification of the well-established activated sludge process with new nanocomposite (NC) materials to produce high-quality treated effluents for potential reuse. Refinery wastewater samples were collected from one of the major oil refineries, Alexandria, Egypt, where the operation, performance, and efficiency of the current activated sludge (AS) unit were evaluated for 6 consecutive months. Two AS bench scale PVC basins were constructed. Magnetite nanoparticles (Fe₃O₄ NPs) and magnetite silica (Fe₃O₄/silica) nanocomposite (NC) were prepared and characterized. Bioremediation trials were carried out in a sequential batch mode using Fe₃O₄/silica NC–modified AS and control (unmodified AS). The proposed treatment produced high-quality effluents in a very short time (2 h) despite the very high initial pollutant concentration accompanied with a reduction in the produced sludge. The highest removal of TSS, TDS, BOD, COD, and OG from raw industrial wastewater recorded 78.33, 3.6, 87.65, 85.17, and 92.92% compared to 55.3, 12.6, 50.0, 40.22, and 56.84%, respectively, achieved by the unmodified AS unit. The results confirmed that integration of the AS treatment with nanomaterial composite is highly effective, promising, and economic for the treatment of highly toxic and complicated industrial wastewater such as petroleum refinery effluents.

The increasing global demand for petroleum oils has led to a significant increase in their cost and has led to the search for renewable alternative waste resources for biodiesel synthesis and production using novel environmentally sound and acceptable methods. In the current study, Kocuria flava lipase was immobilized on Fe₃O₄/cellulose nanocomposite; and used as a biocatalyst for the conversion of cooking oil wastes into biodiesel through the transesterification/esterification process. The characterization of Fe₃O₄/cellulose nanocomposite revealed several functional groups including carboxyl (C=O) and epoxy (C-O-C) groups that act as multipoint covalent binding sites between the lipase and the Fe₃O₄/cellulose nanocomposite and consequently increasing lipase immobility and stability. The immobilized lipase showed a high thermo-stability as it retained about 70% of its activity at 80 °C after 30 min. The kinetics of immobilized lipase revealed that the K_m and V_max values were 0.02 mM and 32.47 U/mg protein, respectively. Moreover, the immobilized lipase showed high stability and reusability for transesterification/esterification reactions for up to four cycles with a slight decline in the enzyme activity. Furthermore, the produced biodiesel characteristics were compatible with the standards, indicating that the biodiesel obtained is doable and may be utilized in our daily life as a diesel fuel.

This study aims to investigate bacteria for biodegradation of oil pollutants from oily industrial wastewater to be used as bioremediation tools and to determine the characterization of bioremediation bioassays. A screening bioassay was carried out using six exogenous environmental bacterial strains to degrade oily pollution, which indicated promising clearance of the oily wastewater. Two strains, namely Enterobacter cloacae 279-56 (R4) and Pseudomonas otitis MCC10330 (R19), could successfully eliminate oil content and reasonable removal of the organic load. Results showed that the two promising bacterial candidates (R4 and R19) were selected according to the preliminary screening of the six tested bacteria considered the most efficient for all the tested parameters. The highest Removal Efficiency (Removal Efficiency resulted in Residual levels of total dissolved solids (TDS), biochemical oxygen demand, chemical oxygen demand, and Oil content in the treated oily wastewater effluents are 1940, 171, 131, and 84 mg/l respectively where these results are not within safe discharge limits, except for TDS. Hence, the bioremediation assays were carried out using the mixed culture since it was the most efficient strain for degrading all tested parameters.

The current study aimed to investigate the potentiality of yeast isolate Rhodotorula toruloides Y1124 to be used as a feedstock for biodiesel production, and the reutilization of the de-oiled yeast biomass wastes as a biosorbent for the biosorption of Congo red from aquatic solutions was investigated. From screening results, eight yeast isolates were referred to as oleaginous microorganisms, of which yeast isolate Rhodotorula toruloides Y1124 was the highest lipid-accumulating isolate and was used as a feedstock for biodiesel production. The highest lipid accumulation (64.8%) was significantly dependent on the glucose concentration, pH, and incubation temperature according to Plackett–Burman and central composite design results. Under optimized conditions, the estimated amount of biodiesel synthesis from Rhodotorula toruloides biomass represented 82.12% of total analytes. The most prevalent fatty acid methyl esters were hexadecanoic and 11-octadecenoic, comprising 30.04 and 39.36% of total methyl esters which were compatible with plant oils. The optimum biosorption conditions for Congo red removal were pH 6, a 15 min contact time, and an initial dye concentration of 40 mg L⁻¹. The biosorption isothermal and kinetics fitted well with the Langmuir model and the maximal biosorption capacity (q_max) was 81.697 mg g⁻¹. Therefore, the current study may offer a sustainable feedstock with potential viability for both the synthesis of biodiesel and the removal of organic dyes.

Potato peel wastes are generated in high quantities from potato processing industries. They are pollutants to the environment, and they release greenhouse gases into the atmosphere. The present study assessed the potentiality of hydrolyzing potato wastes by amylase-producing fungi to improve biogas generation from potato peels through the anaerobic digestion process. Different fungal isolates were screened for amylase production on potato wastes, and the highest amylase producer was selected for optimizing the efficacy of producing amylases in high quantities to efficiently allow the conversion of potato organic matter into fermentable sugars that are utilized for the anaerobic digestion process. The best amylase producers were those derived from Rhizopus stolonifer (32.61 ± 0.89 U/mL). The highest cumulative methane yield from hydrolyzed potato peel was 65.23 ± 3.9 mL CH₄/g and the methane production rate was 0.39 mL CH₄/h, whereas the highest biogas yield from unhydrolyzed potato wastes was 41.32 ± 2.15 mL CH₄/g and the biogas production rate was 0.25 mL CH₄/h. Furthermore, it was found that the two combined sequential stages of anaerobic digestion (biogas production) followed by biodiesel production (enzymatic esterification) were the most effective, recording 72.36 ± 1.85 mL CH₄/g and 64.82% biodiesel of the total analytes. However, one-pot fermentation revealed that biogas yield was 22.83 ± 2.8 mL CH₄/g and the biodiesel extracted was 23.67% of the total analytes. The insights of the current paper may increase the feasibility of potato peel-based biorefinery through the biological hydrolysis strategy of potato wastes using eco-friendly enzymes.

The poultry gastrointestinal microbiome consists of more than 900 bacterial species and their metabolites; it serves as an indicator of bird health and is influenced by nutrition, medication, and other factors. Dysbiosis is a form of reduced microbial diversity, characterised by the loss of beneficial microbes, the expansion of opportunistic microbes, and the disruption of tight junctions, as well as raised pro-inflammatory cytokines (interleukin-6 and interleukin-17), tumour necrosis factor-α, and Enterobacteriaceae, and decreased short-chain fatty acids. Dysbiosis leads to various disorders, including liver disorders, metabolic disease, cardiovascular disease, and neurological problems. It also impacts several bodily systems, such as the gastrointestinal tract, kidneys, the gut-liver axis (liver disease, hepatocellular carcinoma, autoimmune liver disease, and metabolic-associated fatty liver disease), the gut-lung axis (pneumonia and chronic obstructive pulmonary disease), the gut-microbiota axis (irritable bowel syndrome, inflammatory bowel disease, and constipation or stool hardness), and the gut-islet axis (hypertension, hyperglycaemia, diabetes, and hypercreatinaemia syndrome). Many factors, including medications (antibiotics, anti-tumour, and immunosuppressants), environmental pollutants (heavy metals, pesticides, microplastics, and atmospheric particulates), high levels of nutrients (protein, fat, salt, and sugar), and others (age, disease, habits, and genes), cause and enable gastrointestinal dysbiosis to develop. Nutritional strategies such as the administration of probiotics, prebiotics, antibiotics, or phytogenic feed additives, and the consumption of a high-quality, balanced diet, as well as early detection of gut health malfunction and an emphasis on increasing bird resilience, can reduce the risk of dysbiosis, modify the gut microbial balance, and make microbial eubiosis possible.