Oil Concentration Research Articles

Exploring the thermal-induced optical nonlinearity of crude oil via spatial self-phase modulation technique

This study aims to investigate the nonlinear optical (NLO) characteristics of diluted crude oil samples from the Ramshir, Rag-e-Sefid, and Ahwaz-20 reservoir fields in the southwest region of Iran. Utilizing spatial self-phase modulation (SSPM) techniques, we measured the nonlinear refractive index () by observing the intensity-dependent number of diffraction rings with continuous-wave laser beams at and wavelengths. This study focused on examining the ratios of different sample concentrations to identify the role of thermal effects in the observed NLO responses. Our findings indicate a direct correlation between the concentration of crude oil in the samples and their NLO properties, with thermal effects significantly influencing the changes in NLO responses. In the thermal region, the nonlinear refractive index was approximately determined to be . Additionally, the study explores the collapse of diffraction rings to further understand how the relative nonlinear refractive index varies with the sample concentration and incident intensity at both wavelengths. The results suggest that crude oil possesses promising NLO properties, making it potentially suitable for the development of new photonic devices and applications, especially in areas where thermal nonlinearities are crucial, such as sensing and all-optical technologies.

Integrated sand and activated carbon-based filtration for decanted oily wastewater treatment during offshore oil spill response.

Decanted oily wastewater is the generated stream associated with vessel-based skimming operations during offshore oil spill response. It contains a large amount of persistent, bio-accumulative, carcinogenic, and mutagenic oil contaminants, so it is critical to find effective ways to treat it. This study targets the decanted oily wastewater treatment by developing an integrated sand and activated carbon-based filtration approach. Three activated carbons (AC-1, AC-2, AC-3) were evaluated for oil removal from the oil-water mixture. AC-1 demonstrated superior performance with the highest BET surface area (704m2/g) and pore volume (0.231cm³/g). Batch adsorption experiments with AC-1 examined the effects of activated carbon textural characteristics, adsorbent dosage, and contact time on the total oil concentration and removal efficiency of polycyclic aromatic hydrocarbons (PAHs). Column experiments with AC-1 further explored various parameters, including the flow rate, column bed height, oil type, and adsorbent media on the adsorption performance. The findings demonstrate that 34ml/min flow rate, 4cm column height, and a combination of sand and activated carbon as adsorbent media achieved the highest total crude oil (Tera-Nova) and PAH removal efficiency (both 99.9%). By integrating the sand with activated carbon in the filtration system, both dissolved and emulsified petroleum hydrocarbons can be effectively removed. This research provides valuable insights into optimizing activated carbon-based systems in oil-water separation, with practical applications in marine oil spill response and wastewater treatment.

Exposure to mouse dams to bonito broth during gestation or lactation reduces fat intake in offspring.

Overconsumption of fat contributes to obesity and low adherence to dietary therapy in patients with obesity. The frequency of consuming soup dishes containing "dashi" (Japanese broth), a characteristic element of the Japanese diet, is negatively associated with obesity indicators. The use of dashi is considered one of the reasons why the low-fat Japanese diet is popular; however, whether and how dashi controls the selection and intake of fat is unknown. In this study, we tested the hypothesis that bonito broth, a typical Japanese dashi, affects fat consumption in a mouse model. First, we examined the long-term or short-term intake of corn oil emulsion in adult mice fed bonito broth. No significant effect was observed. Next, mouse dams were fed bonito broth during gestation or lactation and licking of 0.5, 1, 2.5, 5, and 10% corn oil in their adult pups was evaluated in acute tests. Compared to the control group, there were significant decreases in licks for some corn oil concentrations in the gestation and lactation groups. Finally, corn oil licking was tested in pups fed bonito broth after weaning. No significant effect was detected. This study suggests that dams' intake of bonito broth during gestation or lactation reduces the intake of fat by their pups in adulthood.

A Comparative Study on the Structural, Physicochemical, Release, and Antioxidant Properties of Sodium Casein and Gelatin Films Containing Sea Buckthorn Oil

The aim of this study was to compare the effect of increasing concentrations (0, 1, 2, 4%) of sea buckthorn oil (SBO) on the structural, physicochemical, release, and antioxidant properties of glycerol-plasticized sodium casein (NaCAS) and gelatin (GEL) films. Ultrasonic treatment ensured effective homogenization of SBO in both types of emulsions, resulting in yellow-tinted semi-opaque films with relatively low micro-roughness. Generally, GEL films demonstrated lower UV barrier properties and solubility but exhibited higher compactness, crystallinity, transparency, surface hydrophobicity, oxygen barrier performance, strength, and antiradical activity compared to their NaCAS-based counterparts. In a concentration-dependent manner, SBO decreased the solubility and water absorption of the gelatin-based film and enhanced its oxygen permeability. Conversely, SBO improved the water vapor barrier properties of both films in a concentration-independent manner. At the highest SBO concentration, the tensile strength of NaCAS- and GEL-based films decreased by 27% and 20%, respectively, while their antiradical activity increased by 9.3× and 4.3× (based on the time required for the half-neutralization of 2,2-diphenyl-1-picrylhydrazyl radicals). Migration studies showed that at the lowest concentration, SBO was released (into 95% ethanol) approximately 2× faster from the GEL-based film than from the NaCAS film, whereas at higher concentrations, the trend reversed.

Integrated approach for removal of oil from contaminated seawater

ABSTRACT This study explores the possibility of oil removal from contaminated seawater using an integrated technology comprising of adsorption using human hair and phycoremediation using the indigenous algal strain Tetradesmus sp. NITD18. The sequential method demonstrated higher oil removal (81.5 ± 0.07%) compared to the simultaneous approach (77 ± 0.7%) after 12 days. Three experimental sets (A: 0.5 g, B: 0.6 g, C: 0.8 g) were designed based on varying amounts of human hair. Parametric studies revealed that optimal conditions were achieved with 0.8 g human hair and 150.9 g/L initial oil concentration during adsorption, yielding 62.5 ± 0.7% removal. During phycoremediation, 10% inoculum concentration showed maximum oil removal of 87 ± 0.14% and highest biomass production (0.127 ± 0.005 g/L). Set# C demonstrated a significant reduction in TDS (from 3925 ± 132 mg/L to 3338 ± 761 mg/L), salinity (from 3.9 ± 0.2 psu to 3.4 ± 0.3 psu), and conductivity (from 9079 ± 162 µS/cm to 4090 ± 141 µS/cm). Maximum concentrations of chlorophyll (48.2 ± 4.43 mg/L), protein (2.55 ± 0.002 mg/L), and carbohydrate (2.55 ± 0.002 mg/L) were obtained from spent algal biomass as obtained in a sequential approach. Hence, it can be stated that the study demonstrates that the sequential approach effectively removal oil from contaminated seawater under optimized conditions.

Assessment of oil vertical diffusion in waters following an oil spill incident in an urban inland waterway.

Accidental oil spills can have a serious impact on water bodies. While most current studies have focused on waves, few have examined water flows, which represent the most common hydrodynamic environment in urban inland waterways. In this study, 12 hydrodynamic conditions were constructed, and the oil vertical diffusion characteristics under hydrodynamic conditions were investigated by measuring oil concentration and oil droplet size distribution at different depths. The main findings include: (1) Oil concentration decays exponentially along the vertical direction, the related parameters follow power and quadratic functions in relation to mean flow velocity, respectively; (2) Oil droplet size distribution was influenced by hydrodynamic characteristics, mean flow velocity was significantly positively correlated with its distribution range; (3) Oil droplet size distribution patterns at different depths were similar, in line with the characteristics of Rosin-Rammler distribution. Based on experimental data, a set of models was constructed to describe and predict the vertical distribution of oil concentration and oil droplet size distribution under hydrodynamic conditions. This study not only reveals the characteristics of oil vertical diffusion under hydrodynamic conditions, but also provides a quantitative framework for understanding the relevant features, which is helpful for the response to the oil spill accident in urban inland waterways.

Wound Healing Ointment Formulation from Essential Oil of Lemongrass (Cymbopogon citratus)

Untreated wound may lead to the infection. In some countries, plants are used to cure wound traditionally. Lemongrass (Cymbopogon citratus) has various bioactive compounds, including citronellol, limonene and geraniol that perform some pharmacological activities. In this study, the essential oil of lemongrass was designed into ointment formulation since lemongrass has been reported to have a wound healing effect in mice. The wound healing ointment made from different concentration of the essential oil of Cymbopogon citratus (F1: EOCC 5%, F2: EOCC 10% and F3: EOCC 15%) using a water-removable base and the characteristic as well as the stability (texture, color, smell, homogeneity, and pH) after been stored for 14 days was also evaluated. The result showed that all formulation (F1, F2, and F3) of wound healing formulation revealed good texture, consistency, odor, color, homogeneity and compatible to the skin until 14 days of storage. However, F3 (EOCC 15%) has a strong lemongrass smell compare to the other formulations.

Revitalization of Old Rose (Rosa damascena Mill.) Garden for Agumenting Growth, Flower Yield and Essential Oil Quality by Pruning and Fertilizer Application

The flower quality and essential oil concentration plays a critical role in marketing in local and international market. To unfold yield potential of the plants in old garden, cultural practices and nutrition remain the only feasible option as a part of management to the farmer to provide congenial environment to the plant. The impact of pruning and fertilizer application on growth, flower yield, volatile oil composition, physiological and biochemical processes are still poorly investigated on damask rose. Hence, the field experiment was led-out with nine treatment conditions encompassing three pruning systems and three fertilizer dosages to standardize the best practice to rejuvenate the old rose garden. The results showed that the pruning at 60 cm from ground level and application of 200:100:100 N, P2O5 and K2O kg ha-1exhibited maximum increase in growth parameters and flowering parameters like bud length (13.17 cm), diameter (5.52 cm), number of flowers per plant (273.41), flower yield (66.54 q ha-1) and vase life (9.37 days) followed by pruning at 45 cm from ground level and application of 150:75:75 N, P2O5 and K2O kg ha-1. Essential oil characters like volatile oil percentage (0.051 %) and volatile oil productivity (0.973 l plant-1) were highest in treatments of pruning at 60 cm from ground level and application of 200:100:100 N, P2O5 and K2O kg ha-1. From the experiment it is suggested that the old rose gardens can be rejuvenated by pruning and fertilizer application for better growth, flower production and increase in essential oil.

Diffusion Characteristics of Dissolved Gases in Oil Under Different Oil Flow Circulations

The prediction of dissolved gas concentrations in oil can provide crucial data for the assessment of power transformer conditions and early fault diagnosis. Current simulations mainly focus on the generation and accumulation of characteristic gases, lacking a global perspective on gas diffusion and dissolution. This study simulates the characteristic gases produced by typical faults at different flow rates. Using ANSYS 2022 R1 simulation software, a gas–liquid two-phase model is established to simulate the flow and diffusion of characteristic gases under fault conditions. Additionally, a fault-simulation gas production test platform was built based on a ±400 kV actual converter transformer. The experimental data show good consistency with the simulation trends. The results indicate that the diffusion of dissolved gases in oil is significantly affected by the oil flow velocity. At higher flow rates, the characteristic gases primarily move within the oil tank along with the oil circulation, leading to a faster rate of gas dissolution in oil and a shorter time to reach equilibrium within the tank. At lower flow rates, the diffusion of characteristic gases depends not only on oil flow circulation but also on self-diffusion driven by concentration gradients, resulting in a nonlinear change in gas concentration across various monitoring points.

Numerical simulations on the separation performance of two-stage mini hydrocyclones connected in series

ABSTRACT Conventional hydrocyclones (CHCs) exhibit limited effectiveness in separating fine oil droplets from produced fluids, constraining overall oil-water separation efficiency. Mini hydrocyclones (MHCs) with smaller main diameter can further enhance the separation efficiency of fine oil droplets. This study constructs a two-stage series separation system using two individual MHCs. Simulations were conducted to investigate the effects of split ratio, water content, and oil droplet size on the separation performance. The adaptability of the series system to these parameters was thereby obtained. Results indicate the optimal separation efficiency is achieved when the total split ratio of the series system is 48%. The two-stage series system has better adaptability to the water content, and the separation efficiency keeps more than 97% when the water content is 86–98%, while the separation efficiency is lower than 92% when the water content is 86% in a single-stage MHC. When the inlet oil concentration exceeds 10%, for oil droplet sizes less than 0.15 mm, the two-stage series system outperforms single-stage MHCs operating independently.

Impact of soy/pea protein isolate-oil interactions on the physicochemical and structural properties of high-moisture texturized proteins under different oil concentrations.

This study investigated the effects of oil addition on the physical and chemical properties of high-moisture texturized proteins (HMTPs), focusing on soy protein isolate (SPI) and pea protein isolate (PPI). Rheological analysis revealed contrasting behaviors: SPI exhibited decreased rheological parameters at low oil concentrations (1, 3 %), followed by a significant increase at higher concentrations (5, 10 %), whereas PPI showed a consistent decline across all oil concentrations. The superior emulsifying and gelling abilities of SPI resulted in stronger protein-protein interactions and greater hardness at higher oil concentrations. In contrast, PPI exhibited minimal protein-oil interactions, reducing hardness and weakening textural properties. Further analysis showed that SPI-based and PPI-based HMTP exhibited structural changes upon oil addition, with contrasting directional shifts due to differing degrees of protein-oil interactions. These results emphasize the critical role of protein selection in optimizing oil-containing HMTP formulations, with SPI demonstrating clear advantages in achieving desirable texture due to its superior functional properties. This study provides valuable insights for developing sustainable plant-based meat analogs, particularly those requiring oil incorporation to replicate the textural and structural characteristics of traditional meat products.

Essential oils extracted from two aromatic plants belonging to the Asteraceae family grown in Northern Algeria as green corrosion inhibitors for carbon steel

This paper investigates the corrosion inhibition properties of natural products, specifically essential oils extracted from the aerial parts of Artemisia judaica L. and Artemisia absinthium L., plants native to the City of Mostaganem, Northern Algeria. The essential oils were obtained through hydrodistillation and evaluated as corrosion inhibitors for steel in a 1 M HCl solution. Corrosion inhibition efficiency was assessed using weight loss measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy. The results demonstrated that the inhibition efficiency increased with higher concentrations of essential oils, achieving maximum efficiencies of (94.84 ± 1.0055)% and (88.42 ± 1.8968)% at a concentration of 2.5 g L−1 for A. absinthium L. and Artemisia judaica L., respectively. Additionally, the influence of temperature on inhibition efficiency was examined, revealing a decline in performance with increasing medium temperature.

Classical and machine learning tools for identifying yellow-seeded Brassica napus by fusion of hyperspectral features.

Due to its favorable traits-such as lower lignin content, higher oil concentration, and increased protein levels-the genetic improvement of yellow-seeded rapeseed has attracted more attention than other rapeseed color variations. Traditionally, yellow-seeded rapeseed has been identified visually, but the complex variability in the seed coat color of Brassica napus has made manual identification challenging and often inaccurate. Another method, using the RGB color system, is frequently employed but is sensitive to photographic conditions, including lighting and camera settings. We present four data-driven models to identify yellow-seeded B. napus using hyperspectral features combined with simple yet intelligent techniques. One model employs partial least squares regression (PLSR) to predict the R, G, and B color channels, effectively distinguishing yellow-seeded varieties from others according to globally accepted yellow-seed classification protocols. Another model uses logistic regression (Logit-R) to produce a probability-based assessment of yellow-seeded status. Additionally, we implement two intelligent models, random forest and support vector classifier to evaluate features selected through lasso-penalized logistic regression. Our findings indicate significant recognition accuracies of 96.55% and 98% for the PLSR and Logit-R models, respectively, aligning closely with the accuracy of previous methods. This approach represents a meaningful advancement in identifying yellow-seeded rapeseed, with high recognition accuracy demonstrating the practical applicability of these models.

Sapote gum as a new biopolymer suitable emulsion stabilizer: Grapeseed oil ultrasonic emulsification

Sapote gum (SG) is a new biopolymer with promissory functional properties. This study aimed to determine if SG is a suitable emulsifier for obtaining stable grape seed oil (GSO) emulsions. In the first stage, coarse emulsion concentrations of SG and grapeseed oil - GSO were evaluated, applying the Central Composite Rotational Design (0.59% to 3.41% of SG and 12.93% to 27.07% GSO). For the second stage, using a Centered Face Design – CFD, the resulting emulsion was sonicated at 90, 270, and 450 Watts at 5, 10, and 15 min. Finally, a validation was made. Emulsions were evaluated through microstructure, droplet size, kinetic stability, heat stress, and rheology. Micrographs of the first-stage emulsions showed droplets up to 3.8 μm diameter and a creaming index between 0.00% and 28.39% after 24 h. Optimization indicates that the higher the concentration of gum (3.5%) and GSO (25%), the more kinetically stable emulsions are produced. Ultrasonic emulsions showed no significant difference in droplet size and kinetic stability before 14 days of rest. Ultrasonic validation was made at 450 W for 6 min, resulting in emulsions stable for 20 days and with rheological characteristics interesting for food or cosmetic industries.

Study of the presence of pro-oxidative properties in phenolic oxidation inhibitors in relation to modern transformer oils

ACTUALITY. In the community of Russian specialists servicing oil-filled transformers, there is an established opinion that when the concentration of the phenolic oxidation inhibitor Ionol (DBPC) in the oil drops below 0.1% (wt.), the transformer oil begins to oxidize faster than in the absence of Ionol. This is the so-called “pro-oxidizing effect” described in 1968. Modern hydrocracking transformer oils differ significantly from the former oils in terms of hydrocarbon composition, but the opinion about the pro-oxidizing properties of Ionol remains, despite the lack of such information in foreign studies. OBJECTIVE. To reveal the presence or absence of pro-oxidative action of phenolic antioxidants, Ionol and 2,6-DTBP, when their concentration in transformer oil is reduced. METHODS. Two series of oil samples were prepared for the study: with Ionol and 2,6-DTBP additive. The concentration of additives: 0; 0.05; 0.1 and 0.2 % (wt.). VG grade oil produced by hydrocracking technology was used as a base mineral oil. All oils were subjected to accelerated thermal degradation at elevated temperature. Destructive changes in the hydrocarbon base of oils were analyzed by IR absorption spectra. Changes in the relative content of degradation products dissolved in the oil were analyzed using UV-visible absorption spectra. RESULTS. On the basis of the analysis of optical spectra of both series of oils, it was obtained that as the initial concentration of any of the phenolic oxidation inhibitors in the oil decreases, the intensity of thermodestructive changes in the hydrocarbon composition of the oils consistently increases. It is shown that in transformer oils produced by hydrocracking technology both additives in the concentration range of 0.05÷0.1 % do not show pro-oxidizing properties. It is concluded that the widespread idea about pro-oxidizing effect of Ionol at its concentration in transformer oil less than 0.1 % should be considered as not corresponding to reality.

Impact of neem oil in controlling powdery mildew (Erysiphe polygoni DC) on green gram (Vigna radiata L.)

Powdery mildew in green gram is attributed to the fungus Erysiphe polygoni DC. This disease poses a significant challenge to crop production, affecting all above-ground parts of the plant. An effective and environmentally friendly approach to managing powdery mildew is the use of neem oil. Various concentrations of neem oil were tested as foliar sprays, including 0.5, 1.0, 1.5, 2.0, and 2.5% alongside a treatment of carbendazim @ 0.1% and an untreated control. Results showed that all treatments notably diminished the severity of the disease and enhanced crop yield. Among the tested concentrations, neem oil @ 2.0% proved to be the most effective, significantly outperforming the other treatments in reducing the intensity of powdery mildew of green gram while also promoting plant growth, yield, and cost effectiveness compared to both the carbendazim @ 1% treatment and the untreated control.

Antibacterial activity of Nigella sativa against multi-drug resistant bacteria

Background: Multidrug Resistant (MDR) bacteria are considered as the one of the most dangerous pathogens causing a high mortality rate globally. Medicines from the natural source might be the best therapeutic option in current emerging trends of resistance. Methods: We determined the antibacterial activity of Nigella sativa seeds extracts against the clinical isolates of MDR Staphylococcus aureus and Escherichia coli. The collection of different isolates was done from the different hospitals’ settings in Faisalabad. Identifications of these isolates were done phenotypically and through the conventional PCR via genus and species-specific primers. The isolates were then tested for antimicrobial susceptibility using agar well diffusion technique. The activity of N. sativa seed oil was also evaluated in DMSO at concentrations (25%, 50% and 75%). Results: Against S. aureus, 50% oil concentration in DMSO exhibited highest inhibitory zone of 15 mm followed by 90% ethanol extract showed clear zone of 13 mm and 12 mm zone of inhibition showed by the methanol-based extract. Against E. coli 50% oil concentration in Dimethyl sulfoxide (DMSO) and 90% ethanol extract both showed clear zone of 12 mm and 11 mm zone of inhibition showed by the methanol-based extract. However, Minimum inhibitory concentration (MIC) of 50% oil concentration is 0.4 μl followed by 90% ethanol extract showed 0.4 mg and 0.8 mg showed by the methanol-based extract 90% on S. aureus. The oil concentration MIC value of 50% is 0.4 μl then followed by the ethanol extract at 90% and revealed 0.4mg and methanol was followed by 90% extract showed 0.4 mg to the E. coli. Conclusion: We concluded that N. sativa can be used as a pharmaceutical and new therapy for action against MDR bacteria.

Color, Structure, and Thermal Stability of Alginate Films with Raspberry and/or Black Currant Seed Oils.

In this study, biodegradable and active films based on sodium alginate incorporated with different concentrations of oils (25% and 50%) from fruit seeds were developed for potential applications in food packaging. The ultraviolet and visible (UV-VIS) spectra of raspberry seed oil (RSO) and black currant seed oil (BCSO) indicated differences in bioactive compounds, such as tocopherols, phenolic compounds, carotenoids, chlorophyll, and oxidative status (amounts of dienes, trienes, and tetraenes) of active components added to alginate films. The study encompassed the color, structure, and thermal stability analysis of sodium alginate films incorporated with RSO and BCSO and their mixtures. The color of alginate films before and after the addition of oils from both fruit seeds was evaluated by measuring color coordinates in the CIELab color space: L* (lightness), a* (red-green), and b* (yellow-blue). The lightness values ranged between 94.21 and 95.08, and the redness values varied from -2.20 to -2.65, slightly decreasing for the films enriched with oils. In contrast, yellowness values ranged between 2.93 and 5.80 for the obtained active materials, significantly increasing compared to the control alginate film (L* = 95.48, a* = -1.92, and b* = -0.14). Changes in the structure and morphology of the alginate films after incorporating bioactive-rich oils were observed using scanning electron microscopy (SEM). Films with RSO and oil mixtures had more developed surfaces than films with BCSO. Moreover, the cross-sections of the films with RSO showed holes evenly distributed inside the films, indicating traces of volatile compounds. Thermal decomposition of the alginate films loaded with oils showed five separate stages (to 125 °C, 125-300 °C, 310-410 °C, 410-510 °C, and 750-1000 °C, respectively) related to the oil and surfactant decomposition. The shape of the thermogravimetric curves did not depend on the oil type. The added oils reduced the efficiency of alginate decomposition in the first stage. The obtained results showed that new functional and thermally stable food packaging films based on sodium alginate with a visual appearance acceptable to consumers could be produced by utilizing oils from fruit seed residues.

Analysis of Eco-Enzyme Potential to Reduce BOD, COD, Oil, and Fat Concentrations in Raw Water for Clean Water in Karawang Regency: A Laboratory Experiment

Organic pollutants are produced by domestic household waste, so eco-enzymes are potentially used as bioremediation agents for community-based water quality and pollution control, as has been conducted in the Citarum Harum Program. However, scientific information regarding eco-enzymes characteristics and their ability to degrade BOD, COD, and oil and grease is limited, especially in surface water used for raw water for treated water. This research examines eco-enzymes potential as biocatalysts to reduce BOD, COD, and oil and grease in raw water for treated water in Karawang primary irrigation canals. Water samples were collected from Karawang primary irrigation canals according to the Indonesian National Standard No. 8995:2021. Meanwhile, the eco-enzyme is made from fruit peel and molasses for 624 days. The experiments were carried out with five variations of raw water and eco-enzymes mixtures (v/v) of 3,000.00:0.00 mL; 2,900.00:100.00 mL; 2,850.00:150.00 mL; 2,800.00:200.00 mL; and 2,750.00:250.00 mL with a batch flow system for ten days. The results showed that eco-enzymes contained protease, amylase, and lipase as much as 1,231.00 U/mL; 4.00 U/mL; and 9.69 U/mL, respectively, with a pH of 3.80. The concentrations of BOD, COD, and oil and grease in the current study tended to increase from 222.00 mg/L; 1,047.00 mg/L, and 2.20 mg/L to 505.00-593.00 mg/L; 1245.50-1941.50 mg/L; and 6.60-9.00 mg/L, respectively, which might be due to the addition of organic compounds through mixing eco-enzymes that makes the biodegradation process takes longer. These results indicate that eco-enzymes are less appropriate for surface water treatment with continuous flow systems and more suitable for biological treatment of communal wastewater in batch flow systems.

Effect of konjac glucomannanaerogel-immobilized Chlorella vulgaris LH-1 on oil-contaminated seawater remediation and endogenous bacterial community diversity.

Ocean oil spills can severely impact ecosystems and disrupt marine biodiversity and habitats. Microbial remediation is an effective method for removing thin oil slick contamination. In this study, the adsorption and degradation of low-concentration oil spills by Chlorella vulgaris LH-1 immobilized in konjac glucomannan (KGM) aerogel were investigated. The effect of the KGM aerogel-immobilized C. vulgaris on the bacterial community structure in seawater environments was analyzed through bacterial diversity sequencing. In seawater containing 0.01 and 1.00 g/L of crude oil, after 14 days of remediation with the KGM aerogel-immobilized C. vulgaris, crude oil removal rates of 98.73% and 95.13% were achieved, respectively. The FDA hydrolytic enzyme activity curve indicated that the microbial growth activity in the immobilized C. vulgaris group was significantly higher than that in other groups. After remediation, the top three dominant bacterial genera in the seawater were found to be Vitellibacter, Roseitalea, and Methylophaga. Vitellibacter, a genus known for its ability to degrade polycyclic aromatic hydrocarbons (PAHs) in marine environments, showed increased abundance in seawater treated with the KGM aerogel-immobilized C. vulgaris, suggesting enhanced PAH degradation capability in the presence of the immobilized C. vulgaris. Functional prediction using PICRUSt indicated that the oil metabolism capability of bacteria was promoted by the KGM aerogel-immobilized C. vulgaris. PRACTITIONER POINTS: High degradation efficiency across various oil concentrations is exhibited by KGM-immobilized microalgae. KGM aerogels effectively confine C.vulgaris, reducing loss in marine systems. The impact of KGM aerogel-immobilized C. vulgaris on bacterial community structure in marine environments was analyzed. Immobilized C. vulgaris enhanced the growth of polycyclic aromatic hydrocarbon-degrading bacteria, such as Vitellibacter, in seawater.