Temperature-controlled microalgal biofilm detachment and harvesting assisted by ultrasonic from 3D porous substrates grafted with thermosensitive gels.

Microalgae have been renowned as the most promising energy organism with significant potential in carbon fixation. In the large-scale cultivation of microalgae, the 3D porous substrate with higher specific surface area is favorable to microalgae adsorption and biofilm formation, whereas difficult for biofilm detachment and microalgae harvesting. To solve this contradiction, N-isopropylacrylamide, a temperature-responsive gels material, was grafted onto the inner surface of the 3D porous substrate to form temperature-controllable interface wettability. The interfacial free energy between microalgae biofilm and the substrates increased from -63.02 mJ/m2 to -31.89 mJ/m2 when temperature was lowered from 32 °C to 17 °C, weakening the adsorption capacity of cells to the surface, and making the biofilm detachment ratio increased to 50.8%. When further cooling the environmental temperature to 4 °C, the detachment capability of microalgae biofilm kept growing. 91.6% of the cells in the biofilm were harvesting from the 3D porous substrate. And the biofilm detached rate was up to 19.84 g/m2/h, realizing the temperature-controlled microalgae biofilm harvesting. But, microalgae growth results in the secretion of extracellular polymeric substances (EPS), which enhanced biofilm adhesion and made cell detachment more difficult. Thus, ultrasonic vibration was used to reinforce biofilm detachment. With the help of ultrasonic vibration, microalgae biofilm detached rate increased by 143.45% to 41.07 g/m2/h. These findings provide a solid foundation for further development of microalgae biofilm detachment and harvesting technology.

Design, Synthesis, and Biological Evaluation of Novel Tetrahydroacridin Hybrids with Sulfur-Inserted Linkers as Potential Multitarget Agents for Alzheimer's Disease.

Alzheimer's disease (AD) is a complex neurodegenerative disease that can lead to the loss of cognitive function. The progression of AD is regulated by multiple signaling pathways and their associated targets. Therefore, multitarget strategies theoretically have greater potential for treating AD. In this work, a series of new hybrids were designed and synthesized by the hybridization of tacrine (4, AChE: IC50 = 0.223 µM) with pyrimidone compound 5 (GSK-3ß: IC50 = 3 µM) using the cysteamine or cystamine group as the connector. The biological evaluation results demonstrated that most of the compounds exhibited moderate to good inhibitory activities against acetylcholinesterase (AChE) and glycogen synthase kinase 3ß (GSK-3ß). The optimal compound 18a possessed potent dual AChE/GSK-3ß inhibition (AChE: IC50 = 0.047 ± 0.002 µM, GSK-3ß: IC50 = 0.930 ± 0.080 µM). Further molecular docking and enzymatic kinetic studies revealed that this compound could occupy both the catalytic anionic site and the peripheral anionic site of AChE. The results also showed a lack of toxicity to SH-SY5Y neuroblastoma cells at concentrations of up to 25 µM. Collectively, this work explored the structure-activity relationships of novel tetrahydroacridin hybrids with sulfur-inserted linkers, providing a reference for the further research and development of new multitarget anti-AD drugs.

Temperature-controlled microalgae biofilm adsorption/desorption in a thermo-responsive light-guided 3D porous photo-bioreactor for CO2 fixation.

Microalgae biofilm-based culture provides an efficient CO2 reduction and wastewater treatment method for its high photosynthetic efficiency and density. As supporting substrates for microalgae biofilm, porous materials have a big available adsorption area, but mutual shading makes it difficult to transmit external light to the internal surface for attached cells' photosynthesis. Thus, light-guided particles (SiO2) were introduced into photosensitive resin to fabricate a light-guided ordered porous photobioreactor (PBR) by 3D printing technology in this study. The space utilization of the PBR was significantly enhanced and the effective microalgae adsorption area was increased by 13.6 times. Further, a thermo-responsive hydrogel was grafted onto the surface of the substrate to form a smart temperature-controllable interface that could enhance microalgae adsorption and desorption in both directions. When the thermo-responsive layer received light, it would generate heat due to the hydrogel's photo-thermal effect. And the surface temperature would then raise to 33 °C, higher than the hydrogel phase transition point of 32 °C, making the surface shrinking and more hydrophobicity for microalgae cells attachment. The microalgae cells' adsorption capacity increased by 103%, resulting in a high microalgae growth rate of 3.572 g m-2 d-1. When turning off the light, the surface temperature would cool down to below 20 °C, the surface would shrink. And the biofilm shows a 564.7% increase in desorption ability, realizing temperature-controlled microalgae harvesting.

ZnO-NPs alleviate aflatoxin B1-induced hepatoxicity in ducklings by promoting hepatic metallothionein expression.

Aflatoxin B1 (AFB1) is a mycotoxin widely present in animal feed and human food, posing a serious threat to animal and human health. This study was aim to illustrate the mechanism of the protective role of MT against AFB1-induced hepatotoxicity, as well as to explore the feasibility of enhancing the tolerance of poultry to AFB1 by upregulating the expression of hepatic MT. After being exposed to AFB1 (50 ng/kg) primary duckling hepatocytes, the cell viability, the antioxidant index (SOD and GPx) and the mRNA levels of MT downstream genes (PTGR, p53, TrxR, AR and Bcl-2) significantly (p < 0.05) decreased, while the intracellular formation of (AFBO)-DNA adduct content, apoptosis, and MDA content significantly (p < 0.05) increased. Interestingly, overexpression of MT in primary duckling hepatocytes markedly (p < 0.05) reversed the detrimental impact of AFB1 and increased the expression of MT downstream genes. HepG2 cells were applied to study the mechanism how MT works to relieve the hepatic toxicity of AFB1. The ZnO-NPs (20 µg/mL) + AFB1 (20 µg/mL) group significantly (p < 0.05) increased the cell viability, the expression of NRF2, NQO1 and SOD, and expression of MT and MTF-1, as well as significantly (p < 0.05) decreased LDH, ROS and apoptotic rate, comparing with the AFB1 group. While joint treatment with AFB1 and ZnO-NPs, the hepatic toxicity exerted by AFB1 alone was reversed, along with the translocation of MTF-1 from the cytoplasm to the nucleus and upregulated its expression. Duckling trails were further carried out. A total number of 96 1-day-old healthy Cherry Valley commercial ducklings were randomly allocated according to a 2 by 2 factorial arrangement of treatments with the main factors including oral administration of AFB1 (0 vs. 40 µg/kg) and dietary supplementation of ZnO-NPs (0 vs. 60 mg/kg) for 7 days. It showed that AFB1 exposure caused body weight loss (p < 0.05), impaired liver structure and failure in hepatic function (activity of ALT, AST and concentration of TP and GLU) (p < 0.05), and decreases in antioxidant capacity(activity of SOD, CAT and concentration of GSH) (p < 0.05), along with the decrease in hepatic concentration of Zn, increase in expression of apoptosis-related genes and protein CAS3 and mRNA Bcl-2 expression (p < 0.05), and suppressed mRNA levels of antioxidant-related genes MT, SOD1, NRF2, and NQO1 (p < 0.05). In accordance with the cell test, dietary supplementation with ZnO-NPs mitigated the toxicity exerted by AFB1. In conclusion, ZnO-NPs has the protective effects against AFB1-induced hepatocyte injury by activating the expression of MTF-1 and the ectopic induction of MT expression, providing detailed information on the detoxification ability of MT on AFB1.

Comprehensive modeling and predicting light transmission in microalgal biofilm.

Biofilm-based microalgae culture combined with wastewater treatment is a promising biotechnology for environmental management. Light availability influences the accumulation of microalgal biomass and nutrient removal. A light attenuation model which comprehensively considered microalgal biofilm structure (density and biofilm thickness), pigments content, and extracellular polymeric substances content was developed to predict the light attenuation in biofilm according to the simplification of the radiative transfer equation. The predicted results were in good overall agreement with the experiment, with an average error of less than 9.02%. These factors (biofilm density, thickness, pigments content, and extracellular polymeric substances content) all contributed to the light intensity attenuation, but biofilm thickness caused the most dramatic attenuation under the same increment of relative change in actual culture. The scattering coefficient of the biofilm (0.433 m2/g) was less than that of the suspension (1.489 m2/g) under white incident light. It suggests that the dense structure of cells allows much light to be concentrated in the forward direction when transmitting. This model could be adopted to predict the light distribution in microalgal biofilm for the further design of efficient photobioreactors and the development of light optimization strategies.

Comparative secretomic and proteomic analysis reveal multiple defensive strategies developed by Vibrio cholerae against the heavy metal (Cd2+, Ni2+, Pb2+, and Zn2+) stresses.

Vibrio cholerae is a common waterborne pathogen that can cause pandemic cholera in humans. The bacterium with heavy metal-tolerant phenotypes is frequently isolated from aquatic products, however, its tolerance mechanisms remain unclear. In this study, we investigated for the first time the response of such V. cholerae isolates (n = 3) toward the heavy metal (Cd2+, Ni2+, Pb2+, and Zn2+) stresses by comparative secretomic and proteomic analyses. The results showed that sublethal concentrations of the Pb2+ (200 µg/mL), Cd2+ (12.5 µg/mL), and Zn2+ (50 µg/mL) stresses for 2 h significantly decreased the bacterial cell membrane fluidity, but increased cell surface hydrophobicity and inner membrane permeability, whereas the Ni2+ (50 µg/mL) stress increased cell membrane fluidity (p < 0.05). The comparative secretomic and proteomic analysis revealed differentially expressed extracellular and intracellular proteins involved in common metabolic pathways in the V. cholerae isolates to reduce cytotoxicity of the heavy metal stresses, such as biosorption, transportation and effluxing, extracellular sequestration, and intracellular antioxidative defense. Meanwhile, different defensive strategies were also found in the V. cholerae isolates to cope with different heavy metal damage. Remarkably, a number of putative virulence and resistance-associated proteins were produced and/or secreted by the V. cholerae isolates under the heavy metal stresses, suggesting an increased health risk in the aquatic products.

Diverse Aquatic Animal Matrices Play a Key Role in Survival and Potential Virulence of Non-O1/O139 Vibrio cholerae Isolates.

Vibrio cholerae can cause pandemic cholera in humans. The waterborne bacterium is frequently isolated from aquatic products worldwide. However, current literature on the impact of aquatic product matrices on the survival and pathogenicity of cholerae is rare. In this study, the growth of eleven non-O1/0O139 V. cholerae isolates recovered from eight species of commonly consumed fish and shellfish was for the first time determined in the eight aquatic animal matrices, most of which highly increased the bacterial biomass when compared with routine trypsin soybean broth (TSB) medium. Secretomes of the V. cholerae isolates (draft genome size: 3,852,021-4,144,013 bp) were determined using two-dimensional gel electrophoresis (2DE-GE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques. Comparative secretomic analyses revealed 74 differential extracellular proteins, including several virulence- and resistance-associated proteins secreted by the V. cholerae isolates when grown in the eight matrices. Meanwhile, a total of 8,119 intracellular proteins were identified, including 83 virulence- and 8 resistance-associated proteins, of which 61 virulence-associated proteins were absent from proteomes of these isolates when grown in the TSB medium. Additionally, comparative genomic and proteomic analyses also revealed several strain-specific proteins with unknown functions in the V. cholerae isolates. Taken, the results in this study demonstrate that distinct secretomes and proteomes induced by the aquatic animal matrices facilitate V. cholerae resistance in the edible aquatic animals and enhance the pathogenicity of the leading waterborne pathogen worldwide.

Analysis of the Influence of Network Continuous Care on the Quality of Life of Patients with Coronary Artery Disease (CAD) after PIC.

Studies have shown that most patients after PCI cannot adhere to the cardiac rehabilitation program. The survey found that due to the lack of secondary prevention of cardiac rehabilitation, the phenomenon of drug reduction and withdrawal after PCI is very common after discharge, leading to recurrence of the patient's disease or worsen and repeated hospitalizations, so continuity of care is very important. In this paper, in addition to proposing a network care continuum with artificial intelligence handler in order to improve the healthcare system and provide new ideas for improving the postoperative recovery of CHD patients, we analyze the impact of PCI on the coronary heart disease patients' PCI postoperative quality of life. In the method part, this article introduces the concepts of continuation care and PCI after surgery, introduces the marker delivery algorithm in the field of artificial intelligence, and introduces the SF-36 scale for patient quality of life analysis. This article designs an experiment combining artificial intelligence processors to carry out network continuity care for patients and divides 100 eligible patients into an experimental group and a control group. In the analysis part, the two groups of patients were analyzed in terms of general data comparison, physical function, biochemical indicators, quality of life, and dependence. It can be seen from the experimental analysis that the anxiety and depression of the two groups of subjects have different degrees of decline. The HAMA value of the experimental group is 9.06 ± 0.77, and the HAMD value is 9.18 ± 1.20, which is significantly lower than that of the control group, P < 0.05. It can be seen that the use of network continuation care can reduce the negative emotions of patients more than general care. Through psychological counseling and postoperative follow-up, it can improve the optimism and positive emotions of the patients, reduce the negative emotions of the patients, and improve it to a certain extent.

Transcriptomics and transmission ultrastructural examination reveals the nephrotoxicity of cadmium in laying hens.

The objective of this study was to reveal the effects of cadmium (Cd) on ultrastructural changes, oxidative stress, and transcriptome expression in the kidneys of laying hens. Seventy-two healthy Hy-Line brown laying hens at 41 weeks old were randomly allocated to four treatment groups with six replicates. The control group received a basal diet without additional Cd incorporation, and the other three treatment groups received diets supplemented with 15, 30, or 60 mg Cd /kg of feed. After 6 weeks of exposure, the results show that administration of 60 mg/kg Cd significantly reduced (P < 0.05) eggshell thickness. With an increase in the Cd concentration in feed, the concentrations of renal Zn and Fe also had changed. Renal histopathology and ultrastructure also showed aggravated damage to glomeruli and renal tubules and the deformation of nuclei and mitochondria in all Cd treatment groups. With an increase in Cd in feed, the activity of glutathione peroxide (GPX) and catalase (CAT) was significantly reduced (P < 0.05), while the activity of total antioxidant capacity (T -AOC) was decreased (P < 0.05) only in the 60 mg/kg Cd group. RNA-seq analysis revealed that 410 genes displayed differential expression (≥ 1.5-fold) in the 60 mg/kg supplementation group, compared to the control group. GO and KEGG pathway analysis results showed that Cd affected many genes involved in mitochondria and ion transport. In conclusion, this study elaborates the mechanisms underlying renal toxicity caused by Cd, which might provide target candidate genes for alleviating Cd poisoning in laying hens.

Effects of Dietary Cottonseed Oil and Cottonseed Meal Supplementation on Liver Lipid Content, Fatty Acid Profile and Hepatic Function in Laying Hens.

Antinutrients, such as cyclopropene fatty acids (CPFAs) and free gossypol (FG), present together in cottonseed have caused numerous adverse effects on liver health and egg quality of laying hens, which are both likely to be related to a disturbance in lipid metabolism. This experiment employed a 3 × 3 factorial arrangement using corn-soybean-meal-based diets supplemented with different levels of cottonseed oil (0%, 2%, or 4% CSO) containing CPFAs and cottonseed meal (0%, 6%, or 12% CSM) containing FG to elucidate the effects of them or their interaction on fatty acid profile, lipid content, and liver health of laying hens. An overall increase in fatty acid saturation and an overall significant decrease (p < 0.05) in monounsaturated fatty acids (MUFAs) were shown in the livers of hens fed diets with either 2% or 4% CSO. Meanwhile, the concentration of liver cholesterol, serum cholesterol, and serum LDL-c of hens fed a diet supplemented with a high level of CSO (4%) were noticeably increased (p < 0.05). Even though the supplementation of 4% CSO in diets aroused beneficial influences on liver function, a high level of CSO inclusion in laying hens' diets is not recommended due to its hypercholesterolemia effect. In conclusion, supplementation of CSO, which contains 0.20% CPFAs, was the primary cause of alteration in fatty acid composition and cholesterol content in hens, while no interaction between CSM and CSO nor CSM effect was found for lipid profile and liver health in laying hen.

Sodium Butyrate Protects the Intestinal Barrier by Modulating Intestinal Host Defense Peptide Expression and Gut Microbiota after a Challenge with Deoxynivalenol in Weaned Piglets.

This study aims to determine whether sodium butyrate (SB) could antagonize deoxynivalenol (DON)-induced intestinal epithelial dysfunction. In a four-week feeding trial, twenty-eight barrows were randomly divided into four treatments: (1) uncontaminated basal diet (control); (2) 4 mg/kg DON-contaminated diet (DON); (3) basal diet supplemented with 0.2% SB (SB); and (4) 4 mg/kg DON + 0.2% SB (DON + SB). A decrease in performance was observed in DON-exposed animals, which was prevented by the dietary SB supplementation. DON exposure also depressed the expression of host defense peptides (HDPs) in the intestine, impaired the intestinal barrier integrity, and disturbed the gut microbiota homeostasis. These alterations induced by DON were attenuated by SB supplementation. The supplementation of 0.2% SB ameliorated the adverse effects of DON on the liver in terms of hepatic lesions as well as serum concentrations of alkaline phosphatase and aspartate aminotransferase. In IPEC-J2 cells, pretreatment with SB alleviated the DON-induced decreased cell viability. Additionally, the NOD2/caspase-12 pathway participated in the alleviation of SB on DON-induced diminished HDP expression. Taken together, these data demonstrated that SB protected piglets from DON-induced intestinal barrier dysfunction potentially through stimulation of intestinal HDP assembly and regulation in gut microbiota.

Heavy Metal Content in Feedstuffs and Feeds in Hubei Province, China.

ABSTRACT: Heavy metal pollution threatens the health and life of animals and humans through the food chain. This study was performed to survey the heavy metal contamination in feedstuffs and feeds in Hubei Province, People's Republic of China, from 2012 to 2016. Samples were analyzed for cadmium (306 samples), mercury (117 samples), chromium (149 samples), and arsenic (4,358 samples) using atomic absorption spectrometry or atomic fluorescence spectrometry. The incidence rates of cadmium, mercury, chromium, and arsenic contamination of feedstuffs and feeds were high, and feeds were most often contaminated with chromium, followed by arsenic, cadmium, and mercury. The concentrations of heavy metals in samples positive for cadmium, mercury, chromium, and arsenic ranged from 0.001 to 1.200, 0.002 to 6.540, 0.060 to 8737.000, and 0.070 to 33.000 mg/kg, respectively. The mineral and additive samples had higher concentrations of heavy metals. The present study findings highlight the importance of monitoring heavy metals in feedstuffs and feeds and implementing feed management and bioremediation strategies to reduce heavy metal exposure.

Effects of dietary cadmium supplementation on production performance, cadmium residue in eggs, and hepatic damage in laying hens.

This study was conducted to investigate the adverse effects of cadmium (Cd) on the production performance, serum biochemistry, liver antioxidant status, histopathology, and egg residue in laying hens. A total of 72 healthy Hy-Line brown laying hens at 40-week-old were randomly assigned to four diets containing 0 (control diet), 15, 30, or 60 mg/kg Cd for 6 weeks. Laying hens exposed to 60 mg/kg Cd had lower egg production rate and worse feed to egg ratio (P < 0.05). Dietary Cd exposure (≥ 15 mg/kg) significantly decreased hepatic glutathione peroxide (GPX) activities, while increasing malondialdehyde (MDA) (P < 0.05). Hepatic histopathology and ultrastructure also showed damage and the symptoms were exacerbated in a dose-dependent manner. The residue of Cd in the yolk was increased with increasing dietary Cd concentration. The mRNA expression levels of mt4L, mt3, sod1, sod2, gpx1, gpx3, and gpx4 in the liver of laying hens exposed to 60 mg Cd/kg feed were significantly decreased (P < 0.05). In conclusion, dietary Cd exposure at ≥ 15 mg/kg induced hepatic damage in laying hens, indicating that the content of Cd in feed must be critically controlled.

Potential Link between Gut Microbiota and Deoxynivalenol-Induced Feed Refusal in Weaned Piglets.

This study investigated the potential link between gut microbiota and deoxynivalenol (DON)-induced feed refusal. A total of 24 barrows were randomly divided into one of three diets containing 0.61 (control diet), 1.28, or 2.89 mg DON/kg feed for 28 days. Dietary exposure to DON at 2.89 mg/kg significantly decreased the relative abundances of unclassified_f_Lachnospiraceae, Phascolarctobacterium and Ruminococcaceae_UCG-014, whereas it increased Prevotella_9 and norank_f_Prevotellaceae in the cecal digesta. Moreover, the decreased relative abundance of unclassified_f_Lachnospiraceae induced by DON exposure was positively correlated with average daily feed intake. Exposure to DON increased the serum concentrations of glucagon-like peptide-1 and peptide YY but reduced the levels of serum growth hormone and insulin-like growth factor 1. In summary, these findings suggest that chronic dietary exposure to DON induces disturbances of intestinal microbiota. Disturbed appetite-regulating hormones and somatotropic-axis-hormone secretion induced by negative microbial changes could be the potential mechanisms for DON-induced anorexia.

Deoxynivalenol Inhibits Porcine Intestinal Trefoil Factors Expression in Weanling Piglets and IPEC-J2 Cells.

Trefoil factors (TFFs) are regulatory peptides playing critical roles in mucosal repair and protection against a variety of insults within the gastrointestinal tract. This work aimed to explore the effects of deoxynivalenol (DON) on intestinal TFFs expression using in vivo and in vitro models. In an animal trial, twenty-four 28-d-old barrows (Duroc × Landrace × Large White; initial body weight = 7.6 ± 0.7 kg) were randomly divided into three treatments for 28 days, including a control diet (0.61 mg DON/kg feed), and two levels of DON-contaminated diets containing 1.28 and 2.89 mg DON/kg feed, respectively. Piglets exposed to DON had lower mRNA expression of TFF1, TFF2, TFF3, as well as Claudin-4 in the intestine (P < 0.05). Dietary DON exposure decreased the protein levels of TFF2 and TFF3 in the jejunum as demonstrated by western blot and immunohistochemistry. In intestinal porcine epithelial cells (IPEC-J2), DON depressed the mRNA expression of TFF2, TFF3, and Claudin-4. Overexpression of sterile alpha motif (SAM) pointed domain E26 transformation-specific (ETS) factor (SPDEF) was found to attenuate DON-induced suppression of TFFs in IPEC-J2 cells. Altogether, our work shows, for the first time, that dietary DON exposure depresses the expression of intestinal TFFs in piglets. Given the fundamental role of TFFs in intestinal mucosal homeostasis, our observations indicate that the DON content in animal feed should be strictly controlled based on the existing regulation for DON.

Deoxynivalenol Impairs Porcine Intestinal Host Defense Peptide Expression in Weaned Piglets and IPEC-J2 Cells.

Host defense peptides (HDPs) are efficient defense components of the innate immune system, playing critical roles in intestinal homeostasis and protection against pathogens. This study aims to investigate the interference effects of DON on the intestinal porcine HDPs expression in piglets and intestinal porcine epithelial cell line (IPEC-J2) cells, and elucidate the underlying mechanisms through which it functions. In an animal experiment, intestinal HDPs were determined in weaned piglets fed control and 1.28 mg/kg or 2.89 mg/kg DON-contaminated diets. Dietary exposure to DON significantly decreased piglet average daily gain, increased intestinal permeability and depressed the expression of porcine ß-defensin1 (pBD1), pBD2, pBD3, epididymis protein 2 splicing variant C (pEP2C), PMAP23, and proline/arginine-rich peptide of 39 amino acids (PR39) in the intestine (p < 0.05). In IPEC-J2 cells, DON decreased cell viability and inhibited the expression of pBD1, pBD3, pEP2C, PG1-5, and PR39 (p < 0.05). NOD2, key regulator that is responsible for HDPs production, was markedly downregulated, whereas caspase-12 was activated in the presence of DON. In conclusion, DON induced caspase-12 activation and inhibited the NOD2-mediated HDPs production, which led to an impaired intestinal barrier integrity of weaned piglets. Our study provides a promising target for future therapeutic strategies to prevent the adverse effects of DON.

A field pilot-scale study of biological treatment of heavy oil-produced water by biological filter with airlift aeration and hydrolytic acidification system.

Heavy oil-produced water (HOPW) is a by-product during heavy oil exploitation and can cause serious environmental pollution if discharged without adequate treatment. Commercial biochemical treatment units are important parts of HOPW treatment processes, but many are not in stable operation because of the toxic and refractory substances, salt, present. Therefore, pilot-scale experiments were conducted to evaluate the performance of hydrolytic acidification-biological filter with airlift aeration (HA-BFAA), a novel HOPW treatment system. Four strains isolated from oily sludge were used for bioaugmentation to enhance the biodegradation of organic pollutants. The isolated bacteria were evaluated using 3-day biochemical oxygen demand, oil, dodecyl benzene sulfonic acid, and chemical oxygen demand (COD) removals as evaluation indices. Bioaugmentation enhanced the COD removal by 43.5 mg/L under a volume load of 0.249 kg COD/m(3) day and hydraulic retention time of 33.6 h. The effluent COD was 70.9 mg/L and the corresponding COD removal was 75.0 %. The optimum volumetric air-to-water ratio was below 10. The removal ratios of the total extractable organic pollutants, alkanes, and poly-aromatic hydrocarbons were 71.1, 94.4, and 94.0 %, respectively. Results demonstrated that HA-BFAA was an excellent HOPW treatment system.

Analysis of bacterial diversity in two oil blocks from two low-permeability reservoirs with high salinities.

The community diversities of two oil reservoirs with low permeability of 1.81 × 10(-3) and 2.29 × 10(-3) µm(2) in Changqing, China, were investigated using a high throughput sequencing technique to analyze the influence of biostimulation with a nutrient activator on the bacterial communities. These two blocks differed significantly in salinity (average 17,500 vs 40,900 mg/L). A core simulation test was used to evaluate the effectiveness of indigenous microbial-enhanced oil recovery (MEOR). The results indicated that in the two high salinity oil reservoirs, one reservoir having relatively lower salinity level and a narrow salinity range had higher bacterial and phylogenetic diversity. The addition of the nutrient activator increased the diversity of the bacterial community structure and the diversity differences between the two blocks. The results of the core simulation test showed that the bacterial community in the reservoir with a salinity level of 17,500 mg/L did not show significant higher MEOR efficiency compared with the reservoir with 40,900 mg/L i.e. MEOR efficiency of 8.12% vs 6.56% (test p = 0.291 > 0.05). Therefore, salinity levels affected the bacterial diversities in the two low permeability oil blocks remarkably. But the influence of salinity for the MEOR recovery was slightly.