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The formation process of the algae-bacteria symbiotic system (ABSS) was analyzed, and the formation adsorption conditions were optimized. The role of extracellular polymeric substances (EPS), specific surface area and zeta potential in adsorption mechanisms were assessed and proposed. The results showed the dry weight of the ABSS and adsorption efficiency of microalgae reached the highest under the conditions of 25 °C, pH 6.0, 160 rpm and CaCl 2  2.0 mg/mL. The process of the ABSS formation could be mainly divided into the fast stage and slow stage. The roles of EPS, specific surface area and zeta potential accounted for 84.22%, 5.17% and 10.61% of the adsorption capacity, respectively. EPS dominated the formation of the ABSS. The results indicated that mycelial pellets were biosorption materials and had the characteristics of chemical materials., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Tourmaline is a ring borosilicate with unique pyro-electricity and piezoelectricity values. Non-gem tourmaline is usually used as an environmental material. The short-term effects of ultrafine tourmaline particles on nitrogen removal performs microbial population dynamics. Key functional species in a sequencing batch reactor were investigated at 9 ± 1 °C. The investigation results showed that 1 g·L −1 ultrafine tourmaline particles could resist the effect of temperature shock on the metabolism of NH₄⁺-N and were beneficial to the restoration of the metabolism capacity of NH₄⁺-N. 1 g·L −1 ultrafine tourmaline particles, which increased the oxidation rate of NH₄⁺-N in the aerobic phase, the formation rate of NO₃ − -N in the aerobic phase, and the denitrification rate in the hypoxia phase at low temperatures. However, the community richness or diversities were not changed after short-term exposure to 1 g·L −1 ultrafine tourmaline particles at low temperatures and 1 g·L −1 ultrafine tourmaline particles could not change the relative abundances of functional microbes except nitrite oxidizing bacteria.

The low-strength domestic wastewater (LSDW) treatment with low chemical oxygen demand (COD) has drawn extensive attention for the poor total nitrogen (TN) removal performance. In the present study, an enhanced multistage anoxic/oxic (A/O) biofilm reactor was designed to improve the TN removal performance of the LSDW treatment. Efficient nitrifying and denitrifying biofilm carriers were cultivated and then filled into the enhanced biofilm reactor as the sole microbial source. Step-feed strategy and internal recycle were adopted to optimize the substrate distribution and the organics utilization. Key operational parameters were optimized to obtain the best nitrogen and organics removal efficiencies. A hydraulic retention time of 8 h, an influent distribution ratio of 2:1 and an internal recycle ratio of 200% were tested as the optimum parameters. The ammonium, TN and COD removal efficiencies under the optimal operational parameters separately achieved 99.75 ± 0.21, 59.51 ± 1.95 and 85.06 ± 0.79% with an organic loading rate at around 0.36 kg COD/m 3  d. The high-throughput sequencing technology confirmed that nitrifying and denitrifying biofilm could maintain functional bacteria in the system during long-period operation. Proteobacteria and Bacteroidetes were the dominant phyla in all the nitrifying and denitrifying biofilm samples. Nitrosomonadaceae_uncultured and Nitrospira sp. stably existed in nitrifying biofilm as the main nitrifiers, while several heterotrophic genera, such as Thauera sp. and Flavobacterium sp., acted as potential genera responsible for TN removal in denitrifying biofilm. These findings suggested that the enhanced biofilm reactor could be a promising route for the treatment of LSDW with a low COD level.

Bacteria can coordinate and synchronize activities through a cell density-dependent regulatory mechanism called quorum sensing (QS). Bacteria can measure their population by the synthesis, secretion, and perception of QS signal molecules to regulate specific gene expression when the population reaches a critical threshold. QS participates in various microbial processes such as marine organism bioluminescence, bacterial biofilm formation, and virulence factor expression. The use of QS systems mediated by N-acyl-homoserine lactones and autoinducer-2 has been recently recognized as a promising regulatory approach in environmental science and technology that can intrinsically promote the profound comprehension of wastewater treatment from a microbiology perspective. This article reviewed the study of QS in several environmental systems in wastewater treatment, including systems of aerobic granular sludge, biological nitrogen removal, and bioaugmentation, while several future prospects and suggestions are proposed on the basis of current studies.

Bioaugmentation is substantially determined by pre-attached communities in biological stuffing systems. However, the inevitable changes of microbial community shift occurred between pre-attached microorganisms on stuffing material and other existing communities in wastewater. Targeting at nitrogen removal in aerobic denitrification reactors, biological augmentation was built by polyurethane supporting material and aerobic denitrification bacteria of Pseudomonas stutzeri strains were primarily colonized. The total nitrogen removal reached a high efficiency of 77 ± 6%, resulting from a relative high nitrate removal (90%) and a low nitrite production of 24 mg l -1 . The nitrate removal was kept 10% higher using preattached strains than that using wastewater communities. During the bioaugmentation process, abundant bacteria related to nitrogen removal were evolutively enriched to compete with preattached Pseudomonas stutzeri. The most abundant bacteria growing up in the biofilm belonged to various Classes of Proteobacteria Phylum. A noticeable nitrite production with a relative low TN removal efficiency occurred when Brucella sp. and Brevundimonas sp. were simultaneously enriched in place of Pseudomonas, because Brevundimonas also accumulated nitrite during denitrification under an aerobic condition. The results indicated that pre-attached denitrifiers in comprehensive communities on stuffing material can be established for the efficient nitrogen and COD removal in aerobic denitrification reactors.

Sulfate-reducing bacteria (SRB) are widely existed in oil production system, and its H2S product inhibits rhamnolipid producing bacteria. In-situ production of rhamnolipid is promising for microbial enhanced oil recovery. Inhibition of SRB, removal of H2S and production of rhamnolipid by recombinant Pseudomonas stutzeri Rhl were investigated. Strain Rhl can simultaneously remove S(2-) (>92%) and produce rhamnolipid (>136mg/l) under S(2-) stress below 33.3mg/l. Rhl reduced the SRB numbers from 10(9) to 10(5)cells/ml, and the production of H2S was delayed and decreased to below 2mg/l. Rhl also produced rhamnolipid and removed S(2-) under laboratory simulated oil reservoir conditions. High-throughput sequencing data demonstrated that addition of strain Rhl significantly changed the original microbial communities of oilfield production water and decreased the species and abundance of SRB. Bioaugmentation of strain Rhl in oilfield is promising for simultaneous control of SRB, removal of S(2-) and enhance oil recovery., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

This work focused on wastewater reclamation of secondary treated ethylene chemical plant effluent, which contained high conductivity and high organic concentration. To reduce the cost and improve operation stability, a biological aerated filter-ultrafiltration-reverse osmosis (BAF-UF-RO) process was proposed. The feasibility and effectiveness of BAF loaded with a novel non-sintered fly-ash ceramsite (NSFC) as a pretreatment method of a dual membrane system were investigated in detail. The results showed that the CODCr, turbidity, NH3-N and the silt density index (SDI) in the effluent from the BAF were reduced to 24.2 mg/L, 12.17 NTU, 0.42 mg/L and 7.52, respectively, and most of the organic compounds were biodegraded. The BAF-UF-RO process was stable with a recovery rate of 75%, and the desalination rate was up to about 97.5%. Compared with the UF-RO process, the operating pressure and backwash frequency decreased from 1.12-1.26 Mpa and 3 times/d to 0.94-0.98 Mpa and 2 times/d, respectively. After continuous operation for four months, there appeared to be no need for chemical cleaning of the RO membrane. Moreover, the analysis results of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy proved that there was only slight membrane fouling, which was mainly colloidal blocking caused by refractory organic compound.

Rhizospheric microorganisms are important for environmental conservancy. The constancy and variability of the microorganisms in the rhizosphere of Phragmites australis in relation to the spatiotemporal variations in wetland ecosystems were studied. During the peak and trough of the vegetative period of the Phragmites australis growing across the hydrologic gradients of the Sun Island Wetland, Biolog and denaturing gradient gel electrophoresis (DGGE) were used to investigate the rhizospheric microbial characteristics. Both methods demonstrated that the microbial activity, richness, and diversity decreased from summer to autumn. However, these properties did not show significant correlation with hydrologic gradient, except that the genetic richness and diversity of the fungi decreased with it. Cluster analysis also demonstrated that the rhizospheric microbial community seemed to be largely affected by a vegetative period. In addition, this research was extended to a broader range of determining the universal microorganisms, which showed notable adaptability.

In this paper, heavy metal adsorption by ceramsite with or without Bacillus subtilis (B. subtilis) immobilization was studied, and the synergetic effect of ceramsite and bacteria was discussed in detail. To investigate the roles of the micro-pore structure of ceramsite and bacteria in removing heavy metals, the amount of bacteria immobilized on the ceramsite was determined and the effect of pH was evaluated. It was found that the immobilization of B. subtilis on the ceramsite was attributed to the electrostatic attraction and covalent bond. The scanning electron microscopy results revealed that, with the presence of ceramsite, there was the conglutination of B. subtilis cells due to the cell outer membrane dissolving. In addition, the B. subtilis immobilized ceramsite showed a different adsorption capacity for different heavy metals, with the adsorption capacity ranking of La(3+) > Cu(2+) > Mg(2+) > Na(+).

We studied the flocculation behaviours of microbial communities in 21 soil, wastewater and activated sludge samples to clarify the effects of culture medium types on flocculation ability and screening efficiency, and to analyze diverse functions and microbial compositions. The bioflocculants produced by 33% of the microbial communities had flocculating efficiencies higher than 90%. Six out of the eight microbial communities with efficiencies over 94% were screened from the culture medium using dibutyl phthalate (DBP) as the carbon source. BF-BCT, which was derived from the Chinese cabbage soil sample, had the highest flocculating efficiency (99.6%), species diversity and uniformity. Nine highly efficient strains were separated and purified from seven different microbial communities, indicating that flocculating microorganisms are widely distributed in ecosystems. The 16S rRNA gene testing shows that the eight bacterial and the one fungal strains are common soil microorganisms. The flocculating abilities of BB11 (Sphingobacterium multivorum) and SE3 (Galactomyces geotrichum) have never been reported hitherto. Six strains, including the most flocculating-active TB13 and JB17, were screened from the culture medium using DBP as the sole carbon source. In particular, we compared the performance of culture media and analyzed analogous microbial communities with a Biolog automatic micro-analysis system for the first time.

Mineralization of Reactive Brilliant Red X-3B by a combined anaerobic-aerobic process which was inoculated with the co-culture of Penicillium sp. QQ and Exiguobacterium sp. TL was studied. The optimal conditions of decolorization were investigated by response surface methodology as follows: 132.67 g/L of strain QQ wet spores, 1.09 g/L of strain TL wet cells, 2.25 g/L of glucose, 2.10 g/L of yeast extract, the initial dye concentration of 235.14 mg/L, pH 6.5, and 33 °C. The maximal decolorization rate was about 96 % within 12 h under the above conditions. According to the Haldane kinetic equation, the maximal specific decolorization rate was 89.629 mg/g˙h. It was suggested that in the anaerobic-aerobic combined process, decolorization occurred in the anaerobic unit and chemical oxygen demand (COD) was mainly removed in the aerobic one. Inoculation of fungus QQ in the anaerobic unit was important for mineralization of X-3B. Besides, the divided anaerobic-aerobic process showed better performance of COD removal than the integrated one. It was suggested that the combined anaerobic-aerobic process which was inoculated with co-culture was potentially useful for the field application.

The process of simultaneous nitrification and denitrification (SND) of immobilized microorganisms in polyurethane form is discussed. The effect of different positions within the polyurethane carrier on microbial community response for the SND process is investigated by a combination of denaturing gradient gel electrophoresis profiles of the 16S rRNA gene V3 region and scanning electron microscopy. Results show that polyurethane, which consists of a unique porous structure, is an ideal platform for biofilm stratification of aerobe, anaerobe and facultative microorganisms in regard to the SND process. The community structure diversity response to different positions was distinct. The distributions of various functional microbes, detected from the surface aerobic stratification to the interior anaerobic stratification of polyurethane, were mainly nitrifying and denitrifying bacteria. Meanwhile aerobic denitrifying bacteria such as Paracoccus sp., Agrobacterium rubi and Ochrobactrum sp. were also adhered to the interior and surface of polyurethane. The SND process occurring on polyurethane foam was carried out by two independent processes: nitrogen removal and aerobic denitrification.

In order to strengthen the activity of biofilm on the carrier surface, the tourmpaline on polyurethane (TPU) carrier was prepared using waterborne polyurethane as medium. The physical properties of TPU carrier were characterized by scanning electron microscope(SEM) and water absorbency, and its effect on biofilm biomass and nitrifying ability was studied. The results showed that the tourmaline loading amount of TPU carrier can be affected by waterborne polyurethane. Tourmaline can optimize the number of polar groups of the TPU carrier and the pH of the nitrification condition. The amount of nitrobacteria and nitrate bacteria irreversibly adsorbed on the TPU carrier was increased by 74.82% and 71.89% , respectively. Correspondingly, the removing rate of NH+4 -N and NO-2 -N has risen by 8.12% and 9.08%, respectively, compared to the control without carrier. The TPU carrier was indicated to promote the nitrification.

The objective of this study was to investigate the potential ability of decolorizing Reactive Dark Blue K-R by the synergism of fungal strain Penicillium sp. QQ and bacterial strain Exiguobacterium sp. TL. The optimal conditions for decolorization determined by response surface methodology (RSM) were as follows: 12.5% (w/v) of both strains QQ and TL, 0.19% (w/v) of glucose, 0.09% (w/v) of yeast extract, pH7.0, 37 degrees C and 200mg/L of initial dye concentration. It was shown that about 97% of 200mg/L K-R could be decolorized within 24h under these conditions. Besides, strains QQ and TL co-cultures could decolorize 10 kinds of azo dyes effectively and be still 60% color removal when salinity increased to 15%. And most of the tested metal ions showed little influence on the decolorization except for Ni(2+). The results demonstrated that strains QQ and TL co-cultures could be useful for the practical bioremediation., (Copyright 2010 Elsevier Ltd. All rights reserved.)

To accelerate the start-up of biological municipal wastewater treatment processes at low temperatures and ensure their daily stable performances, bioaugmentation was adopted with the addition of specialized mixed bacteria. As a result, three types of biological processes were successfully started within 15days and showed stable and efficient daily performances. Results of PCR-DGGE analysis demonstrated the long-term predominance of the bioaugmented specialized bacteria in the bioaugmented systems. And results of BIOLOG analysis showed that the bacterial community structure and catabolic capability of the biological systems varied with wastewater temperature variations. However, the stability of the bacterial community under normal operating conditions and adaptability to perturbations enabled the long-term stable and efficient performances of the biological systems. In conclusion, bioaugmentation was successful for rapid start-up and stable performances of three typical biological municipal wastewater treatment processes at low temperatures., ((c) 2010 Elsevier Ltd. All rights reserved.)

In this study, decolorization of Reactive Brilliant Red X-3B wastewater by the biological process coping with high salinity and metal ions conditions was investigated, and 16S rDNA based fingerprint technique was used to investigate microbial population dynamics. Results of sequencing batch tests showed that the microbial community could keep efficient with high concentration of dye (1100 mg L(-1)), salt (150 g L(-1) NaCl) and some metal ions such as Mg(2+), Ca(2+) (1-10 mmol L(-1)) and Pb(2+) (1 mmol L(-1)). 16S rDNA-based molecular analysis techniques demonstrated that the microbial community shifted during the acclimatization process affected by salt or metal ions. Some stains similar to Bacillus, Sedimentibacter, Pseudomonas, Clostridiales, Streptomyces and some uncultured clones acted for the dynamic succession, supposed as potential decolorization bacteria. This study provided insights on the decolorization capability and the population dynamic shifts during decolorization process of azo dye wastewater coping with salt and metal ions.

Glass slides were hanged into a canal to acquire the ferrous-manganese oxidizing bacteria settled bio-film. Two isolated methods for ferrous-manganese oxidizing bacteria with special iron-manganese oxidizing matrix from the bio-film were tested. Element component of bacteria product and sheath structure of bacteria were analyzed. With two methods, plate cultivation and the novel semi-solid in situ cultivation method, strains belong to Family Leptothrix were isolated. XRF showed that the amorphous iron and manganese were two major metal elements of the precipitation formed by one strain of Leptothrix spp.. Through the microscope observation, one strain of Family Leptothrix was determined to form branch-like structured sheath, while another strain formed spider web-like structured sheath. Those isolated bacteria provide model strains for future testing of FISH probe and PCR primer of ferrous-manganese oxidizing bacteria.

Ecological filter was constructed to remedy Northern water in landscaping function. Nitrogen transition and its course in different recycling rate were studied by controlling the period. The action mechanism of landscaping water treated by compound substrate was analyzed deeply. Data showed that DO was improved from 7 to 11 and kept high when the recycling period was 1 hours and 1.5 hours. C/N was improved from 4-6 to 6-10. Removal ratios of NH4+ -N, NO2- -N and TN increased with recycling rate improving. Transition coefficients of NH4+ -N and NO2- -N were 0.885 3 and 0.968 5 under 1 hours and 1.5 hours period. The highest coefficient of NH4+ -N and NO2- -N was 0.942 4. Improving of recycling rate made the nitrification more rapidly and completely, and the transition approach of nitrogen was shortened. More rapid the recycling rate was, more direct was the transition.

Indole is an essential signal molecule in microbial studies. However, its ecological role in biological wastewater treatments remains enigmatic. This study explores the links between indole and complex microbial communities using sequencing batch reactors exposed to 0, 15, and 150 mg/L indole concentrations. A concentration of 150 mg/L indole enriched indole degrader Burkholderiales, while pathogens, such as Giardia , Plasmodium, and Besnoitia were inhibited at 15 mg/L indole concentration. At the same time, indole reduced the abundance of predicted genes in the "signaling transduction mechanisms" pathway via the Non-supervised Orthologous Groups distributions analysis. Indole significantly decreased the concentration of homoserine lactones, especially C 14 -HSL. Furthermore, the quorum-sensing signaling acceptors containing LuxR, the dCACHE domain, and RpfC showed negative distributions with indole and indole oxygenase genes. Signaling acceptors' potential origins were mainly Burkholderiales, Actinobacteria, and Xanthomonadales. Meanwhile, concentrated indole (150 mg/L) increased the total abundance of antibiotic resistance genes by 3.52 folds, especially on aminoglycoside, multidrug, tetracycline, and sulfonamide. Based on Spearman's correlation analysis, the homoserine lactone degradation genes which were significantly impacted by indole negatively correlated with the antibiotic resistance gene abundance. This study brings new insights into the effect of indole signaling on in biological wastewater treatment plants. • Indole exposure inhibited conditional protozoa pathogens in SBR systems. • Quorum-sensing signaling acceptors negative correlated with indole oxygenase. • Concentrated indole increased antibiotic resistance genes abundance by 3.52 folds. [ABSTRACT FROM AUTHOR]

To reduce fermentation costs and achieve continuous fermentation of bio-flocculant, the immobilized fermentation to produce bioflocculant was used. The performances of the carriers including activated carbon, pllyurethane foam and mycelial pellets were contrasted by comparing the carrier stability, bio-flocculant production and bio-flocculant activity. The solid-liquid ratio of activated carbon and mycelial pellets were optimized. The results show that the activated carbon, polyurethane foam and mycelial pellets could adsorb bioflocculant-producing bacteria F + and retain high flocculanting activity for long time. The yields of activated carbon and mycelial pellets were higher than that of polyurethane foam. The adsorption rate of mycelial pellets in 24 h was higher than that of granular activated carbon. Under the optimized conditions (solid-liquid ratio 1.0 g/L; the fermentation time 24 h ), the crude bio-flocculant yield of immobilized fermentation by mycelial pellets (2. 234 g/L) increased 14%. The shake flask experiments show that the three carriers could produce bioflocculant more than 15 batches. The solid-liquid ration was optimized as 1.0 g/L by considering the flocculation rate and cost. [ABSTRACT FROM AUTHOR]

To improve demulsifying property, the original biodemulsifier-producing bacterium, Bacillus mojavensis XH1, was mutated and bred by the combined treatment method using UV irradiation and niitrosoguanidine (NTG). A high efficient biodemulsifier-producing mutant XN5 with the better stability was obtained after continuous passages. The optimal cultural conditions were as follows: the mixture of 10 g/L glucose and 4 % liquid paraffin is the carbon source, the mixture of 4.0 g/L NH4Cl and 1.0 g/L yeast extract is nitrogen source, pH =6. 5 , the rotating rate is 140 r/min and the incubated time is 24 h. The 12 h and 24 h demulsification ratios of the mutant XN5 were 94. 17% and 98. 67% , which were 64. 81% and 15. 12% higher than that of the original strain XH1, respectively. [ABSTRACT FROM AUTHOR]

To find a method of microbial immobilization which was efficient, fast and applied to biomass carrier mycelial pellet, bacteria JH -9 were immobilized onto mycelial pellet formed by Aspergillus Y3. And the characteristics and internal structure of two different immobilization methods were compared. The simultaneity culture immobilization method could immobilize more bacteria and with little time with same bacteria inoculation count. Moreover, the volume and quantity of combined mycelial pellets formed by simultaneity culture immobilization method were bigger than that by adsorption immobilization method, and its diameter ,weight and relative density were smaller. To immobilize with the same method, the size and volume of combined mycelial pellets were in direct proportion to the inoculation count of engineering bacteria, whereas its weight and relative density were opposite. Bacteria were immobilized and grew on each mycelium of combined mycelium pellets formed by simultaneity culture immobilization method. [ABSTRACT FROM AUTHOR]

Six strains with flocculent characteristic have been screened from oil - field wastewater, which are named as F1, F2, F3, F4, F5 and F6. They were identified and classified by 16SrDNA sequence. The flocculation species were analyzed through UV and IR scanning spectrophotometry. It is showed that the six strains belong to the same species with Balillus sp., Agrobacterlum sp., and Kocurla sp. and they have 99% homogeneous identity. The results of flocculent efficiency show that the flocculent efficiency of the six strains is more than 69%, among which the flocculent efficiencies of F2, F3, F5 and F6 are more than 80%. Mixed cultures were conducted pairwise among F2, F3, F5 and F6, and the results show that the combination of F2 and F6 strains exhibits the best flocculating efficiency and it is higher than that of any pure strain. [ABSTRACT FROM AUTHOR]

Abstract: The biodegradation of polycyclic aromatic hydrocarbons (PAHs) (8.15mg PAHskg−1 soil) in aged contaminated soil by isolated microbial consortium (five fungi and three bacteria) during the incubation of 64d is reported. The applied treatments were: (1) biodegradation by adding microbial consortium in sterile soils (BM); (2) biodegradation by adding microbial consortium in non-sterile soils (BMN); and (3) biodegradation by in situ “natural” microbes in non-sterile soils (BNN). The fungi in BM and BMN soils grew rapidly 0–4d during the incubation and then reached a relative equilibrium. In contrast the fungi in BNN soil remained at a constant level for the entire time. Comparison with the fungi, the bacteria in BNN soils grew rapidly during the incubation 0–2d and then reached a relative equilibrium, and those in BM and BMN soils grew slowly during the incubation of 64d. After 64d of incubation, the PAH biodegradations were 35%, 40.7% and 41.3% in BNN, BMN and BM, respectively. The significant release of sequestrated PAHs in aged contaminated soil was observed in this experiment, especially in the BM soil. Therefore, although bioaugmentation of introduced microbial consortium increased significantly the biodegradation of PAHs in aged contaminated soil with low PAH concentration, the creation of optimum of the environmental situation might be the best way to use bioremediation successfully in the field. [Copyright &y& Elsevier]