Biofouling reduction in a MBR by the application of a lytic phage on a modified nanocomposite membrane

Ayyaru, Sivasankaran,Choi, Jeongdong,Ahn, Young-Ho The Royal Society of Chemistry 2018 Environmental science Vol.4 No.10

<P>Biological contamination of membranes is an unavoidable problem in membrane bioreactor (MBR) systems. In addition, biofouling caused by antibiotic resistant bacteria (ARB) has become a critical issue not only for environmental health but also for the operation of membrane processes. This paper highlights the potential applications of lytic phage therapy on a modified nanocomposite membrane (polyvinylidene fluoride (PVDF)-sulfonated graphene oxide (SGO)) to control bacterial fouling on membranes and ARB in MBRs. An antibiotic resistant bacterium (E2) and a respective phage (P2) were isolated from municipal wastewater and used in a MBR system as a membrane foulant and antifoulant, respectively. The isolated bacteria were screened further for antibiotic susceptibility and the minimum inhibitory concentrations (MICs) were determined. E2 was found to be resistant to various concentrations of ampicillin, cefotaxime, vancomycin, tetracycline, and gentamicin. The phage treatment efficiency was examined by membrane flux. In the nanocomposite membrane, the E2 + P2 suspension showed a much higher flux (125 L m<SUP>−2</SUP> h<SUP>−1</SUP>) than the E2 suspension (60 L m<SUP>−2</SUP> h<SUP>−1</SUP>). Up to 57% higher flux was observed in the phage treatment, suggesting that the lytic phage prevented bacterial multiplication and biofilm formation. The multiplicity of infection (MOI) was examined to determine the optimal number of phages required to kill the bacteria. Scanning electron microscopy (SEM) was used to observe the bacterial infection and biofouling reduction due to the phage treatment. The modified nanocomposite membrane was aimed at protein fouling reduction (pore blocking resistance) and lytic phage addition was aimed at bacterial fouling reduction (cake layer resistance). The different types of fouling resistance of the membrane were estimated to distinguish between phage treatment and modified membrane efficiency. Based on the results of fouling resistance and SEM, the phage could reduce the membrane cake layer resistance and the modification of the membrane reduced the pore blocking resistance. The synergistic combination of phage treatment and the modified membrane reduced both types of biofouling. A separate cleaning system was installed and examined to avoid disturbing the normal MBR process (killing of bacteria in the feed solution by the phages).</P>

Fabrication and separation performance of polyethersulfone/sulfonated TiO₂ (PES–STiO₂) ultrafiltration membranes for fouling mitigation

Ayyaru, Sivasankaran,Ahn, Young-Ho THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.67 No.-

<P><B>Abstract</B></P> <P>Polyethersulfone (PES)/sulfonated TiO<SUB>2</SUB> (STiO<SUB>2</SUB>) nanoparticles (NPs) UF blended membranes were fabricated with different loadings of STiO<SUB>2</SUB>. The modified membranes exhibited significant improvement in surface roughness, porosity, and pore size when compared to the PES membrane. The P-STiO<SUB>2</SUB> 1 and P-TiO<SUB>2</SUB> 1 blended membranes exhibited higher water flux, approximately 102.4% and 62.6%, respectively, compared to PES. SPP-STiO<SUB>2</SUB> and P-STiO<SUB>2</SUB> showed lower Rir fouling resistance than the P-TiO<SUB>2</SUB> blended membrane. Overall, the STiO<SUB>2</SUB>-blended membranes provide high hydrophilicity permeability, anti-fouling performance, and improved BSA rejection attributed to the hydrogen bonding force and more electrostatic repulsion properties of STiO<SUB>2</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new hydrophilic surface-modified additive, sulfonated TiO<SUB>2</SUB>, was prepared. </LI> <LI> The PES/STiO<SUB>2</SUB> modified UF membranes were prepared via phase inversion method. </LI> <LI> For the P-STiO<SUB>2</SUB>, 102.4% showed higher water flux compared to PES membrane. </LI> <LI> The STiO<SUB>2</SUB> membranes showed lower Rir fouling resistance of 3.4% than TiO<SUB>2</SUB> (23.2%). </LI> <LI> –SO<SUB>3</SUB>H group in the STiO<SUB>2</SUB> has a stronger hydrophilic group, than to the TiO<SUB>2</SUB>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Fabrication and separation performance of polyethersulfone/ sulfonated TiO2 (PES–STiO2) ultrafiltration membranes for fouling mitigation

Sivasankaran Ayyaru,안영호 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.67 No.-

Polyethersulfone (PES)/sulfonated TiO2 (STiO2) nanoparticles (NPs) UF blended membranes were fabricated with different loadings of STiO2. The modified membranes exhibited significant improvement in surface roughness, porosity, and pore size when compared to the PES membrane. The P-STiO2 1 and P-TiO2 1 blended membranes exhibited higher water flux, approximately 102.4% and 62.6%, respectively, compared to PES. SPP-STiO2 and P-STiO2 showed lower Rir fouling resistance than the P-TiO2 blended membrane. Overall, the STiO2-blended membranes provide high hydrophilicity permeability, anti-fouling performance, and improved BSA rejection attributed to the hydrogen bonding force and more electrostatic repulsion properties of STiO2.

Real-time PCR Quantification of White Spot Syndrome Virus (WSSV) and Hepatopancreatic Parvovirus (HPV) Loads in Shrimp and Seawaters of Shrimp Ponds on the West Coast of South Korea

장인권,Ayyaru Gopalakannan,Kannan Suriakala,김종식,김봉래,조영록,Xian-Hong Meng,서형철 한국수산과학회 2008 Fisheries and Aquatic Sciences Vol.11 No.4

Viral diseases are major emerging problems of shrimp that have affected the production, and even complete losses for shrimp farms. In this study, we developed a sensitive TaqMan real-time PCR method to quantify white spot syndrome virus (WSSV) and hepatopancreatic parvovirus (HPV) in the shrimp and pond water in which fleshy shrimp, Fenneropenaeus chinensis, and Pacific white shrimp, Litopenaeus vannamei, are reared. WSSV and HPV in pond seawaters ranged from 1.65×103 to 2.43×109 and from 0 to 4.43×105 copies/L of seawater, respectively. Of 20 ponds analyzed, all pond water and shrimp were positive for WSSV. L. vannamei showed higher susceptibility to WSSV than F. chinensis. HPV was detected only in the pond water for F. chinensis. In shrimp tissue, however, HPV was found in both species, with 23-times higher infection rate in F. chinensis than L. vannamei. The total bacterial counts in the pond water ranged from 2.23×103 to 1.98×105 CFU/mL. The variations in total bacterial count for each pond appeared to correlate to the variations of the WSSV load. Statistical analysis indicated that there was no significant difference (P>0.05) between the WSSV load in pond water and shrimp, and there was no relationship between total bacterial load and viral load in the pond water. However, a significant difference (P<0.01) was found between HPV load and L. vannamei and F. chinensis pond water.

Non-toxic properties of TiO₂ and STiO₂ nanocomposite PES ultrafiltration membranes for application in membrane-based environmental biotechnology

Pandiyan, Rajesh,Ayyaru, Sivasankaran,Ahn, Young-Ho Elsevier 2018 Ecotoxicology and environmental safety Vol.158 No.-

<P><B>Abstract</B></P> <P>In membrane bioreactor (MBR) technology, nanocomposite membrane has a great potential to improve the filtration performance and antifouling. However, antibacterial activity of nanoparticles (NPs) is a significant disadvantage which can be impacted to bacterial growth and microbial community in MBRs. The modified polyethersulfone (PES) ultrafiltration (UF) membranes in the study were prepared by using TiO<SUB>2</SUB> NPs and TiO<SUB>2</SUB> NPs functionalized with sulfonation (STiO<SUB>2</SUB>). The antibacterial effect of NPs and non-toxic properties of nanocomposite membranes were examined by using three different Gram-negative bacterial species isolated from a local full scale membrane bioreactor treating municipal wastewater (<I>Escherichia coli, Pantoea agglomerans</I>, and <I>Pseudomonas graminis</I>). Results are revealed that the TiO<SUB>2</SUB> and STiO<SUB>2</SUB> NPs have 60% of antibacterial activity based on disc diffusion, viability tests, and TEM analysis. However, the PES-TiO<SUB>2</SUB> and PES-STiO<SUB>2</SUB> nanocomposite UF membranes showed significantly lower antibacterial activity (<95%, significance at <I>p</I> < 0.0001), indicating innocuous to bacterial growth. This study highlights that the PES-TiO<SUB>2</SUB> and PES-STiO<SUB>2</SUB> nanocomposite membrane is more sustainable than PES membrane and promising materials for MBRs, by taking advantage of non-toxic properties to bacterial growth.</P> <P><B>Highlights</B></P> <P> <UL> <LI> TiO<SUB>2</SUB> and STiO<SUB>2</SUB> NPs showed 60% of antibacterial activity in all three bacterial species. </LI> <LI> PES-TiO<SUB>2</SUB> and -STiO<SUB>2</SUB> membranes revealed 95% non-toxic in bacterial cell viability test. </LI> <LI> PES-TiO<SUB>2</SUB> and -STiO<SUB>2</SUB> UF membranes are sustainable materials for MBR system. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Application of graphene-based nanomaterials as novel cathode catalysts for improving power generation in single chamber microbial fuel cells

Valipour, A.,Ayyaru, S.,Ahn, Y. Elsevier Sequoia 2016 Journal of Power Sources Vol.327 No.-

The low catalytic activity, limited resources, complexity and costs, and non-environmentally friendly nature are key factors limiting the application of non-precious metals and their composites at the cathode in microbial fuel cells (MFCs). This study evaluated the feasibility of graphene-based nanomaterials (RGO<SUB>HI-AcOH</SUB> vs. RGO/Ni nanoparticle composite) as novel cathode catalysts in single chamber air-cathode MFCs. A series of MFCs with different catalyst loadings were produced. The electrochemical behavior of the MFCs were evaluated by cyclic voltammetry (CV) and impedance spectroscopy (EIS). As a result, the MFCs with the RGO<SUB>HI-AcOH</SUB> cathodes showed greater maximum power densities (>37%) than those with the RGO/Ni nanoparticle cathodes. In the MFCs, the highest maximum power density of 1683 +/- 23 mW/m<SUP>2</SUP> (CE = 72 +/- 3%), which covers 77% of that estimated for Pt/C (2201 +/- 45 mW/m<SUP>2</SUP>, CE = 81 +/- 4%), was obtained from the double loading RGO<SUB>HI-AcOH</SUB> cathodes. Among the MFCs with the RGO/Ni nanoparticle composite cathodes, those loaded with a double catalyst (1015 +/- 28 mW/m<SUP>2</SUP>, CE = 70 +/- 2%) showed better power performance than the others. Both CV and EIS showed good agreement with the MFC results. This study suggests that the RGO<SUB>HI-AcOH</SUB> cathode, particularly with a double catalyst loading, is promising for sustainable low-cost green materials, stable power generation and the long-term operation of MFCs.

Enhanced cathode performance of a rGO-V₂O₅ nanocomposite catalyst for microbial fuel cell applications

Mahalingam, Shanmugam,Ayyaru, Sivasankaran,Ahn, Young-Ho The Royal Society of Chemistry 2018 Dalton transactions Vol.47 No.46

<P>A reduced graphene oxide-V2O5 nanocomposite was synthesized by a low temperature surfactant free hydrothermal method and its MFC performance was assessed. The structural properties of the synthesized nanocomposite were studied by X-ray diffraction. Field emission scanning electron microscopy of the nanocomposite revealed a wrinkled paper-like structure of rGO and a nanobelt-like structure of V2O5. This study estimated the viability of the graphene-based nanocomposite rGO-V2O5 as a novel cathode catalyst in single chamber air-cathode MFCs. A series of MFCs with different catalyst loadings were produced. The electrochemical behavior of the MFCs was calculated by cyclic voltammetry. The MFCs with the rGO-V2O5 nanocomposite cathode exhibited superior maximum power densities (83%) to those with the pure V2O5 cathodes. The rGO-V2O5 with a double-loaded nanocomposite catalyst achieved an enhanced power density of 1668 ± 11 mW m<SUP>−2</SUP> and an OCP of 698 ± 4 mV, which was 83% of that estimated for the Pt/C 2004 ± 15 mW m<SUP>−2</SUP> nanocomposite cathode. The significant increase in power density suggests that the reduced graphene oxide-V2O5 nanocomposite is a promising material for MFC applications. The CV result showed good agreement with the MFC result. The prepared rGO-V2O5 nanocomposite cathode, particularly with a double loading catalyst, is promising as a sustainable low-cost green material for stable power generation and long-term operation of MFCs.</P>

Real-Times PCR Quantification of White Spot Syndrome Virus (WSSV) and Hepatopancreatic Parvovirus (HPV) Loads in Shrimp and Seawaters of Shrimp Ponds on the West Coast of South Korea

( In Kwon Jang ),( Ayyaru Gopalakannan ),( Kannan Suriakala ),( Jong Sheek Kim ),( Bong Rae Kim ),( Yeong Rok Cho ),( Xian Hong Meng ),( Hyeong Chul Seo ) 한국수산학회 2008 Fisheries and Aquatic Sciences Vol.11 No.4

Real-time PCR Quantification of White Spot Syndrome Virus (WSSV) and Hepatopancreatic Parvovirus (HPV) Loads in Shrimp and Seawaters of Shrimp Ponds on the West Coast of South Korea

Jang, In-Kwon,Gopalakannan, Ayyaru,Suriakala, Kannan,Kim, Jong-Sheek,Kim, Bong-Rae,Cho, Yeong-Rok,Meng, Xian-Hong,Seo, Hyeong-Chul The Korean Society of Fisheries and Aquatic Scienc 2008 Fisheries and Aquatic Sciences Vol.11 No.4

Viral diseases are major emerging problems of shrimp that have affected the production, and even complete losses for shrimp farms. In this study, we developed a sensitive TaqMan real-time PCR method to quantify white spot syndrome virus (WSSV) and hepatopancreatic parvovirus (HPV) in the shrimp and pond water in which fleshy shrimp, Fenneropenaeus chinensis, and Pacific white shrimp, Litopenaeus vannamei, are reared. WSSV and HPV in pond seawaters ranged from $1.65{\times}10^3$ to $2.43{\times}10^9$ and from 0 to $4.43{\times}10^5$ copies/L of seawater, respectively. Of 20 ponds analyzed, all pond water and shrimp were positive for WSSv. L. vannamei showed higher susceptibility to WSSV than F chinensis. HPV was detected only in the pond water for F chinensis. In shrimp tissue, however, HPV was found in both species, with 23-times higher infection rate in F chinensis than L. vannamei. The total bacterial counts in the pond water ranged from $2.23{\times}l0^3$ to $1.98{\times}l0^5\;CFU/mL$. The variations in total bacterial count for each pond appeared to correlate to the variations of the WSSV load. Statistical analysis indicated that there was no significant difference (P>0.05) between the WSSV load in pond water and shrimp, and there was no relationship between total bacterial load and viral load in the pond water. However, a significant difference (P<0.01) was found between HPV load and L. vannamei and F chinensis pond water.

사육수 비교환 방식에 의한 흰다리새우의 고밀도 사육 I. 후기유생(postlarva)의 실내 중간육성

장인권,김종식,조국진,서형철,조영록,Ayyaru Gopalakannan,김봉래 한국양식학회 2008 韓國養殖學會誌 Vol.21 No.4

Farming of the fleshy shrimp Fenneropenaeus chinensis which is a major cultured species in the west coast of South Korea, has been suffered from mass mortality due to disease epizootics including viruses. Since the Pacific white shrimp Litopenaeus vannamei was introduced to Korea in 2003, farming of this species has rapidly increased for years, occupying 62.5% of total cultured shrimp production in 2007. However the studies on L. vannamei culture methods for shrimp farming situations in Korea are very limited. Nursery culture of shrimp larvae has some advantages including increased survival, improved feed efficiencies, enhanced growth performance and reduced grow-out period. In this study, L. vannamei postlarvae (PL3-PL10) with a density of 3,750-9,090/m3 were cultured in four raceways under limited water exchange condition for 35 days. Survival was the highest (93.6%) in tank stocked with 4,090/m3 and was the lowest in tank with 9,090/m3(58.1%). Mean body weight at harvest ranged from 0.071 to 0.108 g, and FCR was 0.59-0.70 in all tanks. Concentration of total ammonia nitrogen was increased up to 20 ppm on day 10 in all tanks and thereafter gradually decreased by the third week of culture. Nitrite-nitrogen was rapidly increased from the third week, representing bio-floc condition by developed nitrifying bacterial community. Of the present nursery system some modification of structure and consideration for commercial scale are needed in order to be implemented to shrimp farmers.