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Evaluation of Tangential Flow Filtration for the Concentration and Separation of Bacteria and Viruses in Contrasting Marine Environments.

Cai L, Yang Y, Jiao N, Zhang R - PLoS ONE (2015)

Bottom Line: Estuary samples showed significantly higher percentages of bacterial retention than nearshore and ocean samples.For virus-size membranes, a higher viral recovery and lower sorption was observed for regenerated cellulose membrane than PES membranes in the small-scale TFF.Similar viral recoveries were observed between PES membranes in the large-scale TFF, with higher viral concentrations being observed in estuary samples than in nearshore samples.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, Xiamen University (Xiang'an), Xiamen, Fujian, 361102, China.

ABSTRACT
Tangential flow filtration (TFF), which has been widely adopted to concentrate a diverse array of microbes from water, is a promising method of microbial separation or removal. However, it is essential to select an optimal membrane suitable for the specific filtration application. This study evaluated two different scales of TFF systems for concentrating and separating microbes (including bacteria and viruses) from contrasting marine waters. Among bacteria-size membranes, polyvinylidene difluoride (PVDF) membranes showed higher bacterial recovery, but lower viral permeation efficiencies than polyethersulfone (PES) membranes, regardless of environments and scales of TFF. Estuary samples showed significantly higher percentages of bacterial retention than nearshore and ocean samples. For virus-size membranes, a higher viral recovery and lower sorption was observed for regenerated cellulose membrane than PES membranes in the small-scale TFF. Similar viral recoveries were observed between PES membranes in the large-scale TFF, with higher viral concentrations being observed in estuary samples than in nearshore samples. Deep ocean samples showed the lowest recovery of viruses, which was consistent with observations of bacterial recovery. Synthetically, PVDF may be more suitable for the concentration of bacterial cells, while PES would be a better choice for the collection of viruses. When compared with the PES membrane, regenerated cellulose is better for viral concentration, while PES is recommended to obtain bacteria- and virus-free seawater.

No MeSH data available.


Related in: MedlinePlus

Efficiencies of viral filtration by three 30 kDa membranes for samples from contrasting marine environments in small-scale TFF(A). Comparison of viral filtration by Millipore and Pall 30 kDa cut-off membranes (B) and for samples from contrasting marine environments using Millipore 30 kDa cut-off membrane (C) in large-scale TFF.Error bars depict the standard error of the mean expressed in percentage. *, p <0.05; **, p<0.01.
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pone.0136741.g006: Efficiencies of viral filtration by three 30 kDa membranes for samples from contrasting marine environments in small-scale TFF(A). Comparison of viral filtration by Millipore and Pall 30 kDa cut-off membranes (B) and for samples from contrasting marine environments using Millipore 30 kDa cut-off membrane (C) in large-scale TFF.Error bars depict the standard error of the mean expressed in percentage. *, p <0.05; **, p<0.01.

Mentions: Removal of bacterial cells using 0.22 μm and 1000 kDa membranes is always the first step to obtain viral concentrations in aquatic viral ecology studies in which low retention, low sorption, and high permeation of viruses are desired. We observed a higher retention and lower permeation of viruses for PVDF membranes than PES membranes in large- and small-scale TFF (Figs 3B and 4B), indicating that PES membranes may be a better choice if more viruses are desired. The filtration capacities of three 30 kDa cut-off membranes with different materials or manufacturers (RCL, Millipore; PES, Millipore; PES, Pall) for viral particles with small-scale TFF were shown in Fig 6A. Generally, 30 kDa cut-off membranes show 12.48–49.57% recovery rates of viruses, which is similar to previous studies [25,26]. The viral recovery efficiency of the RCL membrane (average 35.28%) was higher than that of the two PES membranes (average 19.00% and 23.32%, respectively). In addition, the fraction of viruses that permeate through the membranes was higher for RCL (average 21.26%) than for PES membranes (average 15.76% and 14.36%, respectively), indicating a higher removal rate of viruses with PES membranes. No significant differences were observed in the levels of viruses in the retentate and permeate between the two PES membranes. In large-scale TFF, similar viral recovery efficiencies of 40.82% and 39.60% were observed for the PES membranes manufactured by Millipore and Pall, respectively (Fig 6B). There were also no significant differences in viral filtration (average 3.81% and 3.75%) between these two PES membranes.


Evaluation of Tangential Flow Filtration for the Concentration and Separation of Bacteria and Viruses in Contrasting Marine Environments.

Cai L, Yang Y, Jiao N, Zhang R - PLoS ONE (2015)

Efficiencies of viral filtration by three 30 kDa membranes for samples from contrasting marine environments in small-scale TFF(A). Comparison of viral filtration by Millipore and Pall 30 kDa cut-off membranes (B) and for samples from contrasting marine environments using Millipore 30 kDa cut-off membrane (C) in large-scale TFF.Error bars depict the standard error of the mean expressed in percentage. *, p <0.05; **, p<0.01.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4549332&req=5

pone.0136741.g006: Efficiencies of viral filtration by three 30 kDa membranes for samples from contrasting marine environments in small-scale TFF(A). Comparison of viral filtration by Millipore and Pall 30 kDa cut-off membranes (B) and for samples from contrasting marine environments using Millipore 30 kDa cut-off membrane (C) in large-scale TFF.Error bars depict the standard error of the mean expressed in percentage. *, p <0.05; **, p<0.01.
Mentions: Removal of bacterial cells using 0.22 μm and 1000 kDa membranes is always the first step to obtain viral concentrations in aquatic viral ecology studies in which low retention, low sorption, and high permeation of viruses are desired. We observed a higher retention and lower permeation of viruses for PVDF membranes than PES membranes in large- and small-scale TFF (Figs 3B and 4B), indicating that PES membranes may be a better choice if more viruses are desired. The filtration capacities of three 30 kDa cut-off membranes with different materials or manufacturers (RCL, Millipore; PES, Millipore; PES, Pall) for viral particles with small-scale TFF were shown in Fig 6A. Generally, 30 kDa cut-off membranes show 12.48–49.57% recovery rates of viruses, which is similar to previous studies [25,26]. The viral recovery efficiency of the RCL membrane (average 35.28%) was higher than that of the two PES membranes (average 19.00% and 23.32%, respectively). In addition, the fraction of viruses that permeate through the membranes was higher for RCL (average 21.26%) than for PES membranes (average 15.76% and 14.36%, respectively), indicating a higher removal rate of viruses with PES membranes. No significant differences were observed in the levels of viruses in the retentate and permeate between the two PES membranes. In large-scale TFF, similar viral recovery efficiencies of 40.82% and 39.60% were observed for the PES membranes manufactured by Millipore and Pall, respectively (Fig 6B). There were also no significant differences in viral filtration (average 3.81% and 3.75%) between these two PES membranes.

Bottom Line: Estuary samples showed significantly higher percentages of bacterial retention than nearshore and ocean samples.For virus-size membranes, a higher viral recovery and lower sorption was observed for regenerated cellulose membrane than PES membranes in the small-scale TFF.Similar viral recoveries were observed between PES membranes in the large-scale TFF, with higher viral concentrations being observed in estuary samples than in nearshore samples.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, Xiamen University (Xiang'an), Xiamen, Fujian, 361102, China.

ABSTRACT
Tangential flow filtration (TFF), which has been widely adopted to concentrate a diverse array of microbes from water, is a promising method of microbial separation or removal. However, it is essential to select an optimal membrane suitable for the specific filtration application. This study evaluated two different scales of TFF systems for concentrating and separating microbes (including bacteria and viruses) from contrasting marine waters. Among bacteria-size membranes, polyvinylidene difluoride (PVDF) membranes showed higher bacterial recovery, but lower viral permeation efficiencies than polyethersulfone (PES) membranes, regardless of environments and scales of TFF. Estuary samples showed significantly higher percentages of bacterial retention than nearshore and ocean samples. For virus-size membranes, a higher viral recovery and lower sorption was observed for regenerated cellulose membrane than PES membranes in the small-scale TFF. Similar viral recoveries were observed between PES membranes in the large-scale TFF, with higher viral concentrations being observed in estuary samples than in nearshore samples. Deep ocean samples showed the lowest recovery of viruses, which was consistent with observations of bacterial recovery. Synthetically, PVDF may be more suitable for the concentration of bacterial cells, while PES would be a better choice for the collection of viruses. When compared with the PES membrane, regenerated cellulose is better for viral concentration, while PES is recommended to obtain bacteria- and virus-free seawater.

No MeSH data available.


Related in: MedlinePlus