Draft Genome Sequences of Three
            <i>Bacillus</i>
            Species Isolated from Biofouled Reverse-Osmosis Membranes

Rehman, Zahid Ur; Iftikhar, Muhammad Ali; Leiknes, TorOve

doi:10.1128/mra.00413-20

Cited by 2 publications

(4 citation statements)

References 10 publications

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“…However, Bacillus cereus was found on the P2 membrane after cleaning ( Table 3 ), presumably due to cross-contamination during the experimental process. Previous reports revealed that Bacillus subtilis and Bacillus aquimaris were mostly isolated from RO membranes [ 15 , 51 , 52 ]. The difference between our study could be explained by the difference in environmental and cleaning conditions.…”

Section: Resultsmentioning

confidence: 99%

Autopsy of Used Reverse Osmosis Membranes from the Largest Seawater Desalination Plant in Oman

et al. 2022

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The Barka desalination plant, commissioned in 2018, is the largest desalination plant in Oman. It has a capacity of 281 MLD with a reverse osmosis (RO) first-pass recovery rate of 46%. As part of the standard operator practice, a membrane autopsy was conducted to determine the cause of reductions in membrane performance. This study investigated fouled membranes (model No. SW30HRLE-440) from two different locations in the membrane rack. Various analytical methods were used to conduct the membrane autopsy. Field-emission scanning electron microscopy/energy-dispersive X-ray (FESEM/EDS) analyses of membrane samples showed major components of inorganic foulants. Moreover, black and salt-like crystals deposited on the membrane surface revealed significant carbon (C) components and oxygen (O), with a small amount of magnesium (mg), chloride (Cl), sodium (Na), aluminium (Al), and calcium (Ca), respectively. A Fourier transform infrared (FTIR) analysis revealed the presence of long-chain hydrocarbons, carboxylic acids/esters, carbohydrates/polysaccharides, and inorganic foulants. Thermogravimetric analyses (TGA) of the membranes showed a high initial weight loss due to organic and inorganic fouling. X-ray photoelectron (XPS) analyses further confirmed the presence of inorganic and organic foulants on the membrane surfaces. Bacteria identification results showed the presence of Bacillus cereus and Bacillus marisflavi. This paper offers a detailed analysis of the foulants present on the reverse osmosis membrane surface and sub-surface before and after a cleaning process.

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Section: Resultsmentioning

confidence: 99%

Autopsy of Used Reverse Osmosis Membranes from the Largest Seawater Desalination Plant in Oman

et al. 2022

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“…The basic statistics of the assembled genomes of RO1, RO2 and RO3 are given in Supplementary Table 1 and in Rehman et al (2020b) . Briefly, the sizes of genomes were between 4.1 and 4.2 Mbp, with completeness more than 98%.…”

Section: Resultsmentioning

confidence: 99%

“…Genome analyses reveal that only RO3 contain the genes that encode proteins similar to TasA, TapA, and SipW ( Supplementary Table 4 ). The absence of TasA, TapA, and SipW similar proteins in RO1 and RO2 could result from incomplete genome sequences, as the genome sequences of RO1 and RO2 are 98.56% complete, whereas RO3 is 98.85% complete ( Rehman et al, 2020b ). Another possibility is that RO1 and RO2 produce functionally similar proteins with different primary sequences that could not be identified by blastp analysis.…”

Section: Resultsmentioning

confidence: 99%

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Physicochemical Properties of Extracellular Polymeric Substances Produced by Three Bacterial Isolates From Biofouled Reverse Osmosis Membranes

2021

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This work describes the chemical composition of extracellular polymeric substances (EPS) produced by three bacteria (RO1, RO2, and RO3) isolated from a biofouled reverse osmosis (RO) membrane. We isolated pure cultures of three bacterial strains from a 7-year-old biofouled RO module that was used in a full-scale seawater treatment plant. All the bacterial strains showed similar growth rates, biofilm formation, and produced similar quantities of proteins and polysaccharides. The gel permeation chromatography showed that the EPS produced by all the strains has a high molecular weight; however, the EPS produced by strains RO1 and RO3 showed the highest molecular weight. Fourier Transform Infrared Spectroscopy (FTIR), Proton Nuclear Magnetic Resonance (1H NMR), and Carbon NMR (13C NMR) were used for a detailed characterization of the EPS. These physicochemical analyses allowed us to identify features of EPS that are important for biofilm formation. FTIR analysis indicated the presence of α-1,4 glycosidic linkages (920 cm–1) and amide II (1,550 cm–1) in the EPS, the presence of which has been correlated with the fouling potential of bacteria. The presence of α-glycoside linkages was further confirmed by 13C NMR analysis. The 13C NMR analysis also showed that the EPS produced by these bacteria is chemically similar to foulants obtained from biofouled RO membranes in previous studies. Therefore, our results support the hypothesis that the majority of substances that cause fouling on RO membranes originate from bacteria. Investigation using 1H NMR showed that the EPS contained a high abundance of hydrophobic compounds, and these compounds can lead to flux decline in the membrane processes. Genome sequencing of the isolates showed that they represent novel species of bacteria belonging to the genus Bacillus. Examination of genomes showed that these bacteria carry carbohydrates-active enzymes that play a role in the production of polysaccharides. Further genomic studies allowed us to identify proteins involved in the biosynthesis of EPS and flagella involved in biofilm formation. These analyses provide a glimpse into the physicochemical properties of EPS found on the RO membrane. This knowledge can be useful in the rational design of biofilm control treatments for the RO membrane.

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Draft Genome Sequences of Three Bacillus Species Isolated from Biofouled Reverse-Osmosis Membranes

Cited by 2 publications

References 10 publications

Autopsy of Used Reverse Osmosis Membranes from the Largest Seawater Desalination Plant in Oman

Autopsy of Used Reverse Osmosis Membranes from the Largest Seawater Desalination Plant in Oman

Physicochemical Properties of Extracellular Polymeric Substances Produced by Three Bacterial Isolates From Biofouled Reverse Osmosis Membranes

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