Mitigation of biofouling in membrane bioreactors by quorum-quenching bacteria during the treatment of metal-containing wastewater.

Quorum quenching (QQ) is an efficient way to mitigate membrane biofouling in a membrane bioreactor (MBR) during wastewater treatment. A QQ bacterium, Lysinibacillus sp. A4, was isolated and used to mitigate biofouling in an MBR during the treatment of wastewater containing metals.

Characterization of an N-acylhomoserine lactonase from Serratia sp. and its biofouling mitigation in a membrane bioreactor.

Membrane biofouling is a process that can impede the development of membrane bioreactor (MBR), which constitutes an important system of the wastewater treatment process. Membrane biofouling is governed by quorum sensing (QS), a communication system heavily dependent on the activities of signal molecules. Certain bacteria, known as quorum quenching (QQ) bacteria, can quench the QS process by destroying the signal molecules.

Biotreatment of Cr(VI) and pyrene combined water pollution by loofa-immobilized bacteria.

Hexavalent chromium (Cr(VI)) and pyrene are toxic pollutants that are difficult to remediate from soils and wastewater. Serratia sp. strains have been previously demonstrated to remove either Cr(VI) or pyrene and here a new isolate, called the Z6 strain, was demonstrated to remove both simultaneously.

Biotreatment of pyrene and Cr(VI) combined water pollution by mixed bacteria.

Pyrene and chromium (Cr(VI)) are persistent pollutants and cause serious environmental problems because they are toxic to organisms and difficult to remediate. The toxicity of pyrene and Cr(VI) to three crops (cotton, soybean and maize) was confirmed by the significant decrease in root and shoot biomass during growth in pyrene/Cr(VI) contaminated hydroponic solution. Two bacterial strains capable of simultaneous pyrene biodegradation and Cr(VI) reduction were isolated and identified as Serratia sp.

Remediation potential of immobilized bacterial consortium with biochar as carrier in pyrene-Cr(VI) co-contaminated soil.

Polycyclic aromatic hydrocarbons (PAHs) and potentially toxic trace elements (PTEs) soil contamination have become areas of concern. Bioaugmentation is regarded as an effective bioremediation method, however it is difficult to simultaneously degrade organic compounds and remove PTEs with individual microbial strains. Therefore, the objective of this study was to evaluate the feasibility of using immobilized microbial consortia, including two PAH-degrading bacterial strains (W1 and W2) and a Cr(VI)-reducing bacterium (Y2), for the remediation of pyrene-Cr(VI) co-contaminated soil.

High-Quality Draft Genome Sequence of Leucobacter sp. Strain G161, a Distinct and Effective Chromium Reducer.

Here, we report the genome sequence for Leucobacter sp. strain G161 due to its distinct and effective hexavalent chromium reduction under aerobic growth conditions, followed by facultative anaerobic incubation. The draft genome sequence of Leucobacter sp.

Simultaneous Cr(VI) reduction and Zn(II) biosorption by Stenotrophomonas sp. and constitutive expression of related genes.

Objectives: To investigate simultaneous Cr(VI) reduction and Zn(II) biosorption by a microorganism.

Results: A new isolate, Stenotrophomonas sp. TD3, simultaneously reduced Cr(VI) and achieved Zn(II) biosorption.

Bioremediation of hexavalent chromate using permeabilized Brevibacterium sp. and Stenotrophomonas sp. cells.

Bioremediation has been found to be a useful method for removing hexavalent chromium (Cr(VI)), which is very toxic, from wastewater. Two strains of bacteria that were able to reduce Cr(VI) effectively were isolated from Cr(VI) contaminated soil samples and identified as Brevibacterium sp. K1 and Stenotrophomonas sp.

Comparative evaluations on bio-treatment of hexavalent chromate by resting cells of Pseudochrobactrum sp. and Proteus sp. in wastewater.

Two marine bacterial strains, B5 and H24, were isolated from long-term Cr(VI) contaminated seawater and identified as Pseudochrobactrum and Proteus, respectively, based on 16S rRNA gene sequence analyses. Both strains were examined for their tolerance to Cr(VI) and other metal salts and their abilities to reduce Cr(VI) to trivalent chromium [Cr(III)]. Growing cells of Pseudochrobactrum sp.

Distinct and effective biotransformation of hexavalent chromium by a novel isolate under aerobic growth followed by facultative anaerobic incubation.

A bacterial isolate (G161) with high Cr(VI)-reducing capacity was isolated from Cr(VI)-contaminated soil and identified as Leucobacter sp. on the basis of 16S rRNA gene sequence analysis. The isolate was a Gram-positive, aerobic rod.

Expression and functional analysis of aminotransferase involved in indole-3-acetic acid biosynthesis in Azospirillum brasilense Yu62.

In this study, atrC (a novel gene from Azospirillum brasilense identified in our laboratory) was expressed in Escherichia coli, and SDS-PAGE analysis of the expressed AtrC revealed the apparent molecular weight of 45 kD. When analyzed under non-denaturing PAGE conditions and using L-tryptophan as a substrate, the purified AtrC protein exhibited aminotransferase activity, while crude protein extracts from A. brasilense Yu62 showed two activity bands with molecular masses estimated as 44 and 66 kD.

Characterization of two trpE genes encoding anthranilate synthase alpha-subunit in Azospirillum brasilense.

The previous report from our laboratory has recently identified a new trpE gene (termed trpE2) which exists independently in Azospirillum brasilense Yu62. In this study, amplification of trpE(G) (termed trpE1(G) here) confirmed that there are two copies of trpE gene, one trpE being fused into trpG while the other trpE existed independently. This is the first report to suggest that two copies of the trpE gene exist in this bacterium.

Development of methods for determination of the residues of 15 pesticides in medicinal herbs Isatis indigotica Fort. by capillary gas chromatography with electron capture or flame photometric detection.

Two multiresidue methods were developed for the determination of 15 pesticides (organochlorines, organphosphorus compounds, pyrethroids, and fungicides) in medicinal herbs Isatis indigotica Fort. and its formulations. The analytical procedure is based on ultrasonic assisted extraction and liquid-liquid extraction (LLE).