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Abstract Advanced treated municipal wastewater is an important alternative water source for agricultural irrigation. However, the possible persistence of chemical and microbiological contaminants in these waters raise potential safety concerns with regard to reusing treated wastewater for food crop irrigation. Two low-cost and environmentally-friendly filter media, biochar (BC) and zero-valent iron (ZVI), have attracted great interest in terms of treating reused water. Here, we evaluated the efficacy of BC-, nanosilver-amended biochar- (Ag-BC) and ZVI-sand filters, in reducing contaminants of emerging concern (CECs),Escherichia coli (E. coli)and total bacterial diversity from wastewater effluent. Six experiments were conducted with control quartz sand and sand columns containing BC, Ag-BC, ZVI, BC with ZVI, or Ag-BC with ZVI. After filtration, Ag-BC, ZVI, BC with ZVI and Ag-BC with ZVI demonstrated more than 90% (> 1 log) removal ofE. colifrom wastewater samples, while BC, Ag-BC, BC with ZVI and Ag-BC with ZVI also demonstrated efficient removal of tested CECs. Lower bacterial diversity was also observed after filtration; however, differences were marginally significant. In addition, significantly (p < 0.05) higher bacterial diversity was observed in wastewater samples collected during warmer versus colder months. Leaching of silver ions occurred from Ag-BC columns; however, this was prevented through the addition of ZVI. In conclusion, our data suggest that the BC with ZVI and Ag-BC with ZVI sand filters, which demonstrated more than 99% removal of both CECs andE. coliwithout silver ion release, may be effective, low-cost options for decentralized treatment of reused wastewater. Graphical Abstract
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Hybrid Living Capsules Autonomously Produced by Engineered Bacteria
Abstract Bacterial cellulose (BC) has excellent material properties and can be produced sustainably through simple bacterial culture, but BC‐producing bacteria lack the extensive genetic toolkits of model organisms such asEscherichia coli(E. coli). Here, a simple approach is reported for producing highly programmable BC materials through incorporation of engineeredE. coli. The acetic acid bacteriumGluconacetobacter hanseniiis cocultured with engineeredE. coliin droplets of glucose‐rich media to produce robust cellulose capsules, which are then colonized by theE. coliupon transfer to selective lysogeny broth media. It is shown that the encapsulatedE. colican produce engineered protein nanofibers within the cellulose matrix, yielding hybrid capsules capable of sequestering specific biomolecules from the environment and enzymatic catalysis. Furthermore, capsules are produced which can alter their own bulk physical properties through enzyme‐induced biomineralization. This novel system uses a simple fabrication process, based on the autonomous activity of two bacteria, to significantly expand the functionality of BC‐based living materials.
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- Award ID(s):
- 2004875
- PAR ID:
- 10446361
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Science
- Volume:
- 8
- Issue:
- 11
- ISSN:
- 2198-3844
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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