Related Experiment Video
Updated: Jul 13, 2026
15:28
Engineering Adherent Bacteria by Creating a Single Synthetic Curli Operon
Published on: November 16, 2012
Bacteria metabolically engineered for enhanced phytochelatin production and cadmium accumulation
Seung Hyun Kang1, Shailendra Singh, Jae-Young Kim
1Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA.
Applied and Environmental Microbiology
|August 7, 2007
Summary
Engineered microbes efficiently remove cadmium using phytochelatins (PCs). Overexpressing PC synthase and related genes in E. coli significantly boosted cadmium accumulation for bioremediation applications.
Area of Science:
- Biotechnology
- Environmental Science
- Microbiology
Background:
- Phytochelatins (PCs) are peptides with high affinity for heavy metals.
- Developing efficient microbial sorbents for cadmium removal is crucial for environmental remediation.
Purpose of the Study:
- To engineer Escherichia coli for enhanced cadmium accumulation using phytochelatins.
- To optimize PC synthesis and cadmium uptake pathways in recombinant E. coli.
Main Methods:
- Overexpression of PC synthase (SpPCS) from Schizosaccharomyces pombe in E. coli.
- Coexpression of a feedback-desensitized gamma-glutamylcysteine synthetase (GshI) to increase precursor supply.
- Introduction of a cadmium transporter (MntA) to enhance cellular uptake.
Main Results:
- Engineered E. coli synthesized PCs and exhibited 7.5-fold higher Cd accumulation.
- Coexpression of GshI further increased PC production (10-fold) and Cd accumulation (2-fold).
- Inclusion of MntA resulted in an additional 1.5-fold increase in Cd accumulation, reaching 31.6 micromol/g dry weight.
Conclusions:
- Genetic engineering of E. coli with SpPCS, GshI, and MntA significantly enhances cadmium accumulation capacity.
- This approach offers a promising strategy for developing microbial biosorbents for heavy metal remediation.
- The engineered strain demonstrated over 25-fold higher Cd accumulation compared to the control.
Related Concept Videos
02:50Transgenic Plants
Recombinant DNA technology called transgenesis is often used to add a foreign gene or remove a detrimental gene from an organism. Such genetically modified organisms are called transgenic organisms.
The first-ever transgenic plant was a tobacco plant developed in 1983 that showed resistance against the tobacco mosaic virus. Since then, many transgenic plants have been developed and commercialized for improving the agricultural, ornamental, and horticultural value of a crop plant. Transgenic...
The first-ever transgenic plant was a tobacco plant developed in 1983 that showed resistance against the tobacco mosaic virus. Since then, many transgenic plants have been developed and commercialized for improving the agricultural, ornamental, and horticultural value of a crop plant. Transgenic...
01:27Production of Antibiotics
Penicillin, one of the earliest and most widely used antibiotics, is produced industrially by the filamentous fungus Penicillium chrysogenum. Large stirred-tank bioreactors ranging from tens to hundreds of thousands of liters maintain tightly controlled temperature, pH, and dissolved oxygen conditions to support fungal metabolism and maximize antibiotic yield. Penicillin is a secondary metabolite, synthesized primarily during the stationary growth phase, which requires a carefully managed...
00:53Transgenic Organisms
Overview
01:24iChip
The cultivation of environmental microorganisms has long been hindered by the inability to replicate complex native conditions in vitro. The isolation chip (iChip) addresses this limitation by facilitating the growth of previously uncultivable microorganisms through in situ incubation. Designed for high-throughput microbial cultivation, the iChip comprises hundreds of microchambers, each capable of housing a single microbial cell. These microchambers are loaded with a mixture of molten agar and...
01:24Evolution of New Traits in Microbes
Microorganisms evolve rapidly due to their large population sizes and short generation times, often exhibiting measurable changes within days under laboratory conditions. Natural selection acts on standing genetic variation, enabling the retention and amplification of beneficial traits that confer fitness advantages in changing environments.Adaptive Pigment Regulation in RhodobacterIn Rhodobacter, a genus of purple non-sulfur bacteria, light-harvesting pigments such as bacteriochlorophyll and...
01:22Bioreactor Controls-III
Strain improvement is a foundational strategy in industrial microbiology aimed at maximizing microbial productivity, particularly because natural isolates typically yield commercially valuable products in very low concentrations. Although optimizing the culture medium and environmental conditions can improve yields, these adjustments are inherently limited by the organism’s genetic potential. As a result, the focus shifts toward genetic modifications to enhance biosynthetic capacity. The...