Engineering outer-membrane proteins in Pseudomonas putida for enhanced heavy-metal bioadsorption

Area of Science:

• Biotechnology and Environmental Science
• Microbial Engineering for Bioremediation

Background:

• Metallothioneins (MTs) are cysteine-rich proteins known for strong metal-binding capabilities.
• Current methods for heavy metal remediation in industrial wastewater face challenges.
• Recombinant expression of MTs in bacteria offers potential for enhanced bioremediation.

Purpose of the Study:

• To engineer Pseudomonas putida for increased heavy metal chelation.
• To express a hybrid protein of mouse metallothionein and Neisseria IgA protease beta domain in Pseudomonas outer membrane.
• To evaluate the enhanced metal-binding capacity and protein localization in the engineered bacteria.

Main Methods:

• Genetic engineering of Pseudomonas putida to express a fusion protein.
• Utilizing the autotranslocating capacity of the Neisseria IgA protease beta domain for outer membrane targeting.
• Quantifying the metal-binding capacity of the engineered bacterial cells.

Main Results:

• Successfully expressed a hybrid mouse MT-Neisseria IgA protease beta domain protein in the Pseudomonas putida outer membrane.
• Achieved a three-fold increase in the metal-binding capacity of the engineered Pseudomonas cells.
• Demonstrated successful autotranslocation and outer membrane anchoring of the hybrid protein in Pseudomonas.

Conclusions:

• Engineered Pseudomonas putida exhibits significantly enhanced heavy metal chelation ability.
• This study validates the use of Neisseria IgA protease beta domain for outer membrane protein display in Pseudomonas.
• The developed system shows promise for novel bioremediation strategies for industrial heavy metal pollution.