title: Biocatalysis on the surface of Escherichia coli: melanin pigmentation of the cell exterior.
abstract: Today, it is considered state-of-the-art to engineer living organisms for various biotechnology applications. Even though this has led to numerous scientific breakthroughs, the enclosed interior of bacterial cells still restricts interactions with enzymes, pathways and products due to the mass-transfer barrier formed by the cell envelope. To promote accessibility, we propose engineering of biocatalytic reactions and subsequent product deposition directly on the bacterial surface. As a proof-of-concept, we used the AIDA autotransporter vehicle for Escherichia coli surface expression of tyrosinase and fully oxidized externally added tyrosine to the biopolymer melanin. This resulted in a color change and creation of a black cell exterior. The capture of ninety percent of a pharmaceutical wastewater pollutant followed by regeneration of the cell bound melanin matrix through a simple pH change, shows the superior function and facilitated processing provided by the surface methodology. The broad adsorption spectrum of melanin could also allow removal of other micropollutants.
authors: Division of Industrial Biotechnology, School of Biotechnology, KTH Royal Institute of Technology, Albanova University Center, SE 10691 Stockholm, Sweden.
authors: Martin
authors: M
authors: Gustavsson
authors: Division of Industrial Biotechnology, School of Biotechnology, KTH Royal Institute of Technology, Albanova University Center, SE 10691 Stockholm, Sweden.
authors: David
authors: D
authors: Hörnström
authors: Division of Industrial Biotechnology, School of Biotechnology, KTH Royal Institute of Technology, Albanova University Center, SE 10691 Stockholm, Sweden.
authors: Susanna
authors: S
authors: Lundh
authors: Division of Industrial Biotechnology, School of Biotechnology, KTH Royal Institute of Technology, Albanova University Center, SE 10691 Stockholm, Sweden.
authors: Jaroslav
authors: J
authors: Belotserkovsky
authors: Division of Industrial Biotechnology, School of Biotechnology, KTH Royal Institute of Technology, Albanova University Center, SE 10691 Stockholm, Sweden.
authors: Gen
authors: G
authors: Larsson
mesh_terms: D018830:Adhesins, Escherichia coli / Q000235:genetics / Q000378:metabolism; D055162:Biocatalysis; D002473:Cell Wall / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D008543:Melanins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014442:Monophenol Monooxygenase / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D014443:Tyrosine / Q000378:metabolism
chemical_list: C075559:AIDA-I protein, E coli; D018830:Adhesins, Escherichia coli; D008543:Melanins; D014443:Tyrosine; D014442:Monophenol Monooxygenase