As one of the oldest forms of painting art created by humankind,
ancient murals are widely found across various regions of the world.
However
due to environmental changes and the impact of human
activities,
these cultural treasures,
with histories spanning hundreds or even thousands of years,
are now facing unprecedented challenges.
Climate warming and humidification have enabled microorganisms to grow on mural relics in originally relatively arid regions, causing severe deterioration of these irreplaceable cultural artifacts.
The physical and chemical reactions triggered by the growth of microorganisms, especially filamentous fungi in the base layer, accelerate the separation of the substrate.
Bacteria and fungi consume organic binders such as animal glue in mural materials, reducing the cohesion of the pigment layer and causing it to peel off and be lost.
Organic acids produced by fungal metabolism dissolve and chelate metal cations in mineral pigments, leading to the formation of various secondary minerals and resulting in cracking, powdering, and peeling of the mural surface.
The vigorous metabolic reactions of microorganisms affect mineral pigments in the environment, causing color changes, such as the transformation of lead white into black lead dioxide.
During their growth, microorganisms produce various pigment compounds, such as melanin and carotenoids, leading to discoloration of the murals and alteration of the cultural relic materials.
How can we protect ancient murals
from microbial destruction without causing
further damage ?
Our Solution
A chassis bacterium is engineered to express and release antimicrobial peptides, killing and inhibiting environmental microbes.
It is designed to produce laccase and peroxidase to break down melanin and carotenoids; its modified scaffold uses specific binding peptides to prevent damage to the mural.
The strain features a dual-control switch that releases antimicrobial peptides in acidic conditions and produces cleaning agents in neutral-alkaline environments.
Also incorporates an arabinose-inducible suicide module to prevent engineered microbes from escaping into the environment.
