The secret, the EU-funded BIOCORIN project found, was to harness the power of microscopic organisms. By identifying bacteria capable of neutralising compounds that attack metal, the team has developed a solution capable of increasing coating infrastructure durability by up to 30 % and decreasing costs by 20 %, compared to current solutions.

“The project consortium contains experts in product exploitation, and we are currently working on a model to commercialise this promising technology,” says project coordinator Edith Guedella Bustamante from Acciona in Spain.

A corrosive problem

Microbial induced corrosion – known as MIC – is caused by microorganisms that can attack both metallic and non-metallic materials. For major infrastructure such as motorway bridges, gas and liquid transmission pipelines, ships and railroads, this presents a serious threat that can lead to significant repair costs.

“The corrosion of metallic structures has a huge economic impact on modern society,” says Guedella. “There are direct costs related to the design, manufacture, and construction of corrosion protection, while there are also ongoing indirect costs related to corrosion-related inspection, maintenance and repairs.”

Indeed, the financial impact of metal corrosion in Europe exceeds €1.32 trillion a year, with up to 50 % of cases associated with microorganisms. While a variety of highly toxic materials have been shown to be effective in controlling MIC, these cannot be readily degraded, causing a great deal of environmental damage. Paints containing biocides also present both environmental and health risks.

“Although there is data available on the fate and behaviour of biocides most commonly used in Europe, very little is known about many other biocides,” adds Guedella. “In the last 10 years, there has been an improvement in understanding of the occurrence, fate and effects of antifouling biocides, and the use of certain biocides has been restricted in some countries.”

The power of microorganisms

The BIOCORIN project therefore attempted a new approach by giving corrosive bacteria a taste of its own medicine. By applying anti-fouling microorganisms to tackle the microorganisms responsible for MIC, the project has developed a greener, more environmentally friendly way of maintaining infrastructure and fighting corrosion.

“In addition, by substituting chemical compounds and dangerous substances with microorganisms, greenhouse gases will not be released into the environment,” says Guedella. “And because infrastructure maintenance is often a dangerous activity, any improvement towards the health and safety of workers is clearly a step in the right direction.” In life-cycle assessments, the BIOCORIN solution has demonstrated a significant reduction in emissions – 46 % for CO2 and 71 % for methane emissions – compared with other, traditional antifouling solutions.

The BIOCORIN team used genetic techniques to identify useful bacteria, fungi and yeast, from samples obtained from four different climatic zones. Researchers then identified two candidate bacteria with anti-MIC properties and incorporated these microorganisms in a sol-gel matrix that was applied to metal.

“Preliminary tests of chemical corrosion resistance, mechanical stability and anti-fouling microorganism viability have yielded promising results,” says Guedella. “Specifically, the coating retained corrosion resistance after immersion in a saline solution for 40 days, and all microorganisms were still viable after the 11-day test point.”

The BIOCORIN project is due for completion in August 2015, and has received EU funding totalling nearly €3 million.

Below SEM images of anti-fouling microorganisms

© ACCIONA Infraestructuras S.A.