Microbial Growth in Diesel Fuel

Bacteria in Diesel

When it comes to fueling your vehicle with diesel, the biggest threat comes in the smallest package. Microbes, better known as bacteria, find sustenance in diesel fuel and the water it attracts. These bacterium can lead to fuel fouling, tank corrosion, and clogged filters. In fact, a microbial colony can consume as much as 2% of your fuel while spoiling the rest. Understanding bacteria in diesel is key to protecting your diesel from a microbial growth outbreak.


Microbes reproduce at the bottom of tanks where diesel and water are stagnant and can rapidly grow with high temperatures. Typically, it is biodiesel that face the largest chance of a microbial outbreak due to the blend of both plants and animals, which is the best diet for microbes. The recent influx of these biodiesel blends has accelerated the chance for bacteria, most noticeably in the trucking, construction, and farming industries.


Once the outbreak of bacteria reaches a certain point, the fuel becomes permanently contaminated. Microbes can breed in either the storage tank or in a piece of machinery that has been holding stagnant fuel in it for an extended period of time. Whether microbes are dead or alive, they will cause fuel system damage such as corrosion, rust, and filter plugging. It is recommended to prevent bacterial growth before it starts, and even more important to eliminate it immediately once an outbreak is detected.


It is important to note the difference between microbial growth and algae. Microbial colonies are bacteria or fungus whereas algae is a photosynthetic organism which needs sunlight to thrive. Due to the lack of light present in an enclosed fuel tank, it is unlikely for algae to bloom. The bacteria found in diesel does not need light in order to survive, therefore fuel tanks become the perfect breeding ground.


We recommend that fuel be treated to control the possibility of microbial growth in diesel. It is important to use a diesel biocide or an additive that has some sort of microbial growth remover to get rid of the sludge. Fortunately, Fuel Ox prevents the threat of microbes from growing and kills the bacteria that may already have developed. It is designed for both diesel and biodiesel blends and is best added right before or right after refilling fresh fuel to the tank. Bottom line: to protect yourself from a bad batch of diesel or providing the perfect conditions for bacterial growth, be sure to use an additive with a biocide to keep on trucking!

Guy, Tech. “Microbial Growth in Fuel: What is it and How to Prevent it.” Fuel & Friction, Boost Performance Products, 2013, fuelandfriction.com/trucking-pro/microbial-growth-in-fuel-prevent/.

“Microbial Bacteria in Diesel Fuel.” My Clean Diesel, Donaldson Filtration Solutions, 7 Oct. 2010, www.mycleandiesel.com/pages/ProblemMicrobialGrowth.aspx.

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