Methods and Systems for Continuous Production of Dehalococcoides

Organic contaminants, such as chlorinated ethenes, are pervasive worldwide, and in situ bioaugmentation is one of the most widely employed methods for remediation. Specialized bacteria of the genus Dehalococcoides are routinely used for in situ bioremediation of chlorinated ethenes and other organic contaminants. For effective remediation it is recommended to have 10⁷ Dehalococcoides cells per liter of groundwater. However, these microbes are slow-growing and difficult to culture in high density. There is only one report where a density of 10¹² cells/L of Dehalococcoides was achieved, and it took 35 days to reach that density.

Researchers at the Biodesign Institute of Arizona State University have developed a method and system for continuous production of Dehalococcoides in continuous flow stirred-tank reactors (CSTRs). Through optimization of growth conditions, growth medium, and reactor construction materials, a density of 10¹² cells/L of Dehalococcoides was achieved in just three days, which is a tenfold improvement over the best reported culture process.

This method provides the fastest production rate of high-cell density Dehalococcoides cultures and has the potential to revolutionize production of bioaugmentation cultures for treatment of chlorinated ethenes.

Potential Applications

• High density production of Dehalococcoides in continuous flow stirred-tank reactors

Benefits and Advantages

• Rapid, higher density production - only three days to reach a cell density of 10¹² cells/L
• Cultures can be stored for longer durations - helps streamline production
• The novel growth medium minimizes proliferation of competing microorganisms and enhances growth of beneficial microbes
• These Dehalococcoides cultures convert trichloroethene (TCE) to mostly ethene at a 3-d HRT
• The reactor construction materials minimize possible inhibition of anaerobic microorganisms in the CSTR

For more information about the inventor(s) and their research, please see
Dr. Krajmalnik-Brown's directory webpage