Microbial production of bulk chemicals: development of anaerobic processes.

Innovative fermentation processes are necessary for the cost-effective production of bulk chemicals from renewable resources. Current microbial processes are either anaerobic processes, with high yield and productivity, or less-efficient aerobic processes. Oxygen utilization plays an important role in energy generation and redox metabolism that is necessary for product formation. The aerobic productivity, however, is relatively low because of rate-limiting volumetric oxygen transfer; whereas the product yield in the presence of oxygen is generally low because part of the substrate is completely oxidized to CO₂. Hence, new microbial conversion processes for the production of bulk chemicals should be anaerobic. In this opinion article, we describe different scenarios for the development of highly efficient microbial conversion processes for the anaerobic production of bulk chemicals.