K. T. Shanmugam
Description of Research
General area: bacterial anaerobic metabolism; dinitrogen fixation and dihydrogen production by fermentative bacteria and cyanobacteria; molybdate transport and regulation.
Dr. Shanmugam’s research at the University of Florida, Florida Center for Renewable Chemicals and Fuels (FCRC) is focused towards metabolic engineering of bacterial biocatalysts for production of chemicals and liquid fuels at high yield and purity. His interest in metabolic engineering dates back to early 1970s with the demonstration of engineered bacterial biocatalysts that convert atmospheric dinitrogen to ammonia and export to the environment. This led to the development of cyanobacteria that produce ammonia from dinitrogen, water and sunlight for growth of rice plants in N-deficient growth medium. Further metabolic engineering of these cyanobacteria led to bacterial biocatalysts that ferment hexoses photoheterotrophically to dihydrogen at a dihydrogen to hexose yield of 12-14.
More recently, the collaborative research with Dr. L. O. Ingram, director of FCRC, is focused on developing bacterial biocatalysts that produce ethanol, lactic acid, acetic acid, pyruvic acid, succinic acid, alanine, etc. Recombinant ethanologenic Escherichia coli strains have the ability to ferment all the sugars in lignocellulosic biomass to ethanol. We are also engineering bacterial biocatalysts such as Bacillus coagulans and other thermotolerant/thermophilic bacteria that ferment both hexose and pentose sugars to optically pure lactic acid at a temperature and pH that are also optimal for fungal cellulases towards reducing the overall cost of cellulases, a significant cost component in biorefinery. Biochemical and physiological studies of B. coagulans show that this bacterium differs from lactic acid bacteria used by the industry in its ability to convert all the pentose carbon to lactic acid. We also developed an alternate pathway for fermentation of sugars to ethanol that relies only on native genes and enzymes for expanding the number of ethanologenic biocatalysts with innate properties that are important for industrial use. These metabolic engineering efforts are aimed at understanding the inherent physiology of the bacterial cell that provide a knowledge base towards developing bacterial biocatalysts as the fuel and commodity chemicals industry is attempting to reduce its petroleum dependence.
- Teaching Interests
- MCB 5305L - Microbial Genetics and Biotechnology Laboratory
- MCB 6465 - Microbial Metabolic Engineering