Peeples Lab

Microbial biofilms are significant in a variety of settings including the human microbiome, infectious disease, industrial processes, and environmental remediation. Because of the ubiquity of biofilms, there is a great interest in understanding the interaction of the biofilm matrix with chemicals in the biofilm surroundings. In this research, we are examining key functions within the layers of microbial biofilms including gene expression, nanoparticle formation and dissolution, and pollutant entrapment and degradation. We use static and continuous flow biofilm reactors to evaluate the impact of flow rates in optimization of the system. Current efforts are to characterize the dynamics of biofilm formation and particle formation in relation to the chemical environment of the films.

We have developed ‘greener’ approaches to synthesize chiral drug precursor molecules. Such chemoenzymatic and whole-cell synthesis processes compete favorably over traditional chemical approaches that employ multiple steps with numerous hazardous chemicals. The greener process involves bridging medicinal chemistry, microbiology, and biochemical engineering. We have employed biphasic process to increase productivity of the biocatalytic systems. Whole cell conversion systems include applications with bacterial and fungal transformations as well as enzymatic processes. This “bio-resolution” process for separating these chiral molecules is more environmentally favorable because the reagents are less hazardous and biodegradable.

An understanding of microbial physiology may enable the design of novel biocatalysts for directed biotransformations. The Peeples group has pursued metabolic engineering through cloning and expressing foreign genes in bacterial cultures. These biocatalysts are useful for the remediation of environmental pollutants and the sustainable production of valuable chemicals.

Green chemistry approaches to utilize enzymes or cellular systems must be more robust to be economically viable alternatives to traditional catalysis. Gaining and understanding of adaptation and stability of natural systems that thrive under extreme conditions guides our development of biotcatalysts for specialty chemicals and pharmaceutical synthesis. We are studying the synergy of the biocatalysis and agricultural applications on the regulation of oxidative capacity within Beauveria bassiana. Acting in nature as an insect pathogen, this filamentous fungus has found worldwide use as a biopesticide. The organism is also a biocatalyst for oxidative conversions. We have developed a strain library adapted to n-alkanes. These strains show enhanced abilities to carry out sulfoxidation reactions and steroid transformations through induced oxidoreductases.

Knowledge of unique physiological function may enable the engineering of stability in industrial and environmental biocatalysts. Current research involves the discovery of unique enzymes for biotransformation, as well as the evaluation of molecular interactions that govern protein stability under extreme conditions. These have utility in the conversion of biomass to fuels and chemicals. The Peeples group is evaluating the evolution of stabilizing adaptations in microbial systems and their interaction with the environment.

Biomass is an untapped resource which can be used directly as fuel. It is also beneficial and profitable to produce commodity chemicals and fuels from refining waste biomass. The Peeples group is studying the conversion of biomass-derived feedstocks to organic acids and solvents. The potentials to produce biogas as well as the chemical fuels and intermediates is being actively explored. The research is focused on developing appropriate microbial cultures for mixed waste anaerobic digestion. Feedstocks from local agriculture processing industries are being utilized in this effort.