We are interested in the environmental applications of microbiology and biotechnology such as re-engineering the global nitrogen cycle, sustainable sanitation, public health microbiology, water and wastewater treatment, bioenergetics (including biofuels) and biorefining. Professor Chandran’s research on the global nitrogen cycle and engineered wastewater treatment has been widely recognized. In 2011 he received a $1.5 million grant from the Bill & Melinda Gates Foundation grant to develop a transformative new model in water and sanitation in Africa. His work is focused on integrating microbial ecology, molecular biology, and engineering to transform wastewater, sewage, and other “waste” streams from problematic pollutants to valuable resources. Traditional facilities for biologically treating wastewater remove pathogens, organic carbon, and nutrients, where necessary, through decades-old technology that requires vast amounts of energy and resources, releases harmful gases into the atmosphere, and leaves behind material that must be discarded. Chandran has a different approach to wastewater treatment: he investigates producing useful resources such as fertilizers, chemicals, and energy sources, in addition to clean water, in a way that takes into account the climate, energy, and nutrient challenges we face today.
RE-ENGINEERING THE NITROGEN CYCLE
We focus on the influence of nitrogen on global climate and the biosphere. As N2, nitrogen is a largely non-reactive, but crucial, part of Earth’s atmosphere. As nitrous oxide (N2O), it is one of the strongest greenhouse gases. As nitric oxide (NO), it plays a role in ozone depletion and, at the molecular scale, in promoting resistance to anti-microbial products. Both can be formed in the process of wastewater treatment. Ideally, household and industrial wastewater is treated to convert nitrogen-containing compounds to N2. However, the U.S. Environmental Protection Agency estimates that improper treatment methods lead to the accidental release of 24,000 tons of nitrous oxide in the U.S. alone each year. Because the gas is more than 300 times more effective at trapping heat in the atmosphere, the combined effect is equivalent to having more than one million extra cars on the road. We’d ideally like to convert everything to di-nitrogen gas, but if we don’t engineer bioreactors well, we’ll just end up impairing air quality and possibly creating robust microorganisms
MODELING MICROBIAL COMMUNITIES
Notwithstanding the recent strides made in chemical and biological characterization techniques, numerous steps in environmentally relevant microbial processes such as activated sludge wastewater treatment are still modeled using black-box descriptors.
Our group goes beyond simply developing structured mathematical models that describe microbial communities and interactions. We develop optimal experimental designs using which these models can be parameterized and applied meaningfully.
Despite ongoing genome sequencing and discovery of many microorganisms in unexpected environmental niches, it is clear that we know little about the complement of microbial metabolic pathways and their interaction with environmental factors.
We employ techniques like qPCR and custom DNA chips along with advanced bioinformatics to resolve community structure with metabolism
The current model of human fecal waste and wastewater treatment is primarily focused on a systematic removal of the primary contaminants of interest, carbon, nitrogen, and phosphorus. It is the sheer energy required that renders the current mode of wastewater treatment prohibitively expensive almost all over the world. On the other hand, if the focus can be on recovery rather than on removal, then wastewater treatment and the provision of sanitation could be made resource and energy neutral and positive. Sewage offers enormous potential for recovery of resources such as smart soils, chemicals, synthetic nutrients, fertilizers, bioplastics, and alcohols as pictured above, clockwise. Resource recovery as opposed to resource removal serves as a far superior model to follow for future sustainable cities.
MICROBIAL ECOLOGY OF COMMUNITIES
Interrogating the core biocatalysts in microbial communities may provide powerful information on community structure and function. To this end, we apply state of the art tools to answer questions directed at these communities such as:
· Who is where ? (identity, abundance and spatial location)
· What are they doing ? (function)