Biodiesel is a clean and renewable biofuel that is compatible with existing energy infrastructure and diesel engines. However, before the large-scale, cost-effective production of biodiesel can be fully realized, two key challenges must be overcome. The first challenge is the inexpensive and sustainable production of the biodiesel feedstock, and the second challenge is an effective process for extraction for and recovery of the intracellular lipids, the precursors to biodiesel, from the feedstock. Oleaginous bacteria are a potentially attractive feedstock for biodiesel production, as they accumulate high levels triacylglycerol (TAG) lipids (20-75% of dry cell weight), grow rapidly, reach high cell densities in culture, and utilize diverse carbon sources. The overall goal of the proposed research is to develop and study bacterial strains that produce intracellular lipids from biomass-derived hydrolysate crude mixtures and then release the lipids through controlled lysis of the bacteria with bacteriophage.
Bacteriophage (phage), are well known for their ability to proliferate on and lyse bacterial cultures. The proposed research will characterize phages specific for the TAG-accumulating bacteria, explore the use of these phages or their bacteriolytic genes to effect release of the accumulated TAG, and characterize the fundamental mechanisms underlying these processes. The proposed research has three objectives. The first objective is to determine if TAG-accumulating bacteria can grow in the presence of common inhibitory compounds, such as furaldehydes and lignin-derived phenolic compounds, found in lignocellulosic hydrolysates, in addition to the biomass carbohydrates. The second objective is to determine if phages or bacterial strains expressing phage lysis genes can effectively lyse TAG-accumulating bacteria and release TAGs from the host cells. The third objective is to extract TAGs from the model TAG-accumulating bacteria by application of a phage cocktail or expression of cloned phage lysis genes.
The proposed education and outreach activities focus on student and high school teacher training, mentoring of students from under-represented minorities, and development of internet-based public outreach and teaching tools. Two Ph.D. students will receive interdisciplinary training at the interface of environmental engineering, microbiology, and virology. It is also expected that two undergraduate students will be given research experiences in the PIs laboratory that are coordinated with the Center for Phage Technology at Texas A & M University (TAMU). The undergraduate student research participants will be recruited and mentored through the TAMU Louis Stokes Alliance for Minority Participation program. The PI will also work closely with two high school teachers during summers through the TAMU Research Experience for Teachers (RET) program. Outcomes of this study will communicated through the PIs web site, by podcasting through the College of Engineering's "Engineering Works" service, and by YouTube videos.