Graduate Student Exit Seminar: Brendan Higgins, Thursday, November 13, 11am-12:30pm, 2045 Bainer Hall


Thursday, November 13, 2014 
11:00 AM - 12:30 PM, 2045 Bainer Hall

Topic: Co-culturing green algae with bacteria for enhanced growth and biofuel production 

Presenter: Brendan Higgins 
PhD Degree Candidate 
Department of Biological & Agricultural Engineering 
University of California, Davis 


Algae offer the potential to simultaneously produce biofuels and treat wastewater but significant barriers to commercialization remain. Wastewater often contains organic material in addition to a diverse microbial community. Under high organic loadings, heterotrophs may out-compete algae for resources. To gain insight into algal-microbial interactions we studied a co-culture system which utilized the model green algae Chlorella minutissima and the model bacterium Escherichia coli. We attempted to isolate the effects of the bacteria on culture growth rates, lipid production, starch production, organic substrate uptake, and substrate utilization efficiency. The results suggested a symbiotic relationship between the two organisms under mixotrophic conditions, particularly at high substrate levels. Notably, C. minutissima growth and substrate uptake increased by up to 600% in the presence of E. coli whereas C. minutissima only had modest effects on E. coli growth. We also observed very high levels of neutral lipids, specifically triacylglyerol, in high-substrate co-cultures. Moreover, the fatty acid profiles in those same co-cultures had lower levels of saturation than their axenic counterparts which should lead to higher quality biodiesel with better oxidative stability. These results suggest that co-culturing can enhance both the quantity and quality of biofuel from algae but additional research is required to determine the extent of this phenomenon among species. 


Brendan Higgins is a PhD candidate in Biological Systems Engineering and studies algal biofuel production, wastewater treatment, and organism interaction in Jean VanderGhyensts lab. He also collaborates with researchers at the UC Davis metabolomics core to study metabolism in algae. 

Coffee and cookies will be served.