Cell-to-cell cross talking by laboratory E. coli strains engineered to produce antibiotics, industrial polymers or other products in fermentation vessels can lead to stress in the culture and severely limit product output. But scientists with CBR and partners have begun to decipher and override stress 'talk' among cells of recombinant E. coli. CBR is part of the University of Maryland Biotechnology Institute (UMBI).
In separate fermentation experiments with strains of E. coli that produce two important model products--interleukin-2 or organophosphorus hydrolase--the team increased product output by three to four times. The first product is an important drug in preventing cancer and HIV. The latter is a detoxifying agent for biowarfare nerve agents.
The scientists achieved higher yields of both products by either conditioning the bacterial cultures with high levels of molecules from a signaling pathway called AI-2, or by splicing the LuxS gene for quorum signaling into the recombinant E. coli.
"This is great," says team leader William Bentley, CBR research professor. "We want to understand what are the receptor molecules on these cells, to understand the communication circuitry," he adds. The experimental techniques are applicable to boosting production of many other products in E. coli cultures. However, the researchers say they are only beginning to understand and control the communications circuitry of E. coli and other bacterial cells.
E. coli is a common enteric bacterium that is one of the most highly studied microbes, with its genome and basic physiology well known. It is also one of the easiest vehicles for genetic engineering and a workhorse for metabolic engineering, an emerging branch of i
Contact: Steve Berberich
University of Maryland Biotechnology Institute