Biological bactericides effective against tuberculosis


Danielle Pretorius, working on Bacillus

Tuberculosis (TB) is second only to HIV/AIDS as the greatest global cause of deaths due to a single infectious agent. In 2013, 9 million people developed TB, and 1.3-1.5 million people died from this cause.  Over 95% of cases and deaths were in developing countries with Africa carrying the greatest burden of 280 cases per 100 000 population.

Children and people living with HIV/AIDS are particularly vulnerable. In 2013, more than 500 000 children (0-14 years) contracted TB, 80 000 with a fatal outcome. In the same year, about 360 000 people died from HIV-associated TB. Again, Africa carried a large burden with 78% of all new cases of TB in HIV-positive people. A growing concern is multi-drug resistant TB (MDR-TB) which has reached crisis proportions with only 48% of MDR-TB cured globally.  This research project will focus on the bacterial production of novel antimicrobial agents effective against causative agents of TB, including MDR-TB organisms.

Lipopeptide molecules, produced by many Bacillus species, have been shown to exhibit biocidal activity against bacterial pathogens. Specifically, the homologues of the surfactin group of lipopeptides, which inhibit growth of TB surrogates, are potential weapons in the war against TB.   In this project, the process conditions and operational strategy of the production process, both the upstream production of the surfactin by the Bacillus and the downstream processing involving concentration and purification of the surfactin, will be optimised to produce the maximum concentration with homologue ratios providing maximal efficacy against TB organisms.

The proposed research approach will be multidisciplinary in nature with interrelated components of surfactin production, purification and efficacy, mediated by chemical engineers, microbiologists, biochemists and biotechnologists.  It is envisaged that by connecting specialists in the fields of engineering and life sciences, that a synergistic solution to this complex problem will be realised.

For more information, please contact project leader Prof Kim Clarke, at


Dr Vivek Rangarajan, working on Bacillus

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