In line with the general focus of the Institute of Microbiology and Biotechnology, we are also investigating strategies to develop the findings of our basic research into health-related products. Bacteriocins are antimicrobial peptides (AMPs) produced by bacteria to inhibit competitors in their natural environments. Several bacteriocins are widely used as food preservatives. Due to the rapid increase in antibiotic resistant bacteria, bacteriocins are also discussed as alternatives to antibiotics to treat infections for therapeutic purposes. Currently, industrial production of bacteriocins is performed exclusively with natural producer organisms on complex substrates and products are commercialized as semi-purified preparations or crude fermentates. To allow clinical application and entry of novel bacteriocins into the market, efficacy of production and purity of the product need to be improved. One possibility is to shift production to recombinant biotechnological production host. Due to the intrinsic antimicrobial activity of bacteriocins, this is not a trivial task. Recently, were able to establish recombinant production of bacteriocins using the widely used industrial workhorse organisms Corynebacterium glutamicum as host (Goldbeck et al., 2021a). Pediocin PA-1 is a linear class IIa bacteriocin without extensive modifications produced naturally by Pediococcus spp. and Lactobacillus spp. strains. An even more interesting bacteriocin from a scientific and commercial perspective is nisin, which is the most intensively studied bacteriocin. Nisin is widely used as a food preservative and is the bacteriocin with the largest market volume worldwide. It has broad antimicrobial activity against several human pathogens. However, nisin is more difficult to produce using recombinant hosts due to its high degree of posttranslational modification and, unfortunately, it is also active against C. glutamicum. In order to address these obstacles we study resistance mechanisms of bacteria against nisin and other lantibiotics (Goldbeck et al., 2021b) aiming to transfer these resistance mechanisms to C. glutamicum (Weixler et al., 2021). Additionally, we are looking for alternative approaches such as production of inactive precursors and downstream activation.

 

 

Figure: Implementation of recombinant production of bacteriocin using Corynebacterium  glutamicum. Once identified, (novel) bacteriocin gene clusters are analyzed, optimized and obtained as synthetic operons that are cloned into appropriate expression vectors. These vectors are transformed into the versatile platform organism C. glutamicum to generating tailored cell factories. Development of (large-scale) production process and downstream purification yield active recombinant bacteriocins.